烧伤小鼠早期肝组织JNK1、AP-1的活性变化

Changes of the activity of hepatic JNK1 and AP-1 during the early stage in burned mice

目的 :观察烧伤小鼠早期肝组织JNK1磷酸化及核转位、AP - 1DNA结合活性时相变化特点 ,初步探讨创伤应激早期糖皮质激素抵抗的分子机制。方法 :将 36只BALB/C小鼠随机分为正常对照组和实验组 ,实验组给予背部Ⅲ度 15 %～ 2 0 %烧伤。分别于伤后 2h、 4h、 6h、 12h、 2 4h用westernblot测定肝组织JNK1磷酸化及核转位 ,用EMSAs测定AP - 1的DNA结合活性。结果 :烧伤后 2hJNK1磷酸化程度和核内JNK1的含量显著增加 ,4h达到高峰 ,6h时仍显著高于正常对对照组水平 ,以后逐渐恢复正常。烧伤后 2hAP - 1的DNA结合活性与正常对照组相比无显著差异 ,4h后AP - 1的DNA结合能力逐渐升高 ,12h达到最大值 ,以后逐渐恢复 ,至 2 4h仍显著高于正常对照组。结论 :烧伤早期不仅引起小鼠肝组织JNK1的磷酸化程度显著增强 ,由胞浆向胞核的转位显著增加 ,而且引起AP - 1的DNA结合活性显著增强。揭示创伤应激早期糖皮质激素抵抗可能与JNK1、AP - 1活性增加有关。

Objective:To observe the changes of the activity of hepatic JNK1 and AP-1during the early stage in burned mice.Methods:Thirty-six BALB/C mice were randomly divided into control group and experiment group.The mice in experiment group were given 15-20% thickness third degree burn in the back.JNK1 Phosphorylation status and its transfer from cytoplasm to nucleys were respectively detected by western blot 2,4,6,12,and 24 hours after burn and electrophoretic mobility shift assays(EMSA)were employed to examine the AP-1 DNA binding capacity in liver.Results:Two hours after burn,the Phosphorylation status of JNK1 and the levels of JNK1 in nucleus were obviously increased,peaked at 4 hours and gradually returned to normal after 6 hours.There was no significant difference of the AP-1 DNA binding capacity between two groups 2 hours after burn but that in experiment group markedly elevated at 4 hours,peaked at 12 hours and gradually returned to normal.However,it was still obviously higher than that in control group 24 hours after burn.Conclusion:The JNK1 Phosphorylation,transfer of JNK1 from cytoplasm to nucleus and the AP-1 DNA binding capacity are significantly up-regulated in liver in burned mice,which indicates that glucocorticoid resistance after severe trauma may be associated with the elevation of JNK1 and AP-1 activity in the early stage.