- Email: [email protected]
Microvascular events in bone marrow related to development of and recovery from bone atrophy in thiotepa-treated rats
Exp Toxic Patho11993; 45: 129-133 Gustav Fischer Verlag Jena
Department of Pathology, Osaka Medical College, Takatsuki, Osaka, Japan
Microvascular events in bone marrow related to development of and recovery from bone atrophy in thiotepa-treated rats Y. SHIBAYAMA, M. NISHIMOTO and K. NAKATA With 7 figures Received: May 27, 1992; Revised: August 11, 1992; Accepted: August 28, 1992
Address for correspondence: Dr. Y. SHIBAYAMA, Department of Pathology, Osaka Medical College, Daigaku-Cho, Takatsuki City, Osaka, Japan.
Key words: Bone atrophy; Recovery from bone atrophy; Microcirculation of bone marrow; Thiotepa; Bone morphometry.
Summary To clarify the relationship of microvascular events in the bone marrow to the development of and the recovery from bone atrophy, we examined quantitatively and qualitatively trabecular bone, sinusoids and haematopoietic tissue in the metaphysis of the tibia of rats given thiotepa, an antitumour drug derived from nitrogen mustards. The administration of thiotepa rapidly reduced the number of haematopoietic cells causing significant dilatation of the sinusoids and atrophy of the trabecular bone 1 day after the injection. However, these changes were transient; regeneration of haematopoietic cells and normalization of the dilated sinusoids started 3 days after the injection, and the atrophied trabecular bone gradually returned to normal starting 6 days after the injection. These results imply that an extreme decrease in velocity and margination of sinusoidal blood flow following marked dilatation due to a decrease in haematopoietic cells cause atrophy ofthe trabecular bone, and that normalization of the sinusoidal blood flow following regeneration of haematopoietic cells leads to recovery from atrophy of trabecular bone.
Introduction In an earlier study we offered a hypothesis that deterioration of the microenvironment in the bone marrow, that is, the disturbance of exchange of nutrients and waste products due to circulatory changes in the sinusoids, is a cause of atrophy of trabecular bone (SHIBAYAMA et al. in press). Some investigators have reported prominent blood vessel proliferation and dilated sinusoids in the bone marrow as well as an increase in blood flow and in the velocity of blood flow in the venules of the bone marrow in immobilized animals with bone atrophy (FERNANDEZ DE V ALDERRAMA and LITTLE 1965; GEISER and TRUETA 1958; MCCLUGAGE and MCCUSKEY 1973; SEMB 1966a; SEMB 1966b; VERHAS et al. 1980). Indeed, in autopsy cases we sometimes see dilatation of the sinusoids and bone atrophy. However, it has not been clear 9
that circulatory changes lead to the development of bone atrophy. In the present study, the relation of microvascular events in the bone marrow to the development of and recovery from bone atrophy was examined in rats treated with thiotepa, an antitumour drug derived from nitrogen mustards.
