ABSTRACT
Background: Hypothyroidism is associated with dysfunction of the bone turnover with reduced osteoblastic bone formation and osteoclastic bone resorption. Mesenchymal stem cells [MSCs] secrete various factors and cytokines that may stimulate bone regeneration. The aim of this study was to determine the effects of MSCs-conditioned medium [CM] in hypothyroidism male rats after inducing bone defect
Methods: In this study, 24 male rats were randomly assigned to three groups: [I] hypothyroidism + bone defect [HYPO], [II] hypothyroidism + bone defect + CM [HYPO + CM], and [III] no hypothyroidism + bone defect [control]. Four weeks after surgery, the right tibia was removed, and immediately, biomechanical and histological examinations were performed
Results: The results showed a significant reduction in bending stiffness [32.64 +/- 3.99], maximum force [14.63 +/- 1.89], high stress load [7.59 +/- 2.31], and energy absorption [12.68 +/- 2.12] at the osteotomy site in hypothyroidism rats in comparison to the control and hypothyroidism + condition medium groups [p < 0.05]. There was also a significant decrease in the trabecular bone volume [3.86 +/- 3.88] and the number of osteocytes [5800 +/- 859.8] at the osteotomy site in hypothyroidism rats compared to the control and hypothyroidism + condition medium groups [p < 0.01 and p < 0.02, respectively]
Conclusion: The present study suggests that the use of the CM can improve the fracture regeneration and accelerates bone healing at the osteotomy site in hypothyroidism rats