| Objective To observe the protective effect of visceral adipose tissue derived serine protease inhibitor (vaspin) on osteoporosis in ovariectomized rats, and to explore the potential mechanism. Methods Thirty female SD rats were randomly divided into sham group (Sham), OVX group (OVX), and OVX+vaspin group, with 10 rats in each group. Rats in OVX group and OVX+vaspin group were performed ovariectomy to construct postmenopausal osteoporosis model. Rats in OVX+vaspin group received intraperitoneal injection of 1μg/kg vaspin every day, while rats in Sham and OVX groups received intraperitoneal injection of the same amount of normal saline. After 12 weeks of intervention, serum concentrations of type 1 collagen pron-terminal propeptide (P1NP), osteocalcin (OCN), tartrate-resistant acid phosphatase (TRAP), type 1 collagen C-terminal peptide (CTX), interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α) were detected. Then histological examination, biomechanical analysis, and micro-CT examination were performed to evaluate bone microstructure and bone strength. The effects of vaspin on mRNA and protein expressions of OPG and RANKL in the bone tissue were detected using qRT-PCR and Western blotting. Results After 12 weeks of vaspin intervention, compared those in OVX group, serum P1NP and OCN in OVX+vaspin group increased significantly, while serum TRAP, CTX, IL-1β, and TNF-α decreased significantly (P<0.05). The mRNA and protein expression levels of OPG and RANKL in the bone tissue of the OVX group were respectively up-regulated and down-regulated compared to those in OVX group. Conclusion Vaspin may regulate bone metabolism in OVX rats by up-regulating the expression of OPG and down-regulating the expression of RANKL, improving bone microstructure and bone strength, and thus play an anti-osteoporosis role. |