Material and methods Fifty female 5-week-old Wistar rats weighing initially 100-120 g were allowed free access to ordinary rat pellets and water. Thiotepa (1, I' ,1"-phosphinothioylidynetrisaziridine) was injected subcutaneously in a solution of 5 mg in 1 ml of physiological saline. The abdomen was opened through an upper midline incision under ether anaesthesia, 1, 3, 6 or 13 days after the injection (8 rats in each group). The abdominal aorta and the inferior vena cava were cannulated with polyethylene catheters. After heparinization, 100 ml of physiological saline was infused into the aorta for 15 min to wash out blood in the bone marrow, and 50 ml of 10 % buffered neutral formalin was infused (infusion pressure: 40-50 mm H 20). Then barium sulphate emulsion was injected into the inferior vena cava for easy microscopic demonstration of the sinusoids. The tibia was removed and fixed in 10 % buffered neutral formalin for 3 days, decalcified, embedded in paraffin, and cut lengthwise. Ten 5 11m sections were cut and stained with haemtoxylin and eosin. As controls, rats injected with 1 ml of physiological saline were killed immediately or 13 days after the injection (9 rats in each group). To determine volume percentages of trabecular bone, sinusoids and haematopoietic cells, we analysed the areas between the epiphyseal cartilage, cortical bone and diaphyseal cavity using a 121-point test grid at a 200-fold magnification (4 fields per section) (BAAK and OORT 1983). We analysed 40 fields, namely 4840 points, per tibia. Data are expressed as the mean ± S.D. and analysed statistically by Student's t test. The level of significance was P < 0.05 for all experiments. Exp Toxic Patho1 45 (1993) 2-3
129
Fig. 1. Tibial metaphysis of a control rat on 1st experimental day. H & E, X 200. There is no conspicuous change in haematopoietic tissue, sinusoids or trabecular bone. The sinusoids contain barium sulphate. Fig. 2. Tibial metaphysis of a rat 3 days after injection of thiotepa. H & E, X 200. The haematopoietic cells are markedly reduced, and the sinusoids severely dilated. There is no change in the number of sinusoids per unit area. Atrophy of trabecular bone is prominent. Fig. 3. Tibial metaphysis of a rat 13 days after injection of thiotepa. H & E, X 200. The haematopoietic cells regenerate, the sinusoids normalize, and the trabecular bone recovers from atrophy. 130
Exp Toxic Pathol 45 (1993) 2-3
70
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40
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~
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Days after injection Fig. 4. Changes in volume percentage of haematopoietic cells, sinusoids and trabecular bone in the tibial metaphysis of rats given thiotepa. Each point represents the mean for a group of 8 or 9 rats, and the standard deviations of mean values are indicated by vertical bars. ..!C a; <..I
32 .8 ± 7.3, respectively; on the 7th experimental day, 24.0 ± 6.3, 31.8 ± 6 .8, and 32.3 ± 7.0, respectively; and on the 14th experimental day, 24.9 ± 6.8 , 31.2 ± 5.9, and 31.5 ± 4 .2, respectively. In the rats injected with thiotepa, the body weight was 121 ± 6 g on the 1st experimental day, 129 ± 9 g on the 7th experimental day and 154 ± 8 g on the 14th experimental day. The body weight on the 7th experimental day did not significantly increase as compared with that on the 1st experimental day, because it was reduced 1 and 3 days after the injection. On the 14th experimental day, there was no significant difference in body weight between the control rats and the rats treated with thiotepa. The size of the tibia was closely related to the change in body weight. The haematopoietic cells in the bone marrow of the tibiae were abruptly reduced 1 day after the injection. However, they recovered rapidly starting 3 days after the injection and were more numerous than normal 13 days after the injection (figs. 2 and 3) . The sinusoids were markedly dilated 1 day after the injection, but normalized rapidly starting 3 days after the injection and were just below normal 13 days after the injection . There was no change in the number of sinusoids per unit area. The trabecular bone was gradually reduced after the injection, and then gradually recovered starting 6 days after the injection. The trabecular bone was thinned, but the numbers of osteocytes and osteoclasts were within the normal limits. The changes in the volume percentages of the haematopoietic cells, sinusoids and trabecular bone are shown in fig. 4. The relationships of volume percentages between the haematopoietic cells and the sinusoids and between the
N=50 Y'" 38.183- 0.152X r=-0.808
40
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Fig. 5. Relationship of volume percentages between haematopoietic cells and sinusoids in tibial metaphysis of rats.
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o~--~----~--~----~----~--~----~-
o
Results In the control rats, the body weight was 118 ± 6 g on the 1st experimental day , 140 ± 8 g on the 7th experimental day and 161 ± 7 g on the 14th experimental day . The tibia grew with the increase in body weight. The histological appearance of the tibiae was within the normal limits throughout the experiment (fig. 1). The volume percentages of the haematopoietic cells, sinusoids and trabecular bone on the 1st experimental day were 23.7 ± 6.0, 32.1 ± 6.9, and 9*
10
20
30
40
50
60
70
Volume percentage of sinusoids sinusoids and the trabecular bone were statistically significant, as shown in fig. 5 and 6, respectively. However, the relationship in volume percentages between the haematopoietic cells and the trabecular bone (fig. 7) was not statistically significant.
