The effect of the Ginkgo biloba extract in the expression of Bax, Bcl-2 and bone mineral content of Wistar rats with glucocorticoid-induced osteoporosis.

Objective: Evaluate the effects of the extract of Ginkgo biloba (EGb) in the glucocorticoid-induced-osteoporosis through the Bax and Bcl-2 expressions by osteoblast cells, the x-ray and bone density of the tibia.

Method: Rats were divided into five groups: osteoporosis; EGb1 (28 mg/kg); EGb2 (56 mg/kg); alendronate (0.2 mg/animal) and control. The treatments were conducted for 20 (n = 30) and 30 days (n = 30). The Bax and Bcl-2 expressions were evaluated in osteoblasts of the mandibular alveolar bone. The tibias were radiographed to evaluate the X-ray and bone density. The control group was compared with the osteoporosis' (Student's t-test/Mann-Whitney). The other groups were analyzed by analysis of variance test followed by Dunnett/Dunnett T3 (p < 0.05).

Results: When compared the osteoporosis to the control group (p <0.05): Bax and x-ray density increased; Bcl-2 and the bone density reduced. When compared with the osteoporosis group (p < 0.05), alendronate (30 days), EGb1 and EGb2 (20/30 days) increased the Bcl-2 expression; EGb2 and alendronate (20 days) EGb1 and EGb2 (30 days) reduced the Bax expression; and EGb1 and EGb2 (20/30 days) reduced the X-ray density.

Conclusions: The EGb improved the Bcl-2 and reduced the Bax expression by osteoblasts in the mandibular alveolar bone and recovered the mineral content in the tibia of rats with glucocorticoid-induced-osteoporosis.