Mitigative Effect of Sipjeondaebo-tang on RhoA Activation in Cold-Exposed Vascular Cells

Abstract

Objective To investigate the vasodilatory effect of Sipjeondaebo-tang by inhibiting RhoA activity in vascular cells during cold exposure. Methods Human vascular endothelial cells and pericytes were pretreated with Sipjeondaebo-tang for 30 min, followed by incubation at 37 °C (control) or 25 °C (cold exposure) for 30 min. Activation of endothelin-1-mediated RhoA in pericytes was assessed by pretreating the cells with Sipjeondaebo-tang for 30 min, followed by incubation with endothelin-1 at 37 °C for 30 min. Western blotting was performed to measure the expression of active RhoA. Endothelin-1 and nitric oxide release from endothelial cells was examined with enzyme-linked immunosorbent assay kits. The formation of stress fibers and focal adhesion complexes was analyzed by immunocytochemistry. Results Cold treatment activated RhoA in both pericytes and vascular endothelial cells, whereas Sipjeondaebo-tang treatment inhibited this activation. Sipjeondaebo-tang treatment also reversed the cold-mediated production of endothelin-1 and nitric oxide. Cold exposure promoted the formation of stress fibers and focal adhesion complexes by increasing the expression of phospho-focal adhesion complex kinase, whereas Sipjeondaebo-tang treatment suppressed this response. Conclusions These findings suggested that Sipjeondaebo-tang inhibits cold-induced RhoA activation and its related pathway components, including endothelin-1 and nitric oxide, in vascular cells. Therefore, Sipjeondaebo-tang could be beneficial for the treatment of Raynaud’s phenomenon. Keywords: Raynaud’s phenomenon, cold, rhoA, endothelin-1, nitric oxide, Sipjeondaebo-tang