Discussion The present study shows that the administration of thiotepa induces a rapid decrease in haematopoietic cells and a marked Exp Toxic Pathol45 (1993) 2-3
131
50
N=50 Y- 43.191-0.4D7X r =-0.707
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Volume percentage of sinusoids Fig. 6. Relationship of volume percentages between sinusoids and trabecular bone in tibial metaphysis of rats. N=50 Y=6.680+0.331X r=0.306
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Voillme percentage Df trabecular bone Fig. 7. Relationship of volume percentages haematopoietic cells and trabecular bone in tibial metaphysis of rats.
dilatation of sinusoids and atrophy of trabecular bone in the metaphyses of the tibia of rats. Moreover, there were close relationships between the decrease in haematopoietic cells and the dilatation of sinusoids and between the dilatation of sinusoids and the decrease in trabecular bone. These findings suggest that atrophy of trabecular bone is related to the dilatation of sinusoids following a decrease in haematopoietic tissue. We believe that this bone atrophy is not apparent, because there was no difference in the size of the tibia between the 1st and the 7th experimental day. It is well known that dilatation of the capillaries and venules causes a reduction of the velocity of blood flow, sludging, augmentation of plasma skimming, margination of leukocytes and adhesion of leukocytes to the vessel wall. Accordingly, the dilatation of sinusoids may lead to these microcirculatory disturbances, and conse132
Exp Toxic Pathol 45 (1993) 2-3
quently may cause a decrease in the efficiency of exchange of nutrients and waste products between the sinusoids and the trabecular bone. It is thought that trabecular bone is maintained by diffusion of the substances, because trabecular bone has no Haversian system. Thus the dilatation of sinusoids following the decrease in haematopoietic cells may cause atrophy of trabecular bone. The direct effects of thiotepa on osteocytes or osteoblasts may cause bone atrophy, because thiotepa is an antitumour drug derived from nitrogen mustards and a suppressor of the bone marrow. In the present study, however, degeneration or necrosis of the osteocytes and osteoblasts was not seen in the trabecular or cortical bone of the tibia. These findings suggest that thiotepa has little or no direct effect on the atrophy of trabecular bone. The present study also demonstrates that the changes in the bone marrow induced by thiotepa are transient, that is, regeneration of haematopoietic cells and normalization of the dilated sinusoids start 3 days after the injection, and the atrophied trabecular bone gradually returns to normal starting 6 days after the injection. This recovery from atrophy of trabecular bone is thought to be not apparent, because there was no difference in the size of the tibia and in the volume percentage of trabecular bone between the control rats and the rats treated with thiotepa on the 14th experimental day. Moreover, there were close relationship between regeneration of haematopoietic cells and normalization of the diameter of sinusoids and between the normalization of sinusoids and atrophy of trabecular bone. These findings suggest that the normalization of the diameter of dilated sinusoids following the regeneration of haematopoietic cells repairs the microcirculatory disturbance of the sinusoids and leads to recovery from atrophy of trabecular bone. In conclusion, the present study implies that the maintenance of trabecular bone is closely related to the microcirculation of the bone marrow, that is, microcirculatory disturbance of the sinusoids causes atrophy of the trabecular bone, and the normalization of the microcirculation repairs the atrophy of trabecular bone.
References BAAK JPA, OORT J: A manual of morphometry in diagnostic pathology. Springer-Verlag Berlin-Heidelberg-New York-Tokyo 1983. FERNANDEZ DE VALDERRAMA JA, LITTLE K: Mechanisms involved in the osteoporotic process. J Bone Joint Surg 1965; 47B: 193. GEISER M, TRUETA J: Muscle action, bone rarefaction and bone formation. J Bone Joint Surg 1958; 4OB: 282-311. MCCLUGAGE SG, MCCUSKEY RS: Relationship of the microvascular system to bone resorption and growth in situ. Microvasc Res 1973; 6: 132-134.
