Capsaicin Activates Transient Receptor Potential Vanilloid Subtype 1 (TRPV1) of Rat Bone Marrow-derived Stromal Cells (BMSCs) in vitro

Abstract

We studied rat femur bone marrow stromal cells (BMSCs) and microenvironment turnover in capsaicin (CAP)-conditioned media in vitro. Proliferation, differentiation and TRPV1 expression at the mRNA level (RT-PCR) of conditioned BMSCs, and pH changes and calcium assay of the conditioned culture media were examined; the obtained data were statistically analyzed. Elapsed time-dependent cell proliferation of BMSCs peaking at day 10 was observed in alkaline phase and 37°C microenvironment. Although there were no significant differences of proliferation in different conditions on designated experimental days, day 10 was the turning point of proliferation phase where intermittent administration of 25 µM CAP resulted in the least amount of cell proliferation than other culture conditions on day 14. The present RT-PCR study revealed expression of TRPV1 mRNA during 3 to 4 days (either day 3 or day 7) after single or intermittent exposure under 25 µM CAP. This study elucidated that by intermittent addition of 25 µM CAP into the culture medium, the CAP-sensing TRPV1 of the rat BMSCs was activated to significantly mediate Ca²⁺ influx leading to cell death, and the TRPV1 was desensitized between day 7 and day 10 in vitro.