| Objective To investigate the effect of triptolide(TP) on osteoclast differentiation in emasculated mice with osteoporosis and its possible molecular mechanism.Methods To establish osteoporosis model of ovariectomized mice, they were divided into Sham group, OVX group, TP group and Livial group. The corresponding drug treatment was given on the 3rd day after modeling. Six weeks after treatment, TRAP staining was used to detect the number of osteoclasts in the left femoral metaphysis. Three dimensional images of bone structure were reconstructed by Micro-CT to detect the bone mineral density (BMD), trabecular number (Tb.N), bone volume fraction (BV/TV), bone surface area tissue volume ratio (BS/TV), trabecular separation (Tb.Sp). ELISA was used to detect the content of IL-6, TNF-α, bone formation marker osteocalcin (OC), bone resorption marker tartrate resistant acid phosphatase(TRAcp5b) in peripheral blood. Western Blot (WB) was used to detect the protein expression content of p65, p-p65, IκBα, p-IκBα.Results The number of osteoclasts around the trabecular bone: Compared with the Sham group, number in the OVX group significantly increased; number in the TP group significantly decreased compared with the OVX group; while there was no significant difference between TP group and Livial group. Analysis of bone parameter: Compared with Sham group, BMD, Tb.N, BV/TV and BS/TV in OVX group significantly decreased (P<0.01), while Tb.Sp significantly increased (P<0.01); compared with OVX group, BMD, Tb.N, BV/TV and BS/TV in TP and Livial groups significantly increased (P<0.01), while Tb.Sp significantly decreased (P<0.01); there was no significant difference between TP group and Livial group in those bone parameter. The content of IL-6, TNF-α, OC, TRAcp5b: The serum levels of inflammatory factors IL-6 and TNF-α in OVX group were significantly higher than those in Sham group (P<0.01), and the level of bone resorption marker TRAcp5b increased (P<0.01), while that in the TP group was significantly lower than that in the OVX group (P<0.01). The level of bone formation marker OC was not significantly different from Sham group. The protein expression: Compared with Sham group, the expression levels of p65 and IκBα in OVX group were unchanged, while the expression levels of p-p65 and p-IκBα significantly increased (P<0.01); after TP treatment, the expression levels of p65 and IκBα remained unchanged, but the expression levels of p-p65 and p-IκBα significantly decreased (P<0.01); there was no significant difference between TP group and Livial group in the expression levels of p65, IκBα, p-p65 and p-IκBα (P>0.05).Conclusion TP inhibits osteoclast differentiation and improves bone loss in emasculated mice. The molecular mechanism may be related to inhibiting the expression of inflammatory factors IL-6 and TNF-α and the phosphorylation level of NF-κB signaling pathway. |
