信号转导和转录激活因子3与基质金属蛋白酶9在肠屏障功能障碍小鼠肠组织的表达及其关系

Expression of signal transducer and activator of transcription 3 and matrix metalloproteinase 9 in intestinal tissue of mice with intestinal barrier dysfunction and their relationship

目的探讨信号转导和转录激活因子3(STAT3)与基质金属蛋白酶-9(MMP-9)在脂多糖诱导炎症性损伤致肠屏障功能障碍中的作用及其关系。方法 32只8~9周龄雄性BALB/c小鼠随机数字表法分为Stattic 7 d组、Stattic 14 d组、假手术组(Sham组)和空白对照组(NC组), 每组8只。Stattic 7 d组和Stattic 14 d组分别给予Stattic 15 mg/(kg·d)腹腔注射7 d和14 d, Sham组给予同等容量生理盐水腹腔注射14 d;NC组不做预处理。预处理后4组小鼠单次腹腔注射脂多糖(LPS), 12 h后观察存活情况并取材, 比较各组小鼠血清中白细胞介素-6(IL-6)及二胺氧化酶(DAO)水平、小肠Chiu’s评分、肠组织STAT3、磷酸化STAT3(p-STAT3)、MMP-9及闭合蛋白Occludin表达情况。组间比较采用χ^(2)/F检验。结果 Sham组和NC组血清DAO高于Stattic 7 d组和Stattic 14 d组[(125.71±31.10)、(125.91±40.54)、(62.86±14.79)、(58.95±22.35) ng/ml, F=18.329, P<0.01], 差异有统计学意义;Sham组和NC组Chiu’s评分高于Stattic 7 d组和Stattic 14 d组[(2.54±0.53)、(2.24±0.38)、(1.10±0.38)、(0.89±0.30)分, F=32.303, P<0.01], 差异有统计学意义;p-STAT3、MMP-9, Sham组和NC组免疫组织化学阳性面积高于Stattic 7 d组和Stattic 14 d组[(10.34±2.55)、(18.60±2.61);(17.34±2.86)、(19.84±3.50);(9.48±2.64)、(8.53±4.04);(10.34±2.55)、(9.71±3.37)%, F=29.025、23.656, P<0.01], 差异有统计学意义;p-STAT3、MMP-9, Sham组和NC组蛋白相对表达量高于Stattic 7 d组和Stattic 14 d组(0.35±0.06、0.74±0.13;0.32±0.07、0.73±0.11;0.19±0.02、0.36±0.11;0.20±0.04、0.40±0.09), 差异有统计学意义(F=21.852、27.125, P<0.01), Stattic 7 d组和Stattic 14 d组Occludin高于Sham组和NC组(0.39±0.09、0.46±0.10、0.21±0.06、0.21±0.16, F=23.504, P<0.01), 差异有统计学意义。结论 IL-6/JAK2/STAT3通路参与肠黏膜中MMP-9的表达调控, 并影响肠屏障功能。

Objective To investigate the role of signal transducer and activator of transcription 3(p-STAT3)and matrix metalloproteinase 9(MMP-9)in intestinal barrier dysfunction induced by lipopolysaccharide(LPS)-induced inflammatory injury.Methods Totally,32 healthy male mice were divided into 4 groups:stattic 7 d,stattic 14 d,sham and NC.Stattic 7 d group and Stattic 14 d group were given stattic 15 mg/(kg·d)intraperitoneal injection for 7 days and 14 days respectively,and sham group was given the same volume of normal saline intraperitoneal injection for 14 days.NC group did not perform pretreatment.After pretreatment,the mice in the 4 groups were injected with LPS intraperitoneally.After 12 h,the survival was observed and the mice were killed.The levels of interleukin-6(IL-6)and diamine oxidase(DAO),Chiu’s score,the expression of p-STAT3,phosphorylated STAT3(p-STAT3),MMP-9 and occludin were compared.F andχ^(2) test were used.Results Serum DAO[(125.71±31.10),(125.91±40.54),(62.86±14.79),(58.95±22.35)ng/ml]in sham group and NC group was significantly higher than that in Stattic 7 d group and Stattic 14 d group(F=18.329,P<0.01);Chiu’s score(2.54±0.53,2.24±0.38,1.10±0.38,0.89±0.30)in sham group and NC group was higher than in Stattic 7 d group and Stattic 14 d group,the difference was statistically significant(F=32.303,P<0.01);There were significant differences in immunohistochemical positive areas of p-STAT3 and MMP-9[(10.34±2.55),(18.60±2.61);(17.34±2.86),(19.84±3.50);(9.48±2.64),(8.53±4.04);(10.34±2.55),(9.71±3.37)%]between sham group and NC group(F=29.025,23.656,P<0.01);There was significant difference in the relative expression of p-STAT3 and MMP-9 proteins(0.35±0.06,0.74±0.13;0.32±0.07,0.73±0.11;0.19±0.02,0.36±0.11;0.20±0.04,0.40±0.09)between sham group and NC group(F=21.852,27.125,P<0.01).The expression of occludin in Stattic 7 d group and Stattic 14 d group was significantly higher than in sham group and NC group(0.39±0.09,0.46±0.10,0.21±0.06,0.21±0.16)(F=23.504,P<0.01).Conclusion IL-6/JAK2/STAT3 pathway is involved in the regulation of MMP-9 expression in intestinal mucosa and affects the function of intestinal barrier.