SEMB H: Experimental disuse osteoporosis. l. Acid-base status in intramedullary blood from immobilized rabbit tibial bones. Acta Soc Med Upsal 1966a; 71: 83-95. SEMB H: Experimental disuse osteoporosis. III. Oxygen saturation and oxygen tension in intramedullary blood from immobilized rabbit tibial bones. Acta Soc Med Upsa11966b; 71: 96-107.
Exp Toxic Pathol 1993; 45: 133 Gustav Fischer Verlag lena
SHIBAYAMA Y, NISHIMOTO M, NAKATA K: Role of microenvironmental deterioration of the bone marrow in the development of bone atrophy in magnesium silicate-treated rats. Exp Toxic Pathol (in press). VERHAS M, MARTINELLO Y, MONE M, et al.: Demineralization and pathological physiology of the skeleton in paraplegic rats. Calcif Tissue Int 1980; 30: 83-90.
Book review
The Natural Immune System: The Macrophage Edited by CLAIRE E. LEWIS and JAMES O'D. MCGEE 423 pages. IRL Press at Oxford University Press, Oxford-New York-Tokyo 1992. Softcover. ISBN 0-19-963234-0. This book provides a presentation of all essential aspects of macrophages in health and disease on an up to date level. It is introduced by a general, wideranging contribution "The biology of macrophage" by M. 1. AUGER and J. A. Ross encompassing the macrophage heterogeneity and an overview about the role of mononuclear phagocytes in health and disease. The molecular basis of macrophage activation is discussed by D. O. ADAMS and T. A. HAMILTON: The activation of mononuclear phagocytes and its primary constituent base are quite complex, and the authors present a model of multiple genes and stimuli in macrophages. The capacity of macrophages to exert controls over the haematopoietic system - macrophages are a component of the haematopoietic stroma - is described by P. R. CROCKNER and G. MILON. The specialized cellular interactions between macrophages and haematopoietic cells which are mediated by the secretory capacity, specific receptors and ligands of the bone marrow macrophages provide insights into the macrophage functions in steady state haematopoiesis. - Three chapters deal with the role of macrophages in viral (H. E. GENDELMAN and P. S. MORAHAN), bacterial (D. P. SPEERT), and parasitic infection (M. D. SADICK). - The role of macrophages in immunodeficiency and autoimmunity is described and discussed by S. POLLACK and A. bTZIONI. In these cases the macrophage function may be impaired primarily, as the cause of the pathology, or secondarily, as a consequence of other immune cell
dysfunctions, facilitating the progression of the disease. - A contribution of R. C. REES and H. PARRY deals with the involvement of mononuclear phagocytes in the pathogenesis of malignant disease. The biological responses of monocytes and macrophages at various states of differentiation and activation are described in this chapter, and it is discussed that some are tumoricidal, but others may support the tumor cell growth by secretion of growth factors and/or suppression of the antitumor respnoses of infiltrating lymphocytes. - D. V. PARUMS describes and discusses the role of the macrophage in cardiovascular disease, especially its function in the genesis of atherosclerotic plaque. Finally, the functions of the resident macrophages of the central nervous system, known as microglia, are presented by V. H. PERRY and L. J. LAWSON. - These cells are sensitive to various pathological insults but their functions in the normal and injured CNS are largely unknown. The contributions, all written by authors of recognized authority in their fields, provide an excellent overview with detailed information on a up to date level. The editors and authors succeeded in presenting one of the most important areas of modem cell biology and medicine in an exciting manner. This is why not only immunologists and researchers in immunology but also advanced students as well as physicians, faced with immunological diseases, are highly interested in this book. It can be recommended without any restriction. F. BOLCK, Jena
Exp Toxic Pathol45 (1993) 2-3
133
Department of Pathology, Osaka Medical College, Takatsuki, Osaka, Japan
Microvascular events in bone marrow related to development of and recovery from bone atrophy in thiotepa-treated rats Y. SHIBAYAMA, M. NISHIMOTO and K. NAKATA With 7 figures Received: May 27, 1992; Revised: August 11, 1992; Accepted: August 28, 1992
Address for correspondence: Dr. Y. SHIBAYAMA, Department of Pathology, Osaka Medical College, Daigaku-Cho, Takatsuki City, Osaka, Japan.
