Hirudin promotes proliferation and osteogenic differentiation of HBMSCs via activation of cyclic guanosine monophosphate (cGMP)/protein kinase-G (PKG) signaling pathway

Osteoporosis is a public health problem resulting in higher susceptibility to bone fracture. Hirudin is known as a direct thrombin inhibitor, which is isolated from the salivary gland of the medicinal leech. The present study aimed to evaluate the effect of Hirudin on the proliferation and osteogenic differentiation of human bone marrow-derived mesenchymal stem cells (HBMSCs). In our study, the effect of Hirudin on the proliferation of HBMSCs was evaluated with the CCK-8 and MTT assays. The capacity of osteogenic differentiation and mineralization of HBMSCs was evaluated with ALP and alizarin red staining, respectively. cGMP content was determined by ELISA. Western blotting and qRT-PCR were used to investigate the effect of Hirudin on the expression of osteoblast-specific markers, including Runx2, osterix (OSX), osteocalcin (OCN), and collagen1 (Col1). In our study, Hirudin treatment promoted cell viability. Moreover, Hirudin treatment increased ALP activity of HBMSCs and red coloration of alizarin. Interestingly, cGMP inhibitor partly reversed the effect of Hirudin on the proliferation, differentiation and mineralization of HBMSCs. In conclusion, Hirudin promoted the proliferation, differentiation and mineralization of HBMSCs via activation of cGMP signaling pathway. Hence, Hirudin contributed to bone remodeling and might represent as an effective agent for the treatment of osteoporosis.