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Bone loss due to estrogen suppression and unloading: comparison of isolated and combined experimental models to study osteoporosis


Pharmacy & Pharmacology International Journal
Patrícia Sena Pinheiro,1 Ariane Zamarioli,2 Ana Paula Macedo Neto,3 Manoel Damião,3 Lustosa Lygia Paccini,4 Antonio Carlos Shimano2

Abstract

Objective: To compare compare two experimental models of bone loss induction; by estrogen deficiency and mechanical overload and to assess the effects of osteoporosis in resistance, density and microstructure of bone (femur, tibia) in rats.
Design: Seventy Wistar rats (180-200g) were divided into seven groups (n = 10 per group) and three groups for 21 days (A) and four groups analyzed for 90 days (B) C (A): control group , Susp (A): suspension by the tail, OVX + Susp (A): ovariectomy and tail suspension; C (B): control group; OVX (B): ovariectomy, C + Susp (B): control and suspension by the tail, OVX + Susp (B): ovariectomy and tail suspension. The animals in group A were killed 21 days and group B with 90 days. At the end of the trial period, the bones were subjected to densitometric, macroscopic, biomechanical and histomorphometric analysis. The level of statistical significance was 5%. All analyzes showed significant reduction in bone quality.
Results: The animals of groups Susp (A) and OVX + Susp (A) showed a reduction of bone mass and circumference. The mechanical strength, femur and tibia BMD in group OVX + Susp (B) and OVX group + Susp (A) reduced more significant compared to the suspension by the tail. Bone microarchitecture showed a significant reduction in the OVX group + Susp (A), showing loss of trabecular. Already in animals 90 days ovariectomy association and suspension by the tail, caused reduction bone microarchitecture.
Conclusion: concluded that both ovariectomy as suspension by the tail, proved to be efficient experimental models for the study of bone loss.

Keywords

bone, osteoporosis, ovariectomy, hindlimb suspension

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