- Email: [email protected]
Bone remodeling and silicon deficiency in rats
S8
ABSTRACTS / Bone 40 (2007) S1–S17
Bone remodeling and silicon deficiency in rats Steimetz T, Katok K, Gorustovich A, Krieger ML, Nielsen H Forrest, Guglielmotti MB. Department of Oral Pathology, School of Dentistry, University of Buenos Aires, National Research Council United States Department of Agriculture, Grand Forks, ND, USA. Alveolar bone undergoes continuous remodeling to meet physiologic and functional demands. The aim of the present work was to evaluate histologically and histomorphometrically the effect of silicon deficiency on bone modeling and remodeling in the periodontal cortical plate. Two groups of weaning male Wistar rats (aged 21 days) were used: Control Group (CG n = 10) fed a basal diet supplemented with 35 mg Si/kg diet; Experimental Group (EG n = 8) fed a silicon-deficient diet (2 mg Si/Kg diet). All the rats were euthanized at 30 days. The mandibles were resected, fixed, radiographed, processed, and embedded in paraffin. Buccolingually oriented sections at the level of the mesial root of the first molar were obtained, and stained with H&E. The following parameters were measured: percentage of osteoblast (ObS), quiescent (QS) and eroded (ES) bone surfaces. Histology: EG rats showed a decrease in ObS in both cortical plates, an increase in ES in the buccal cortical plate and in QS in the lingual cortical plate. Histomorphometry: EG rats showed a decrease in ObS. (GC = 45%, GE = 30%) (p < 0.001) concomitant with an increase in ES. (GC = 16%, GE = 28%) (p < 0.005), and no significant differences in QS (GC = 39%, GE = 42%) in the buccal cortical plate, and a decrease in ObS (GC = 62%, GE = 48%) (p < 0.001) concomitant with an increase in QS (GC = 38%, GE = 52%) (p < 0.001) in the lingual cortical plate. Our findings show the importance of an adequate supply of silicon for bone remodeling, especially for bone formation. UBACYT 020, CONICET PIP 6042, USDA 585450-3-F094. doi:10.1016/j.bone.2006.12.024
Rat intestinal alkaline phosphatase (IAP) levels at different intestinal calcium concentrations. Experiments with intestinal everted sacs Brun L.R.M, Brance M.L, de Candia L, Traverso A, Rigalli A. Bone Biology Lab. School of Medicine. Rosario University. Argentine. Calcium (Ca) in vitro modifies biphasically IAP activity. IAP activity increases up to Ca 10 mM and then decreases. The objective of this work was to investigate the effect of luminal Ca on the serum and luminal concentrations of IAP. Everted intestine experiments were carried out with three segments of 3 cm each from the pylorous, in caudal direction. Fasted female 200-gram rats strain IIM/FM substrain m were used. Intestinal mucose were exposed to the following solution (Smucose): Tris 1 mM, MgCl2 1 mM, glucose 160 mM, Ca 1 mM, 10 mM or 100 mM and the serosal side were exposed to the same solution without Ca (Sserosa). Samples were obtained from Smucose at
0, 10, 20, 30, 50, 65 years 80 min and from the serosal solution at the end of the experiment. IAP concentration was measured by dot blot in Smucose and by Western Blot in Sserosa. Values were expressed as integrated optical density units (IOD). Guinea Pig anti-rat IAP primary antibody, anti-guinea pig immunoglobulin G horseradish peroxidase-conjugated secondary antibody and 3amino-9-ethyl carbazole as substrate were used. Results are expressed as mean ± SEM. IAP concentration in Smucose increased significantly along the experiment (Ca = 1 mM 4.3 ± 0.6, Ca = 10 mM 3.8 ± 0.7, Ca = 100 mM 1.0 ± 0.2 IOD unit/min p < 0.0001). This increase followed an inverse relationship with Ca concentration (p < 0.0001). A direct relationship between IAP concentration in Sserosa and luminal Ca concentrations was observed (Ca = 1 mM 39.2 ± 3.5, Ca = 10 mM 66.7 ± 7.5, Ca = 100 mM 88.7 ± 8.2 IOD unit/min p < 0.0001). Conclusion: The release of IAP to serosa and mucose followed a direct and inverse relationship with Ca concentrations, respectively. doi:10.1016/j.bone.2006.12.025
