Ethanolic and water rhizome extracts of Ligusticum chuanxiong Hort alleviate hypoxia/reoxygenation-injured H9c2 cardiomyoblasts through up-regulated ERK1/2 and Bcl-2 expression

Abstract

Ligusticum chuanxiong Hort (LC) is used in traditional medicine throughout Southeast Asia as a cardiovascular protective herb, antioxidant, vasorelaxant, and anti-inflammatory. To demonstrate the protective mechanisms of LC on hypoxia/reoxygenation (HR) induced injury in H9c2 cardiomyoblasts, intracellular reactive oxygen species (ROS) content was measured using dichlorodihydrofluorescein diacetate. The cardioprotective effects of LC ethanolic (E) and water (W) extracts were measured by the MTT assay. Changes in cell and nuclear morphology were observed under a phase-contrast and a fluorescent microscope. The mitochondrial membrane potential (MMP) was detected by Rhodamine123 staining. The expressions of pERK1/2, ERK1/2, and Bcl-2 were determined by immunoblotting. LCE and LCW extracts caused no cytotoxicity or ROS generation to H9c2 cardiomyoblasts. The incubation of LCE or LCW during hypoxia increased cell survival (p < 0.05) compared to HR without the extracts. HR-induced cells demonstrated cellular atrophy, cell membrane shrinkage, and DNA condensation. Healthy cells were found in the control, LCE and LCW-treated HR-induced cells. LC restored the reduction of MMP, while LCE and LCW increased the pERK/ERK ratio (p < 0.001). Meanwhile, LCW increased Bcl-2 expression (p < 0.05). LC extracts effectively protected H9c2 cardiomyoblasts from injury caused by HR exposure, suggesting a beneficial use of LC in alleviating damaged cardiomyoblasts from acute ischemia.