The influence of the sensory neurotransmitter calcitonin gene-related peptide on bone marrow mesenchymal stem cells from ovariectomized rats.

In order to explore the effects of calcitonin gene-related peptide (CGRP) on bone mesenchymal stem cells (BMSCs) from ovariectomized (OVX) rats, an OVX rat model was used. An ELISA was performed to examine the changes in CGRP level in the plasma and skeleton. The BMSCs from the sham rats were designated group A. The BMSCs from the OVX rats (groups B, C, D and E) were treated with different concentrations of CGRP (10-6, 10-8, 10-10 and 0 M) in vitro. The proliferation and osteogenic and adipogenic differentiation potential of the BMSCs were evaluated. BMSCs sheets and Bio-Oss® mixtures were transplanted into nude mice to observe the effects of CGRP on bone formation in vivo. The level of CGRP was decreased by almost 27 and 17 % in the plasma and bone, respectively, in OVX rats compared with sham rats (p < 0.05). Treatment with CGRP increased the proliferation and mineralization of BMSCs, and significantly decreased the lipid accumulation of BMSCs in a dose-dependent manner. The expression of Runx2 and Osterix was upregulated, but the expression of peroxisome proliferator-activated receptor γ was significantly downregulated in groups B, C and D compared with group E (p < 0.05). Micro computed tomography showed no difference between the images of the planted mixtures. Hematoxylin and eosin stain revealed the formation of slightly more hard bone-like structures in groups B and C. These results suggested that CGRP played a role in adjusting bone mass and strength by promoting the proliferation and osteogenic differentiation of BMSCs, as well as significantly suppressing the adipogenic differentiation of BMSCs.