Bone mass increase and mineralization in rats treated with sodium monofluorophosphate (MFP) and sodium fluoride (NaF) Brun LRM, Rigalli A. Bone Biology Laboratory School of Medicine, Rosario University, Argentina. Fluoride produces differentiation and proliferation of osteoblasts, and as a consequence it increases bone mass. This effect is consequence of fluoride inhibitory effect of an acid phosphatase involved in signalling pathways of growth factors. The quality of bone formed under fluoride stimulus is still open to debate. On the other hand, MFP would act through the described mechanism and probably through another mechanism that involved Wnt cascade. MFP binds to α2-macroglobulin and is cleared from plasma for LRP receptor, which acts together with Frizzled receptor in Wnt signalling. Even though at equivalent doses both drugs induce similar increase in bone mass, after stopping MFP treatment, bone mass remains higher than NaF treated rats. The objective of this work was to study the effect of MFP and NaF on bone mass and mineralization. Female 21-day-old rats strain IIM/FM drank for 100 days water with 5 mM NaF (n = 40), 5 mM MFP (n = 40) or distilled water (Controls, n = 40) drank. Food conversion efficiency (body weight daily change/daily food intake) and bone mass (weight of whole skeleton, gram) were measured. Mineralization was measured through the relation: weight of bone ashes/weight of dry bone. MFP and NaF treatment did not modify efficiency of animals. Both MFP and NaF treatment increased the asymptotic bone mass (C = 9.24 ± 0.3160, MFP = 10.56 ± 0.4529, NaF = 10.75 ± 0.5341). Mineralization increased in controls as well as in MFP treated rats, without differences between groups. On the contrary, rats treated with NaF did not show increased in mineralization of bones. Conclusion: MFP produces increased in bone mass without changing mineralization of bone tissue.
ABSTRACTS / Bone 40 (2007) S1–S17
Bone remodeling and silicon deficiency in rats Steimetz T, Katok K, Gorustovich A, Krieger ML, Nielsen H Forrest, Guglielmotti MB. Department of Oral Pathology, School of Dentistry, University of Buenos Aires, National Research Council United States Department of Agriculture, Grand Forks, ND, USA. Alveolar bone undergoes continuous remodeling to meet physiologic and functional demands. The aim of the present work was to evaluate histologically and histomorphometrically the effect of silicon deficiency on bone modeling and remodeling in the periodontal cortical plate. Two groups of weaning male Wistar rats (aged 21 days) were used: Control Group (CG n = 10) fed a basal diet supplemented with 35 mg Si/kg diet; Experimental Group (EG n = 8) fed a silicon-deficient diet (2 mg Si/Kg diet). All the rats were euthanized at 30 days. The mandibles were resected, fixed, radiographed, processed, and embedded in paraffin. Buccolingually oriented sections at the level of the mesial root of the first molar were obtained, and stained with H&E. The following parameters were measured: percentage of osteoblast (ObS), quiescent (QS) and eroded (ES) bone surfaces. Histology: EG rats showed a decrease in ObS in both cortical plates, an increase in ES in the buccal cortical plate and in QS in the lingual cortical plate. Histomorphometry: EG rats showed a decrease in ObS. (GC = 45%, GE = 30%) (p < 0.001) concomitant with an increase in ES. (GC = 16%, GE = 28%) (p < 0.005), and no significant differences in QS (GC = 39%, GE = 42%) in the buccal cortical plate, and a decrease in ObS (GC = 62%, GE = 48%) (p < 0.001) concomitant with an increase in QS (GC = 38%, GE = 52%) (p < 0.001) in the lingual cortical plate. Our findings show the importance of an adequate supply of silicon for bone remodeling, especially for bone formation. UBACYT 020, CONICET PIP 6042, USDA 585450-3-F094. doi:10.1016/j.bone.2006.12.024
