细菌内毒素对枯否细胞丝裂原活化蛋白激酶家族的影响

为阐明LPS诱导全身炎症反应失控的信号转导机制，采用Western blot检测LPS刺激对枯否细胞ERK、JNK、p38MAPK蛋白表达及磷酸化水平的影响。结果显示，LPS刺激后，枯否细胞内ERK、JNK、p38MAPK蛋白表达无明显变化，但其磷酸化水平均发生了显著变化，刺激后5min即明显升高，并分别于30、45、20min达到高峰，然后逐渐下降，2h后基本恢复至正常水平，其中以p38MAPK变化最快且变化幅度最大。LPS浓度在10pg/ml-100ng/ml范围内时，ERK、JNK、p38MAPK的磷酸化水平与LPS刺激浓度呈明显的剂量依赖性。提示ERK、JNK、p38MAPK均是LPS信号转导途径中的重要信号分子，其中p38MAPK在LPS所介导的枯否细胞早期反应中可能较ERK和JNK有着更为重要的作用。

PROTEIN EXPRESSION AND PHOSPHORYLATION OF MITOGEN-ACTIVATED PROTEIN KINASES IN MURINE KUPFFER CELLS INDUCED BY LIPOPOLYSACCHARIDE(LPS)

To elucidate the signal transduction mechanism of systemic inflammatory response syndrome induced by LPS,Western blot analysis was used to assay the protein expression and phosphorylation levels of ERK, JNK,and p38 MAPK in murine KC which were stimulated by LPS. It was found that LPS treatment resulted in no significant change in their protein expression, but a rapid transient increase in their phosphorylation levels, which peaked at 30, 45,and 20 minutes,respectively; The values returned to mear baseline within 2 hours. Kinase phosphorylation levels of these three MAPKs induced by LPS were found to be dose dependent in a range of 10 pg/ml to 100ng/ml. No phosphorylation was observed in unstimulated cells. Among them, p38 MAPK shoned fastest and highest phosphorylation levels. The results show that LPS can markedly activate ERK, JNK,and p38 MAPK in KC, and p38 MAPK may play a more important role in LPS induced kupffer cell activation than ERR and JNK.