Key words: Bone atrophy; Recovery from bone atrophy; Microcirculation of bone marrow; Thiotepa; Bone morphometry.
Summary To clarify the relationship of microvascular events in the bone marrow to the development of and the recovery from bone atrophy, we examined quantitatively and qualitatively trabecular bone, sinusoids and haematopoietic tissue in the metaphysis of the tibia of rats given thiotepa, an antitumour drug derived from nitrogen mustards. The administration of thiotepa rapidly reduced the number of haematopoietic cells causing significant dilatation of the sinusoids and atrophy of the trabecular bone 1 day after the injection. However, these changes were transient; regeneration of haematopoietic cells and normalization of the dilated sinusoids started 3 days after the injection, and the atrophied trabecular bone gradually returned to normal starting 6 days after the injection. These results imply that an extreme decrease in velocity and margination of sinusoidal blood flow following marked dilatation due to a decrease in haematopoietic cells cause atrophy ofthe trabecular bone, and that normalization of the sinusoidal blood flow following regeneration of haematopoietic cells leads to recovery from atrophy of trabecular bone.
Introduction In an earlier study we offered a hypothesis that deterioration of the microenvironment in the bone marrow, that is, the disturbance of exchange of nutrients and waste products due to circulatory changes in the sinusoids, is a cause of atrophy of trabecular bone (SHIBAYAMA et al. in press). Some investigators have reported prominent blood vessel proliferation and dilated sinusoids in the bone marrow as well as an increase in blood flow and in the velocity of blood flow in the venules of the bone marrow in immobilized animals with bone atrophy (FERNANDEZ DE V ALDERRAMA and LITTLE 1965; GEISER and TRUETA 1958; MCCLUGAGE and MCCUSKEY 1973; SEMB 1966a; SEMB 1966b; VERHAS et al. 1980). Indeed, in autopsy cases we sometimes see dilatation of the sinusoids and bone atrophy. However, it has not been clear 9
that circulatory changes lead to the development of bone atrophy. In the present study, the relation of microvascular events in the bone marrow to the development of and recovery from bone atrophy was examined in rats treated with thiotepa, an antitumour drug derived from nitrogen mustards.
Material and methods Fifty female 5-week-old Wistar rats weighing initially 100-120 g were allowed free access to ordinary rat pellets and water. Thiotepa (1, I' ,1"-phosphinothioylidynetrisaziridine) was injected subcutaneously in a solution of 5 mg in 1 ml of physiological saline. The abdomen was opened through an upper midline incision under ether anaesthesia, 1, 3, 6 or 13 days after the injection (8 rats in each group). The abdominal aorta and the inferior vena cava were cannulated with polyethylene catheters. After heparinization, 100 ml of physiological saline was infused into the aorta for 15 min to wash out blood in the bone marrow, and 50 ml of 10 % buffered neutral formalin was infused (infusion pressure: 40-50 mm H 20). Then barium sulphate emulsion was injected into the inferior vena cava for easy microscopic demonstration of the sinusoids. The tibia was removed and fixed in 10 % buffered neutral formalin for 3 days, decalcified, embedded in paraffin, and cut lengthwise. Ten 5 11m sections were cut and stained with haemtoxylin and eosin. As controls, rats injected with 1 ml of physiological saline were killed immediately or 13 days after the injection (9 rats in each group). To determine volume percentages of trabecular bone, sinusoids and haematopoietic cells, we analysed the areas between the epiphyseal cartilage, cortical bone and diaphyseal cavity using a 121-point test grid at a 200-fold magnification (4 fields per section) (BAAK and OORT 1983). We analysed 40 fields, namely 4840 points, per tibia. Data are expressed as the mean ± S.D. and analysed statistically by Student's t test. The level of significance was P < 0.05 for all experiments. Exp Toxic Patho1 45 (1993) 2-3