Rat intestinal alkaline phosphatase (IAP) levels at different intestinal calcium concentrations. Experiments with intestinal everted sacs Brun L.R.M, Brance M.L, de Candia L, Traverso A, Rigalli A. Bone Biology Lab. School of Medicine. Rosario University. Argentine. Calcium (Ca) in vitro modifies biphasically IAP activity. IAP activity increases up to Ca 10 mM and then decreases. The objective of this work was to investigate the effect of luminal Ca on the serum and luminal concentrations of IAP. Everted intestine experiments were carried out with three segments of 3 cm each from the pylorous, in caudal direction. Fasted female 200-gram rats strain IIM/FM substrain m were used. Intestinal mucose were exposed to the following solution (Smucose): Tris 1 mM, MgCl2 1 mM, glucose 160 mM, Ca 1 mM, 10 mM or 100 mM and the serosal side were exposed to the same solution without Ca (Sserosa). Samples were obtained from Smucose at
0, 10, 20, 30, 50, 65 years 80 min and from the serosal solution at the end of the experiment. IAP concentration was measured by dot blot in Smucose and by Western Blot in Sserosa. Values were expressed as integrated optical density units (IOD). Guinea Pig anti-rat IAP primary antibody, anti-guinea pig immunoglobulin G horseradish peroxidase-conjugated secondary antibody and 3amino-9-ethyl carbazole as substrate were used. Results are expressed as mean ± SEM. IAP concentration in Smucose increased significantly along the experiment (Ca = 1 mM 4.3 ± 0.6, Ca = 10 mM 3.8 ± 0.7, Ca = 100 mM 1.0 ± 0.2 IOD unit/min p < 0.0001). This increase followed an inverse relationship with Ca concentration (p < 0.0001). A direct relationship between IAP concentration in Sserosa and luminal Ca concentrations was observed (Ca = 1 mM 39.2 ± 3.5, Ca = 10 mM 66.7 ± 7.5, Ca = 100 mM 88.7 ± 8.2 IOD unit/min p < 0.0001). Conclusion: The release of IAP to serosa and mucose followed a direct and inverse relationship with Ca concentrations, respectively. doi:10.1016/j.bone.2006.12.025
Bone mass increase and mineralization in rats treated with sodium monofluorophosphate (MFP) and sodium fluoride (NaF) Brun LRM, Rigalli A. Bone Biology Laboratory School of Medicine, Rosario University, Argentina. Fluoride produces differentiation and proliferation of osteoblasts, and as a consequence it increases bone mass. This effect is consequence of fluoride inhibitory effect of an acid phosphatase involved in signalling pathways of growth factors. The quality of bone formed under fluoride stimulus is still open to debate. On the other hand, MFP would act through the described mechanism and probably through another mechanism that involved Wnt cascade. MFP binds to α2-macroglobulin and is cleared from plasma for LRP receptor, which acts together with Frizzled receptor in Wnt signalling. Even though at equivalent doses both drugs induce similar increase in bone mass, after stopping MFP treatment, bone mass remains higher than NaF treated rats. The objective of this work was to study the effect of MFP and NaF on bone mass and mineralization. Female 21-day-old rats strain IIM/FM drank for 100 days water with 5 mM NaF (n = 40), 5 mM MFP (n = 40) or distilled water (Controls, n = 40) drank. Food conversion efficiency (body weight daily change/daily food intake) and bone mass (weight of whole skeleton, gram) were measured. Mineralization was measured through the relation: weight of bone ashes/weight of dry bone. MFP and NaF treatment did not modify efficiency of animals. Both MFP and NaF treatment increased the asymptotic bone mass (C = 9.24 ± 0.3160, MFP = 10.56 ± 0.4529, NaF = 10.75 ± 0.5341). Mineralization increased in controls as well as in MFP treated rats, without differences between groups. On the contrary, rats treated with NaF did not show increased in mineralization of bones. Conclusion: MFP produces increased in bone mass without changing mineralization of bone tissue.