Objective      To observe the effects of transient receptor potential (TRP) channels on stretch-induced injury of human brain microvascular endothelial cells (HBMECs) and to explore its mechanism of signaling pathway.       Methods      After mechanical stretch by a mini-type multi-functional bio-impact machine

HBMECs were divided into a control group

a stretch group

a stretch+SKF-96365 group

a stretch+low-molecular-weight heparin (LMWH) group and a stretch+N-nitro-l-arginine methyl ester (L-NAME) group. The concentrations of free calcium ion in the cells before and after mechanical stretch were observed by confocal laser scanning microscopy and determined by flow cytometry. The expression of endothelial nitric oxide synthase (eNOS) protein was detected by Western blotting.       Results      The concentration of free calcium ion detected by flow cytometry increased in the stretch group and stretch+LMWH group (P0.05)

and decreased in the stretch+SKF-96365 group (P0.05). The expression of eNOS protein detected by Western blotting increased in the stretch group (P0.05) and decreased in the stretch+SKF-96365 group and stretch+L-NAME group (P0.05).       Conclusion      The activation of TRP channels in HBMECs induced by mechanical stretch increases the free calcium concentration and the expression of eNOS protein. The mechanism may involve the influx of extracellular calcium ions.