泛素-蛋白酶体途径对烫伤脓毒症大鼠肠道炎症反应与屏障功能的作用研究

Effect of ubiquitin-proteasome pathway on inflammatory reaction in intestine and its barrier function in rats with postburn sepsis

目的研究泛素蛋白酶体途径对烫伤脓毒症大鼠肠组织核转录因子κB(NFκB)活化、肿瘤坏死因子α(TNFα)表达以及血浆二胺氧化酶(DAO)活性的作用。方法采用30%总体表面积(TBSA)度烫伤合并内毒素攻击大鼠为模型模拟临床烫伤脓毒症。60只Wistar大鼠随机分为正常对照组、烫伤脓毒症模型组、泛素蛋白酶体抑制剂N乙酰亮氨酰亮氨酰正亮氨酸(ALLN)组、NFκB抑制剂吡咯烷二硫基甲酸酯(PDTC)组。采用凝胶电泳迁移率改变分析法(EMSA)分析肠组织NFκB活性;采用酶联免疫吸附法(ELISA)检测肠组织TNFα含量;采用分光光度法检测血浆DAO活性。结果各组肠组织NFκB活性于伤后1h均明显增强,并达到高峰(P均<0.01),之后呈现下降趋势;两种抑制剂均可显著降低伤后1h和2h NFκB的活性。ALLN可明显降低伤后1h肠组织中TNFα含量(P<0.01)。两种抑制剂对伤后1h和2h血浆DAO活性均无明显影响。结论早期使用泛素蛋白酶体抑制剂可降低烫伤脓毒症大鼠肠组织NFκB活性,降低肠组织中炎症反应,但对肠组织屏障功能无保护作用。

Objective To study the effect of ubiquitin-proteasome pathway inhibition on intestinal nuclear factor - κB （NF - κB） activity and tumor necrosis factor a （TNF -α） release as well as plasma diamine oxidase （I）AO） activity in rats with postburn sepsis. Methods Rats were subjected to 30~ total body surface area （TBSA） full thickness scald injury, followed by intraperitoneal injection of lipopolysaccharide （LPS） to mimic postburn sepsis. Sixty Wistar rats were randomly divided into normal control group, sepsis group, sepsis with proteasome inhibitor N - Acetyl leucinyl leucinyl norleucinal （ALLN） treatment group and sepsis with NF κB inhibitor pyrrolidine dithiocarbamate （PDTC） treatment group. NF - κB activity, TNF -α protein content, and plasma I）AO activity were determined by electrophoretic mobility shift assay （EMSA）, enzyme-linked immunosorbent assay （ELISA）, and spectrophotometric method, respectively. Results The results showed that NF- κB activity was markedly activated and reached its peak 1 hour after scalding and injection of LPS in each group （all P〈0. 01 ）. then reduced gradually. Both ALI.N and PDTC could decrease intestinal NF - κB activity at 1 hour and 2 hours after injury. TNF -α release was reduced by ALLN at 1 hour after injury （P〈0. 01 ）. Plasma DAO activity was significantly elevated after scalding and injection of LPS （P〈0.01）. Pretreatment with PDTC or ALLN could not lower the activity of DAO. Conclusion The results suggest that early treatment with inhibitor of ubiquitin-proteasome pathway might decrease the intestinal inflammatory reaction, but exert no effect on intestinal barrier function in rats with postburn seosis.