Effect of genistein on bone microstructure in femoral head of diabetic rats

Abstract

Objective To assess the osteoporotic changes in diabetic rats and protective effects of genistein. Methods A total of 60 adult SD rats (four months old and weighted (200±20) g) were divided into three groups according to the random number table: normal control group(group CON), diabetic group (Group DM) and intervention group (Group Gen) (20 rats in each group). Rats in Group DM and Group Gen were injected with streptozotocin(STZ) at 60 mg/kg in the left lower abdominal cavity to establish STZ-induced diabetic model, which was considered valid if blood glucose was greater than or equal to 167 mmol/L after 72 hours. Group Gen received 30 mg·kg-1·d-1 of genistein, once a day. An equal volume of citrate buffer was given to Group CON, both were administered intraperitoneally. The immunohistochemical evaluation of the femoral head subchondral region and FⅧ factor were conducted in each group after 15 weeks. The microvessel density was measured with the ink perfusion. Vascular endothelial growth factor(VEGF) mRNA expression was measured and analyzed by the in situ hybridization. The date analysis was performed using LSD test. Results (1) The trabecular bone in Group CON was thick and had complete osteoblasts area. The trabecular bone in Group DM was sparse and thin, the nucleus was pyknotic. The trabecular bone in Group Gen had arranged more closely. (2) Compared with the Group CON, the number of osteoblast (13.2±1.3 vs 22.4±2.5) decreased, microvascular relative area ((8.7±0.7)% vs (4.7±0.6)%) increased, FⅧ factor gray value of expression (137±5 vs 164±5) and the expression of VEGF mRNA (186±5 vs 213±4) decreased in Group DM. (3) Compared with Group DM; osteoporosis and pathological alterations of micrangium were improved in Group Gen. Osteoblasts (19.20±1.9) increased, microvascular unit area ((5.6±0.5)%) decreased, gray value of FⅧ factor (159±7)and the expression of VEGF mRNA (200±2)increased in Group Gen. Differences among these groups were statistically significant (F=39.191-58.815, respectively, all P<0.01). Conclusion Osteoporoic changes occur in the early stage of diabetes, and genistein has a protective effect on the microstructure. Key words: Diabetes mellitus; Genistein; Femur head; Microvessels; In situ hybridization