Antiosteoporosis and bone protective effect of alpinumisoflavone in steroid-induced osteoporosis rats via alteration of apoptosis, inflammatory and RANK/RANKL/OPG signaling pathway

Objective: To estimate the bone protective effect of alpinumisoflavone, a natural prenylated isoflavonoid, against glucocorticoid-induced osteoporosis in rats. Methods: Male Wistar rats received intramuscular administration of dexamethasone (4 mg/mL) at a dose level of 7 mg/kg for 5 weeks, and then alpinumisoflavone (5, 10, and 15 mg/kg) and alendronate (2 mg/kg) from 2 weeks. The body weight and organ weight (femoral, vagina, and uterus) were estimated. MicroCT analysis, bone turnover markers, bone parameters, oxidative stress parameters, and inflammatory cytokines were estimated. mRNA expressions of related genes were also estimated. Results: Alpinumisoflavone remarkably boosted body weight and organ weight (ureters and vagina), improved microCT analysis parameters, and boosted levels of bone markers. Besides, alpinumisoflavone considerably (P<0.001) restored the level of bone turnover markers and oxidative stress parameters, remarkably suppressed the level of cytokines such as interleukin-1 beta, interleukin-6, tumor necrosis factor-alpha, and increased transforming growth factor-beta and insulin-like growth factor. It also significantly restored the osteoprotegerin (OPG, RANKL, and OPG/RANKL ratio) levels and the mRNA expression of Caspase (3, 6, 7, 9), BMPs, OPN, ALP, RUNX2, and OCN. Conclusions: The current result suggests the bone protective effect of alpinumisoflavone against glucocorticoid-induced osteoporosis in rats.