P38MAPK Signal Pathway Modulated Proliferation, Apoptosis And Cell Cycle Of Rat Hepatic Stellate Cells Stimulated By Acetaldehyde

Background and aimsLiver fibrosis was the necessary stage in the evolution from chronic liver disease to cirrhosis, and was the reversible aggradation of ECM (extracellular matrix) during wound healing after liver cell injury. It's showed that the activation of hepatic stellate cell (HSC) was the key element in the progress of hepatic fibrosis, and the acetaldehyde was the key factor in alcoholic hepatic fibrosis, it played a basilic role in the regulation of HSC activation, proliferation, and ECM secretion. In recent years,some studies had approved that mitogen-activated protein kinase(MAPK) including ERK,JNK and P38 was one of the main signal pathway in the activation and proliferation of HSC. The previous research has approved ERK (extracellular signal-regulated kinase) and c-JNK(c-jun N-terminal kinase) signaling pathway play important role in proliferation of HSC stimulated by acetaldehyde, however, there are few research about the molecular mechanism which P38 regulates HSC proliferation and apoptosis.This experiment was to investigate the effects of blocking p38MAPK by it's specific blocker, SB203580, on the proliferation, apoptosis and cell cycle of rat hepatic stellate cell(HSC).MethodsRat HSCs stimulated by acetaldehyde(200μmol/L) were incubated with SB203580 at concentrations of 5, 10 and 20μmol/L respectively. Cellular proliferation inhibition rate (CPIR) were analyzed by MTT assay, and the changes of apoptosis rate and cell cycle were analyzed by flow cytometry, and the variability of P38 was examined by Western Blot.ResultsAcetaldehyde increased obviously HSC proliferation and P38 activity, and the expression of P-P38 decreased relatively by SB203580 (P﹤0.05), compared with acetaldehyde control group, SB203580 at different concentrations inhibited the proliferation of HSC significantly and CPIR was 21.6%, 27.0%, and 31.5% respectively (P﹤0.05). SB203580 also promoted the apoptosis of HSC significantly with the apoptotic rate of (13.7±0.3 ) %, (14.9±0.2)%, and (16.1±0.2)% respectively(P﹤0.05). And the cell percentage of G1/G0 was significantly increased by (29.1±1.9)%,(35.5±3.4)%,and (46.0±2.6)% respectively (P﹤0.05), while, cell percentage of S was significantly decreased by(53.4±2.6)%,(48.4±3.6)%,and (43.8±1.1)%(P﹤0.05).ConclusionAfter P38MAPK was blocked by SB203580 specifically in HSC stimulated by acetaldehyde, the activity of P38 was suppressed, cell proliferation is inhibited but apoptosis promoted , and the cell cycle from G₁ to S was arrest.