The systemic bone protective effects of Gushukang granules in ovariectomized mice by inhibiting osteoclastogenesis and stimulating osteoblastogenesis

Primary osteoporosis (POP), which is caused by unbalanced bone remodeling, leads to significant economic and societal burdens globally. Gushukang (GSK) granule serves as one commonly used prescription for POP in Traditional Chinese Medicine (TCM). The present study aimed to clarify the exact roles of GSK in bone remodeling with in vivo and in vitro assays. Here we showed that GSK prevented bone loss and the alternations of osteoporotic bone parameters as well as the decreased density of osteoclast in ovariectomized (OVX) mice. GSK inhibited receptor activator for nuclear factor-κ B Ligand (RANKL)-activated osteoclastogenesis in bone marrow macrophages (BMMs). At the molecular levels, GSK inhibited the expression of nuclear factor of activated T cells cytoplasm 1(NFATc1) and c-Fos, two master regulators of osteoclastogenesis. GSK also inhibited bone resorbed genetic expression of matrix metalloproteinase 9 (MMP9), cathepsin K (Ctsk), TRAP and carbonic anhydrase II (Car2). Meanwhile, GSK stimulated osteoblastogenesis from bone primary mesenchymal stem cells (MSCs) and enhanced the expression of Osteirx, and Runx2. GSK also stimulated the expression of Col-1, Osteocalcein and alkaline phosphatase (ALP). Our investigation established the systemic bone protective effects of GSK by suppressing osteoclastogenesis and stimulating osteoblastogenesis and laid bases for new drugs discovery in treating POP.