N-乙酰半胱氨酸在减轻大鼠重症急性胰腺炎肠损伤中的作用

N-acetylcysteine ameliorates severe acute pancreatitisassociated intestinal injury in rats

目的:观察N-乙酰半胱氨酸(N-acetylcysteine,N A C)对重症急性胰腺炎(severe acute pancreatitis,SAP)大鼠血浆肿瘤坏死因子(tumor necrosis factor α,TNF-α)、白细胞介素1(interleukin-1β,IL-1β)、IL-10及小肠组织细胞间黏附分子1(intercellular cell adhesionmolecule-1,ICAM1)表达的影响,并探讨其对大鼠SAP相关肠损伤保护作用的机制.方法:72只Wistar大鼠随机分为假手术组(SO组)、SAP组及NAC干预组(NAC组).每组再分为6、12、24 h共3个时相点,每个时相点各8只大鼠.通过胰胆管逆行注射5%牛磺胆酸钠制作大鼠SAP模型,SO组用同样方法经胰胆管逆行注射生理盐水,NAC组大鼠在制作SAP模型前1 h经腹腔注射NAC,SO组及SAP组在术前1 h经腹腔注射同NAC等体积的生理盐水.动物分别于术后6、12、24 h麻醉后取材,检测血浆淀粉酶(plasma amylase,AMY)、内毒素、D-乳酸,二胺氧化酶(diamine oxidase,DAO)、TNF-α、IL-1β及IL-10含量,观察小肠组织病理学变化并进行评分,实时荧光定量PCR(Real-time PCR)检测小肠组织ICAM1mRNA的表达,Western blot法检测小肠组织ICAM1蛋白变化.结果:NAC组各时相点大鼠AMY、TNF-α及IL-β水平均较SAP组各对应时相点降低,IL-10水平则明显增高,内毒素、DAO和D-乳酸在12和24 h时也明显降低;SO组大鼠小肠组织无明显病理学改变,NAC组大鼠小肠病理改变较SAP组明显改善,小肠组织病理学评分在12及24 h亦明显降低.NAC组大鼠小肠组织中ICAM1 mRNA(6 h:1.13±0.28 vs 2.37±0.63;12 h:1.27±0.34 vs 2.94±0.82;24 h:1.19±0.26 vs 2.68±0.95,均P<0.05)及蛋白(6 h:0.74±0.11 vs 1.04±0.25;12 h:0.88±0.17 vs1.25±0.33;24 h:0.75±0.13 vs 1.18±0.22,均P<0.05)的表达与SAP组相应时相点比较均明显减弱.结论:NAC可以减轻SAP大鼠肠损伤,其机制除其可以抑制TNF-α、IL-1β并促进IL-10的释放外,还可能与其对小肠组织ICAM1表达的调节作用有关.

AIM：To investigate the effects of treatment with n-acetylcysteine（NAC） on plasma levels of tumor necrosis factor-α（TNF-α,interleukin-1β（IL-1βand IL-10 and ICAM1 expression in small intestine tissue in rats with severe acute pancreatitis（SAP） and to explore the possible mechanisms involved.METHODS：Seventy Wistar rats were randomly divided into a sham operation group（SO,n = 24）,a SAP group（n = 24） and a NAC treatment group（n = 24）.SAP was induced in rats by injecting 5.0% sodium taurocholate into the biliary-pancreatic duct.Rats in the SO group were given an infusion of normal saline instead.Rats in the NAC group underwent SAP induction and were given an intraperitoneal injection of NAC 1 hour before the operation,and rats in the SO group and SAP group were given an intraperitoneal injection of normal saline.Eight rats were sacrificed 6,12 or 24 h after operation in each group.Plasma levels of amylase（AMY）,endotoxin,diamine oxidase（DAO）,D-lactic acid,TNF-α,IL-1β and IL-10 were measured.Pathologic changes in the small intestine were observed and scored.ICAM1 mRNA and protein expression in the small intestine was tested by real-time PCR and Western blot,respectively.RESULTS：Compared to the SAP group,plasma levels of AMY,TNF-α and IL-β were significantly lower at all three time points（all P0.05） and serum levels of endotoxin,DAO and D-lactic acid were significantly lower at 12 and 24 h（both P0.05） in the NAC group.Serum levels of IL-10 in the NAC group were increased compared to the SAP group at all three time points.The pathology score of the small intestinal was significantly lower in the NAC group than the SAP group at 12 and 24 h.Although the mRNA expression of ICAM1 was increased at each time point in the SAP group compared with the SO group,it was significantly decreased in the NAC group compared with the SAP group（6 h：1.13±0.28 vs 2.37±0.63;12 h：1.27±0.34 vs 2.94±0.82;24 h：1.19±0.26 vs 2.68±0.95;all P0.05）.The protein expression of ICAM1 had the same trend as the mRNA expression between the NAC and SAP groups（6 h：0.74±0.11 vs 1.04±0.25;12 h：0.88±0.17 vs 1.25±0.33;24 h：0.75±0.13 vs 1.18±0.22;all P0.05）.CONCLUSION：Administration of NAC ameliorates severe acute pancreatitis-associated intestinal injury in rats possibly by regulating plasma levels of TNF-α,IL-1β and IL-10 and inhibiting ICAM1 expression in the small intestine.