129
Fig. 1. Tibial metaphysis of a control rat on 1st experimental day. H & E, X 200. There is no conspicuous change in haematopoietic tissue, sinusoids or trabecular bone. The sinusoids contain barium sulphate. Fig. 2. Tibial metaphysis of a rat 3 days after injection of thiotepa. H & E, X 200. The haematopoietic cells are markedly reduced, and the sinusoids severely dilated. There is no change in the number of sinusoids per unit area. Atrophy of trabecular bone is prominent. Fig. 3. Tibial metaphysis of a rat 13 days after injection of thiotepa. H & E, X 200. The haematopoietic cells regenerate, the sinusoids normalize, and the trabecular bone recovers from atrophy. 130
Exp Toxic Pathol 45 (1993) 2-3
70
60
50
~
... ... ...15
.!:"!
Haematopoietic cells
40
=
~
c.
<3
30
>-
Trabecular bone Sinusoid s
o1
13
Days after injection Fig. 4. Changes in volume percentage of haematopoietic cells, sinusoids and trabecular bone in the tibial metaphysis of rats given thiotepa. Each point represents the mean for a group of 8 or 9 rats, and the standard deviations of mean values are indicated by vertical bars. ..!C a; <..I
32 .8 ± 7.3, respectively; on the 7th experimental day, 24.0 ± 6.3, 31.8 ± 6 .8, and 32.3 ± 7.0, respectively; and on the 14th experimental day, 24.9 ± 6.8 , 31.2 ± 5.9, and 31.5 ± 4 .2, respectively. In the rats injected with thiotepa, the body weight was 121 ± 6 g on the 1st experimental day, 129 ± 9 g on the 7th experimental day and 154 ± 8 g on the 14th experimental day. The body weight on the 7th experimental day did not significantly increase as compared with that on the 1st experimental day, because it was reduced 1 and 3 days after the injection. On the 14th experimental day, there was no significant difference in body weight between the control rats and the rats treated with thiotepa. The size of the tibia was closely related to the change in body weight. The haematopoietic cells in the bone marrow of the tibiae were abruptly reduced 1 day after the injection. However, they recovered rapidly starting 3 days after the injection and were more numerous than normal 13 days after the injection (figs. 2 and 3) . The sinusoids were markedly dilated 1 day after the injection, but normalized rapidly starting 3 days after the injection and were just below normal 13 days after the injection . There was no change in the number of sinusoids per unit area. The trabecular bone was gradually reduced after the injection, and then gradually recovered starting 6 days after the injection. The trabecular bone was thinned, but the numbers of osteocytes and osteoclasts were within the normal limits. The changes in the volume percentages of the haematopoietic cells, sinusoids and trabecular bone are shown in fig. 4. The relationships of volume percentages between the haematopoietic cells and the sinusoids and between the
N=50 Y'" 38.183- 0.152X r=-0.808
40
~ CO>
'0 "'-
... ...
oS
..
30
. ..
E
--... CO>
..c o
~
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.
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:- 10
Fig. 5. Relationship of volume percentages between haematopoietic cells and sinusoids in tibial metaphysis of rats.
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.••,.I .
:>
o~--~----~--~----~----~--~----~-
o
Results In the control rats, the body weight was 118 ± 6 g on the 1st experimental day , 140 ± 8 g on the 7th experimental day and 161 ± 7 g on the 14th experimental day . The tibia grew with the increase in body weight. The histological appearance of the tibiae was within the normal limits throughout the experiment (fig. 1). The volume percentages of the haematopoietic cells, sinusoids and trabecular bone on the 1st experimental day were 23.7 ± 6.0, 32.1 ± 6.9, and 9*
10
20
30
40
50
60
70
Volume percentage of sinusoids sinusoids and the trabecular bone were statistically significant, as shown in fig. 5 and 6, respectively. However, the relationship in volume percentages between the haematopoietic cells and the trabecular bone (fig. 7) was not statistically significant.
