MAPK信号通路在镉致大鼠肝细胞凋亡中的作用

The role of the MAPK signaling pathways in the apoptosis of rat hepatocytes induced by cadmium

探讨MAPK通路在镉诱导大鼠肝细胞凋亡中的作用。采用两步灌流法获得大鼠肝细胞,经过24h培养,用醋酸镉、醋酸镉与MAPK抑制剂(p38抑制剂SB202190、JNK抑制剂SP600125、ERK抑制剂U0126)共同处理肝细胞。用MTT法检测细胞存活率,倒置显微镜和荧光显微镜观察细胞形态和凋亡,免疫组织化学法检测p38蛋白表达。结果表明,镉可极显著提高肝细胞磷酸化p38的表达量(P<0.01),而SB202190能极显著降低其表达(P<0.01)。SB202190可以显著或极显著提高镉处理组细胞的存活率(P<0.05或P<0.01),减少变形细胞和凋亡细胞数量,但SP600125和U0126作用相反。说明镉暴露导致肝细胞p38MAPK途径激活而引起细胞凋亡。

To investigate the effect of mitogenactivated protein kinase（MAPK） on the apoptosis of rat hepatocytes induced by cadmium. Rat hepatocytes were isolated by a twostep perfusion tech nique. After 24 h planting,hepatocytes were treated with cadmium in the presence or absence of MAPK signaling inhibitors （p38 MAPK inhibitor SB202190,JNK inhibitor SP600125,ERK inhibi tor U0126）. Cell viability was evaluated with a colorimetric using MTT level. Cell morphology and apoptosis were photographed under inverted and fluorescence microscope. Immunohistochemistry analysis was performed to recognize the activated phosphorylated forms of p38 MAPK kinases in Cd treated hepatocytes in the presence or absence SB202190 and NAC. The results showed that the phosphorylation of p38 MAPK increased after Cd treatment and the activations were inhibited by the treatment with its inhibitor SB202190. SB202190 reversed significantly Cdinduced cell death. SB202190 effectively inhibited Cdinduced alterations in the morphology and apoptosis of hepato cytes. While SP600125 and U0126 increased Cdinduced cell death significantly. The findings sug gested that Cd induced rat hepatocytes apoptosis through p38 MAPK pathway.