胞外信号调节激酶信号通路在血管钠肽 减轻大鼠肝缺血再灌注损伤中的作用

Objective To investigate the protective role of extracellular signal-regulated kinase (ERK) signaling pathway in the process that vasonatrin peptide (VNP) reduces hepatic ischemia-reperfusion injury in rats. Methods Twenty SD rats, weighting 200-250 g, were randomly divided into four groups and each group has five rats. The four groups were sham operation group (S group), ischemia-reperfusion group (I/R group), VNP group (V group) and PD98059+ VNP group (P+ V group). In the rat model of hepatic warm ischemia and reperfusion, the hepatic artery and portal vein of the left lobe and middle lobe of the liver were clamped with arterial clamp for 45 min followed by reperfusion for 120 min. In the V group, VNP (50 μg/kg) was injected 10 minutes before ischemia. In the P+ V group, PD98059 (2 mg/kg) was injected 20 min before VNP injection followed by VNP administration and I/R treatment. The serum levels of alanine amino transaminase (ALT), aspartate amino transferase (AST), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and the superoxide dismutase (SOD) in liver tissue homogenate and malondialdehyde (MDA) were measured. The histopathology of liver tissue was observed. The contents of p-ERK1/2 were detected by Western blot. Results Compared with S group, in I/R group and P+ V group the serum levels of ALT [(489.65±11.22), (333.05±24.77) vs. (33.78±4.88) U/L], AST [(651.43±14.99), (503.18±21.48) vs. (154.84±12.32) U/L], TNF-α [(12.83±1.09), (9.64±0.57) vs. (2.11±0.11) ng/L], IL-1β [(7.19±0.62), (5.12±0.22) vs. (1.10±0.49) ng/L], MDA [(8.00±0.88), (5.60±1.01) vs. (2.76±1.29) μmol/mg] increased, while SOD [(54.89±10.60), (68.85±8.33) vs. (126.10±15.63) nmol/mg]decreased (allP<0.05). The histopathology of liver tissue revealed that liver structure damaged more seriously in I/R group and P+ V group. Western blot analysis showed that p-ERK1/2 decreased significantly in I/R group and P+ V group. Compared with I/R group, ALT, AST, MDA, TNF-α and IL-1β decreased significantly and SOD increased significantly in V group (allP<0.05). The histopathology of liver tissue revealed that liver structure was damaged slightly, and p-ERK1/2 increased significantly in V group compared with I/R group (P<0.05). Conclusion VNP can significantly reduce hepatic ischemia-reperfusion injury through activation of p-ERK1/2 signaling pathway and inhibition of hepatocyte inflammatory response.