急性坏死性胰腺炎肠黏膜NFκB介导的细胞因子过度表达及生长激素的作用

Nuclear factor κB-mediated cytokines over-expression in intestinal mucosa of acute necrotizing pancreatitis and influence of growth factor in rats

目的 本研究旨在动态观察急性坏死性胰腺炎 (ANP)大鼠肠黏膜核因子κB(NFκB)及其介导的细胞因子 ,包括肿瘤坏死因子α(TNFα)、白介素 1(IL 1β)、诱导型一氧化氮合成酶 (iNOS)、细胞间黏附分子 (ICAM 1)和单核细胞趋化蛋白 (MCP 1)mRNA的变化 ,探讨其在ANP并发肠道衰竭发生中的作用 ;并观察生长激素 (GH)对NFκB活化及细胞因子表达的下调作用。方法 SD大鼠72只 ,随机分为三组 :假手术组 (SO) ;ANP组 ;ANP +GH组。GH治疗组术后皮下注射GH溶液(0 75U/kg体重 ) ,非治疗组则注射等容积生理盐水作对照。大鼠胆胰管内逆行注射 5 %牛磺胆酸钠溶液制备ANP模型。提取肠组织RNA ,逆转录聚合酶链反应 (RT PCR)研究术后 6,12 ,2 4h肠黏膜TNFα、IL 1β、iNOS、ICAM 1、MCP 1mRNA表达。术后 3 ,6,12 ,2 4h免疫组化法检测肠黏膜NFκB的活化情况。结果 ANP组大鼠肠黏膜TNFα、IL 1β、iNOS、ICAM 1和MCP 1mRNA表达较SO组增高 ,其中TNFα和IL 1βmRNA表达于术后 6h达峰值 ,且较SO组差异显著 (TNFα :1 0 3± 0 17vs0 3 4± 0 0 7;IL 1β :0 91± 0 0 8vs 0 3 9± 0 0 6,P <0 0 5 ) ;iNOS和ICAM 1mRNA表达于术后 12h达峰值 ,较SO组差异显著 (iNOS :0 62± 0 10vs 0 0 4± 0 0 2 ;ICAM 1:1 48± 0 3

Objective To investigate the roles of activated nuclear factor κB (NFκB) and NFκB mediated cytokines over expression in intestinal mucosa on intestinal failure during acute necrotizing pancreatitis (ANP) and the down regulation of growth hormone (GH) upon them. Methods ANP was induced in SD rats by injection of 5% sodium taurocholate into biliopancreatic duct. Laparotomized rats without induction of ANP were employed to serve as the controls. The rats with ANP treated by GH were subscutaneously injected with 0 75 U/kg human recombinant GH for only once after the operation. All the rats were divided into three groups of control, ANP and ANP+GH. TNFα, IL 1β, iNOS, ICAM 1, MCP 1 mRNA expression in the intestinal mucosa was determined by RT PCR at 6, 12 and 24 h and NFκB in the intestinal mucosa detected with immunohistochemistry at 3, 6, 12 and 24 h after operation. Results The expression of TNFα, IL 1β, iNOS, ICAM 1, MCP 1 mRNA was significantly higher in ANP group than in the control. TNFα and IL 1β mRNA reached its peak at 6 h while iNOS and ICAM 1 mRNA expression did at 12 h postoperatively. The expression of MCP 1 mRNA was up regulated and significantly different from that in the control group (P<0 05). The treatment with GH markedly down regulated TNFα, IL 1β, iNOS, ICAM 1 and MCP 1 mRNA expression. Activated NFκB was almost absent from intestinal mucosa in the control group but remarkably increased in ANP rats, especially at 3h postoperatively. The positive staining cells mainly distributed near the tip of the intestinal villi. The degree of NFκB activation was decreased in GH treated group as compared with ANP group. Conclusions Activation of NFκB and NFκB mediated cytokine expression is one of the major factors for intestinal failure in ANP. The notable anti inflammatory effects of GH for down regulating cytokine transcription in infected intestinal mucosa of ANP rats might be due to inhibition of NFκB activation.