Discussion The present study shows that the administration of thiotepa induces a rapid decrease in haematopoietic cells and a marked Exp Toxic Pathol45 (1993) 2-3
131
50
N=50 Y- 43.191-0.4D7X r =-0.707
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Volume percentage of sinusoids Fig. 6. Relationship of volume percentages between sinusoids and trabecular bone in tibial metaphysis of rats. N=50 Y=6.680+0.331X r=0.306
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Voillme percentage Df trabecular bone Fig. 7. Relationship of volume percentages haematopoietic cells and trabecular bone in tibial metaphysis of rats.
dilatation of sinusoids and atrophy of trabecular bone in the metaphyses of the tibia of rats. Moreover, there were close relationships between the decrease in haematopoietic cells and the dilatation of sinusoids and between the dilatation of sinusoids and the decrease in trabecular bone. These findings suggest that atrophy of trabecular bone is related to the dilatation of sinusoids following a decrease in haematopoietic tissue. We believe that this bone atrophy is not apparent, because there was no difference in the size of the tibia between the 1st and the 7th experimental day. It is well known that dilatation of the capillaries and venules causes a reduction of the velocity of blood flow, sludging, augmentation of plasma skimming, margination of leukocytes and adhesion of leukocytes to the vessel wall. Accordingly, the dilatation of sinusoids may lead to these microcirculatory disturbances, and conse132
Exp Toxic Pathol 45 (1993) 2-3
quently may cause a decrease in the efficiency of exchange of nutrients and waste products between the sinusoids and the trabecular bone. It is thought that trabecular bone is maintained by diffusion of the substances, because trabecular bone has no Haversian system. Thus the dilatation of sinusoids following the decrease in haematopoietic cells may cause atrophy of trabecular bone. The direct effects of thiotepa on osteocytes or osteoblasts may cause bone atrophy, because thiotepa is an antitumour drug derived from nitrogen mustards and a suppressor of the bone marrow. In the present study, however, degeneration or necrosis of the osteocytes and osteoblasts was not seen in the trabecular or cortical bone of the tibia. These findings suggest that thiotepa has little or no direct effect on the atrophy of trabecular bone. The present study also demonstrates that the changes in the bone marrow induced by thiotepa are transient, that is, regeneration of haematopoietic cells and normalization of the dilated sinusoids start 3 days after the injection, and the atrophied trabecular bone gradually returns to normal starting 6 days after the injection. This recovery from atrophy of trabecular bone is thought to be not apparent, because there was no difference in the size of the tibia and in the volume percentage of trabecular bone between the control rats and the rats treated with thiotepa on the 14th experimental day. Moreover, there were close relationship between regeneration of haematopoietic cells and normalization of the diameter of sinusoids and between the normalization of sinusoids and atrophy of trabecular bone. These findings suggest that the normalization of the diameter of dilated sinusoids following the regeneration of haematopoietic cells repairs the microcirculatory disturbance of the sinusoids and leads to recovery from atrophy of trabecular bone. In conclusion, the present study implies that the maintenance of trabecular bone is closely related to the microcirculation of the bone marrow, that is, microcirculatory disturbance of the sinusoids causes atrophy of the trabecular bone, and the normalization of the microcirculation repairs the atrophy of trabecular bone.
References BAAK JPA, OORT J: A manual of morphometry in diagnostic pathology. Springer-Verlag Berlin-Heidelberg-New York-Tokyo 1983. FERNANDEZ DE VALDERRAMA JA, LITTLE K: Mechanisms involved in the osteoporotic process. J Bone Joint Surg 1965; 47B: 193. GEISER M, TRUETA J: Muscle action, bone rarefaction and bone formation. J Bone Joint Surg 1958; 4OB: 282-311. MCCLUGAGE SG, MCCUSKEY RS: Relationship of the microvascular system to bone resorption and growth in situ. Microvasc Res 1973; 6: 132-134.
