HMC05 attenuates vascular contraction through inhibition of RhoA/Rho-kinase signaling pathway

Aim of the studyHMC05, an extract from eight different herbal mixtures, has been developed to treat cardiovascular disease. This extract has a vasorelaxant and anti-atherosclerotic action. We hypothesized that HMC05 attenuates vascular contraction through inhibition of the RhoA/Rho-kinase signaling pathway.Materials and methodsRat aortic ring preparations were mounted in organ baths and subjected to contraction and relaxation. Phosphorylation of 20 kDa myosin light chains (MLC20) and myosin phosphatase targeting subunit 1 (MYPT1) were examined by immunoblot. We also measured the amount of GTP RhoA as a marker for RhoA activation.ResultsIn endothelium-denuded aortic ring preparations, HMC05 relaxed vascular contraction induced by 6.0 mM NaF, 100 nM phenylephrine, 30 nM thromboxane A2 agonist U46619 or 1.0 μM protein kinase C (PKC) activator phorbol-12,13-dibutyrate (PDBu) in a decreasing order. HMC05 relaxed aortic ring preparations precontracted with sodium fluoride (NaF) whether endothelium was intact or denuded. Pre-incubation with HMC05 for 30 min dose-dependently inhibited the NaF-induced contractile response. In vascular strips, HMC05 decreased the phosphorylation level of both MLC20 and MYPT1Thr855 induced by 6.0 mM NaF. Furthermore, HMC05 decreased the amount of GTP RhoA activated by NaF.ConclusionsHMC05 attenuates vascular contraction through inhibition of the RhoA/Rho-kinase signaling pathway. HMC05 may be useful for the treatment and/or prevention of cardiovascular diseases associated with activation of RhoA/Rho-kinase signaling pathway.

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