Protective Effect of Rho-Associated Protein Kinase (ROCK) Activated by Bone Marrow Mesenchymal Stem Cells on Bone Strength and Osteoblasts in Rats with Osteoporosis

This study assesses BMSCs’ effect on bone strength and osteoblast activity in rats with osteoporosis. 40 SD female rats were assigned into normal (A) group, model (B) group, puerarin (C) group, and BMSCs (D) group followed by analysis of bone strength by small animal bone strength analyzer and the expression of ROCK1 protein in tibia by immunohistochemistry. The bone strength of group B was lower than group A ( P < 0.05), and higher in groups C and D than group B ( P < 0.05) with further higher in group D than group C ( P < 0.05). Group A showed obvious mesh cancellous bone trabecular bone and continuity, compact structure, and group B cells appeared loose and irregular distribution, parts cancellous bone trabeculae decrease and part of the fracture, and arranged in sparse irregular distribution. The decrease of trabecular bone in group C and D is not more obvious than group B and the morphology in group D got better improved than in group C. Group B showed lower proliferation of osteoblasts and ALP activity than group A ( P < 0.05) and the proliferation and ALP activity in groups C and D was increased significantly compared with group B ( P < 0.05). ROCK1 expression was significantly lower in group B than group A ( P < 0.05) higher in groups C and D than group B ( P < 0.05). Bone marrow mesenchymal stem cells (BMSCs) can effectively increase the bone strength and activity of osteoblasts in rats with osteoporosis, and promote the activation of ROCK signal.