SEMB H: Experimental disuse osteoporosis. l. Acid-base status in intramedullary blood from immobilized rabbit tibial bones. Acta Soc Med Upsal 1966a; 71: 83-95. SEMB H: Experimental disuse osteoporosis. III. Oxygen saturation and oxygen tension in intramedullary blood from immobilized rabbit tibial bones. Acta Soc Med Upsa11966b; 71: 96-107.
Exp Toxic Pathol 1993; 45: 133 Gustav Fischer Verlag lena
SHIBAYAMA Y, NISHIMOTO M, NAKATA K: Role of microenvironmental deterioration of the bone marrow in the development of bone atrophy in magnesium silicate-treated rats. Exp Toxic Pathol (in press). VERHAS M, MARTINELLO Y, MONE M, et al.: Demineralization and pathological physiology of the skeleton in paraplegic rats. Calcif Tissue Int 1980; 30: 83-90.
Book review
The Natural Immune System: The Macrophage Edited by CLAIRE E. LEWIS and JAMES O'D. MCGEE 423 pages. IRL Press at Oxford University Press, Oxford-New York-Tokyo 1992. Softcover. ISBN 0-19-963234-0. This book provides a presentation of all essential aspects of macrophages in health and disease on an up to date level. It is introduced by a general, wideranging contribution "The biology of macrophage" by M. 1. AUGER and J. A. Ross encompassing the macrophage heterogeneity and an overview about the role of mononuclear phagocytes in health and disease. The molecular basis of macrophage activation is discussed by D. O. ADAMS and T. A. HAMILTON: The activation of mononuclear phagocytes and its primary constituent base are quite complex, and the authors present a model of multiple genes and stimuli in macrophages. The capacity of macrophages to exert controls over the haematopoietic system - macrophages are a component of the haematopoietic stroma - is described by P. R. CROCKNER and G. MILON. The specialized cellular interactions between macrophages and haematopoietic cells which are mediated by the secretory capacity, specific receptors and ligands of the bone marrow macrophages provide insights into the macrophage functions in steady state haematopoiesis. - Three chapters deal with the role of macrophages in viral (H. E. GENDELMAN and P. S. MORAHAN), bacterial (D. P. SPEERT), and parasitic infection (M. D. SADICK). - The role of macrophages in immunodeficiency and autoimmunity is described and discussed by S. POLLACK and A. bTZIONI. In these cases the macrophage function may be impaired primarily, as the cause of the pathology, or secondarily, as a consequence of other immune cell
dysfunctions, facilitating the progression of the disease. - A contribution of R. C. REES and H. PARRY deals with the involvement of mononuclear phagocytes in the pathogenesis of malignant disease. The biological responses of monocytes and macrophages at various states of differentiation and activation are described in this chapter, and it is discussed that some are tumoricidal, but others may support the tumor cell growth by secretion of growth factors and/or suppression of the antitumor respnoses of infiltrating lymphocytes. - D. V. PARUMS describes and discusses the role of the macrophage in cardiovascular disease, especially its function in the genesis of atherosclerotic plaque. Finally, the functions of the resident macrophages of the central nervous system, known as microglia, are presented by V. H. PERRY and L. J. LAWSON. - These cells are sensitive to various pathological insults but their functions in the normal and injured CNS are largely unknown. The contributions, all written by authors of recognized authority in their fields, provide an excellent overview with detailed information on a up to date level. The editors and authors succeeded in presenting one of the most important areas of modem cell biology and medicine in an exciting manner. This is why not only immunologists and researchers in immunology but also advanced students as well as physicians, faced with immunological diseases, are highly interested in this book. It can be recommended without any restriction. F. BOLCK, Jena
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