Histological differences in bones of rats treated with sodium fluoride (NaF) and sodium monofluorophosphate (MFP)

Abstracts / Bone 45 (2009) S148–S157

S153

Dual hip densitometry: Analysis of densitometric and geometrical differences H. Claus Hermberg, M. Lozano, M. Rey, M. Pozzo Endocrinology Division, Hospital Alemán, Buenos Aires, Argentina

tion of CaG in the drinking water abolished tetany, but not under anesthesia. 3. ½ PX is a model of transitory severe hypocalcemia. 4. The intramuscular administration of CaG increased survival during general anesthesia.

Bone mineral density (BMD) of both femurs is often requested in spite of that World Health Organization does not recommend it for assessment of densitometric categories. We used data of patients who realized dual femur densitometry to analyze the variations in densitometric and geometrical properties between both hips. Materials and methods: BMD was measured with DXA (Lunar Prodigy). BMD (mg/cm2) disparities of femoral neck and total hip were analyzed by Z score. Differences in BMD, bone mineral content (BMC, g), area (A, cm2), cross-sectional moment of inertia (CSMI, mm4), hip axis length (HAL, mm), hip axis/diaphysis axis angle (angle, degrees), and calculated volumetric BMD (vBMD, g/cm3) were computed by subtracting the left hip values to those of the right. Results: Median (upper quartile) BMD disparities in Z score were femoral neck 0.28 (0.4) and total hip 0.2 (0.3). No woman had a difference higher than 0.8. The following significant differences from null (reference value) were observed in the neck (mean ± SD): A = 0.074 ± 0.16, Vol = 0.264 ± 0.69 (both p < 0.001), CSMI = 313 ± 1343 (p = 0.036), and marginal significant vBMD = −0.007 ± 0.03 (p=0.051), CMO = 0.051 ± 0.25 (p=0.06). Bigger A in the right femoral neck was observed in 58 women (68%), significantly higher than expected if the distribution were random (p < 0.001). Conclusions: Little BMD variations between both hips were observed. Right femoral neck was modestly bigger (A) and showed a trend to higher BMC. Since both have opposite effects on the determination of BMD, BMD did not show significant difference, whereas CSMI, which is positively influenced by them, did.

doi:10.1016/j.bone.2009.08.032

doi:10.1016/j.bone.2009.08.031

Calcemia and tetany in hypocalcemic models in the rat M. Lupo, A. Rigalli Bone Biology and Mineral Metabolism Laboratory, Argentina Low PTH levels decrease bone remodeling and calcemia. This situation can be obtained by ablation of either thyroid and parathyroid glands (TPTX) or parathyroid glands (PX). Both surgeries produce calcemia lower than 7.5 mg/dl. After the mentioned surgeries, hypocalcemia and tetany make difficult the follow-up of rats under treatments and surgeries. The objective of this work was the development of hypocalcemic models that avoid tetany. After PX, TPTX and ablation of one parathyroid gland (1/2PX), calcemia (before and 5 and 20 days after surgery), tetany, and survival were assessed. Results were expressed as mean ± SEM and differences were considered significant when p < 0.05. Experimental groups (n = 8 each): G1: PX, G2: PX + calcium gluconate (CaG) in the drinking water. After 5 days rats of G2 were subjected to general anesthesia and divided into as follows: G2a, without treatment, and G2b, with intramuscular CaG administration. G3, PX + CaG in the drinking water + water without CaG; G4, 1/2PX + CaG in the drinking water; G5, TPTX. Calcemia (mg/dl) before surgery was not different among groups. Calcemia after 5 days was lower in all groups when compared to the day of surgery (G1: 4.8 ± 0.7, G2: 7.6 ± 0.8, G2a: 7.2 ± 0.5, G2b: 7.7 ± 1.3, G3: 5.9 ± 0.8, G4: 3.5 ± 4.9, G5: 7.6 ± 0.3). Rats of G1 had tetany, which was not present in the other groups. G2a and G2b had tetany after anesthesia, which produced 100% of death in rats of G2a. The intramuscular injection of CaG in G2b produced 100% of survival. Calcemia at day 5 were lower in G1 and G4 compared to the other groups. Conclusions: 1. PX and 1/2PX produced a more severe hypocalcemia than TPTX. 2. The administra-

Histological differences in bones of rats treated with sodium fluoride (NaF) and sodium monofluorophosphate (MFP) L.R. Brun, S.M. Roma, F. Pérez, A. Rigalli Bone Biology and Mineral Metabolism Laboratory, Argentina NaF and MFP increase bone mass but the quality of bones under both treatment have not been compared. The objective of this work was to evaluate the quality of bone of rats under treatment for 30 days with 80 μmol of NaF (n = 8) or MFP (n = 8) in 21-day-old female rats. The right tibia was subjected to histomorphometric and histopathologic analysis of trabecular bone. Bone volume (BV%), trabecular number (Tn), and trabecular thickness (Tt) were measured. Cellular proliferation, organization, and inflammation were evaluated simultaneously. Endosteal and periosteal perimeters were measured on the diaphysis of femur. BV% (mean ± SEM) was higher in NaF and MFP when compared with controls (C: 22.1 ± 2.7, NaF: 35.2 ± 8.2, MFP: 33.3 ± 7.1). The same result was observed in Tt and Tn. Periosteal and endosteal perimeters were higher in MFP compared with C and NaF. The bone histological appearance NaFtreated rats, showed increased cellularity in the bone marrow and in bone, irregular trabeculae with unevenly distributed osteocytes and reactive osteoblasts, arrayed in two or more layers, with conspicuous osteoclasts, indicating a disorganized and immature cancellous bone structure. Multiple foci of acute inflammation and peritrabecular bands of fibrosis was also noticeable. Rats treated with MFP showed prominent bone formation but in a more organized fashion, with osteoblasts disposed in a continuous layer, one cell thick, lacking inflammatory changes and fibrosis. Conclusions: NaF and MFP increased BV% as a consequence of the increase in Tn and Tt. In the case of NaF inflammation, fibrosis, disorganized, and immature bone were observed. This pattern was not present in MFP treated rats. At the cortical level, MFP increased the sectional area of femoral diaphysis. doi:10.1016/j.bone.2009.08.033

Osteoclastic recruitment in bisphosphonates-treated animals and the relation with splenic and medullary macrophages N.D. Escudero, N.F. Mina, P.M. Mandalunis Department of Histology and Embryology, School of Dentistry, University of Buenos Aires, Argentina Antiresorptive effects of bisphosphonates (BPs) have been extensively studied. However, in vivo data regarding the osteoclast (Oc) and other cells of the mononuclear phagocytic system (MPS) remains controversial. The aim of this work was to study Oc recruitment, number, morphology, and its association with the macrophage population in animals treated with two BPs: alendronate and olpadronate (Gador SA). Wistar rats were divided into three groups: ALN: received alendronate; OPD: received olpadronate; both in an i.p. dose of 0.3 mg/kg/wk during 5 weeks. The sham group received vehicle. All animals received 5-bromo-2-deoxyuridine i.p. (BrdU; 0.1 mg/g bw). Within each experimental group, animals were divided into sub-groups according the day of BrdU administration: day 28 or 34. After sacrifice, spleen and femur were processed for ED1 and BrdU IHCh detection. Data were analyzed statistically. Femur:Oc