[Study on the effect of curculigoside on osteoporosis]

Objective: To investigate the regulation of curculigoside on osteogenic differentiation of MG63 and the protective effect on osteoporosis model mice. Methods: The effects of curculigoside on the survival rate of dexamethasone or H(2)O(2) treated MG63 were detected by methyl thiazolyl tetrazolium (MTT). The specimens were divided into six groups: blank control group, blank administration group, model group (dexamethasone or H(2)O(2) treatment group), low dose group (dexamethasone or H(2)O(2)+1.0 μmol/L curculigoside), medium dose group (dexamethasone or H(2)O(2)+2.5 μmol/L curculigoside) and high dose group (dexamethasone or H(2)O(2)+5.0 μmol/L curculigoside), the sample size of each group was 10. Western blotting was used to detect the expression of osteogenic differentiation-related proteins [type Ⅰ collagen, integrin β1, osteoblast-specific transcription factor (Osterix), osteocalcin and osteopontin] in MG63 cells after 1, 7 and 14 days incubated with 0, 1.0, 2.5 and 5.0 μmol/L of curculigoside. The sample size for each group at each time point was six. The experimental mice were divided into 4 groups: blank group, model group (dexamethasone treatment group), curculigoside low-dose group (dexamethasone+5 mg/kg curculigoside) and high-dose group (dexamethasone+45 mg/kg curculigoside), twenty each. After treatment, the tibia of the mice in each group were subjected to sacral HE staining. The number of osteoclasts was counted, and the levels of oxidative related factors in serum were determined by enzyme-linked immunosorbent assay (ELISA). Results: The MTT results showed that compared with the blank control group [(100±3.7)%], the cell survival rate decreased to (44.1±5.7)% after treatment with dexamethasone, and the survival rate increased to (79.7±3.8)% after treatment with 5.0 μmol/L of curculigoside. The cell survival rate decreased to (59.1±4.7)% after H(2)O(2) treatment, and the survival rate increased to (80.8±3.5)% after treatment with 2.5 μmol/L of curculigoside. The results of Western blotting showed that the expression of type Ⅰ collagen and integrin β1 in MG63 cells was significantly increased after 1.0, 2.5 and 5.0 μmol/L of curculigoside for 1, 7 and 14 days compared with 0 μmol/L of curculigo side for the same period. After increasing (P<0.05), the expression of Osterix and osteocalcin was significantly increased after 1 day of incubation (P<0.05). However, compared with 0 μmol/L curculigoside treatment, the expression of osteopontin in MG63 cells was not significantly different after incubation with 1.0, 2.5, 5.0 μmol/L of curculigoside for 7 and 14 days (P>0.05). Compared with the blank group, the number of tibia osteoclasts in the osteoporosis model group increased. In the low-dose and high-dose groups of curculigoside, the tibia cortex was more continuous and the number of osteoclasts decreased. Compared with the blank group, the activity of oxygen in the osteoporosis model group was significantly increased (P<0.05), and superoxide dimutase and catalase were significantly decreased (P<0.05). Conclusions: Curculigoside promotes the differentiation of MG63 cells by increasing the expression of osteoblast differentiation-related proteins, and has a certain therapeutic effect on dexamethasone-induced osteoporosis mice.