| Objective To investigate the therapeutic effect of EPCs transplantation on ovariectomized osteoporotic rats. Methods Sixty female non-pregnant Wistar rats were randomly divided into sham operation group, model group and EPCs group, with 20 rats in each group. One week after operation, tail vein injection was given for 7 days. The weight of rats was measured regularly. At 13 weeks, serum 25-hydrozyvitamin D [25(OH)D], bone alkaline phosphatase (BAP), type I collagen C-terminal peptide (CTX-I) and tartrate-resistant acid phosphatase 5b (TRAP 5b) were detected by ELISA. The expression of TGF-beta/Smads in vertebral body was detected by RT-PCR and Western Blot. Further assessments included bone mineral density, bone calcium content and biomechanical properties, and pathological changes were observed by HE staining. Results 8 weeks after modeling, the weight of the model group was significantly higher than that of the sham operation group (P<0.05). The weight of the EPCs group was significantly lower than that of the model group (P<0.05). Bone mineral density and bone calcium content in the model group were significantly lower than those in the sham operation group (P<0.05). Bone mineral density and bone calcium content in the EPCs group were significantly higher than those in the model group (P<0.05). Compared with the sham operation group, the serum levels of 25(OH)D and BAP in the model group were decreased, and the levels of CTX-I and TRAP5b were increased (P<0.05). Compared with the model group, serum levels of 25(OH)D and BAP increased, and levels of CTX-I and TRAP 5b decreased in the EPCs group (P<0.05). Biomechanical tests showed that the ultimate load, ultimate stress and elastic modulus of the model group were significantly lower than those of the sham operation group (P<0.05). The ultimate load and elastic modulus of the EPCs group were significantly higher than the model group (P<0.05). HE staining showed a reduction in osteoporosis in rats after EPCs transplantation. Compared with the model group, the expression of TGF-β1, Smad2 and Smad3 in EPCs group was significantly increased (P<0.05). Conclusion EPCs transplantation may play a role in the treatment of osteoporosis in ovariectomized rats by regulating the TGF-β / Smads pathway. |