THE OSTEOPROTECTIVE EFFECT OF Azadirachta excelsa LEAVES EXTRACT ON BONE OF STREPTOZOTOCIN-INDUCED DIABETIC RATS

Insulin signalling in bone favours whole-body glucose homeostasis by activating osteocalcin, which is important for bone remodeling. However, diabetes causes deficient production of insulin which consequently affects the osteocalcin and bone turnover marker. The aim of this study was to explore the potential of A. excelsa to improve insulin and osteocalcin secretion, resulting in improved bone histomorphometric and bone turnover marker in STZ- induced diabetic rats. The experimental rats were divided into normal control (NC), diabetic control (DC), Metformin-treated diabetic (DMET) (positive control) and A. excelsa -treated diabetic (DAE) rats with the treatment period of eight weeks. After the treatment, the femoral bones were removed and bone morphometrical parameters  were defined using Micro-CT scan. The bones were analysed for mineral density (BMD) and trabecular parameters. The bones samples were decalcified for histological preparation and  images of the  was hematoxylin and eosin (H&E) stained bones were captured and analysed. The concentrations of serum insulin, osteocalcin and bone turnover marker were evaluated using specific ELISA kits. The study showed that A. excelsa caused a significant increase in insulin and osteocalcin levels. A. excelsa also represents ameliorative effects on trabecular bone of the diabetic rat. The data also demonstrated that with A. excelsa treatment, it moderately restored the balance between bone formation and bone resorption markers. These data confirmed that A. excelsa extract could attenuate the STZ-induced bone loss and reverses the deterioration of bone microarchitecture in diabetic rats. This finding indicates the osteoprotective effects presence in the A. excelsa extract.