PPARγ/NF-κB信号通路在丁酸钠减轻小鼠肠缺血再灌注损伤中的作用

Role of PPARγ/NF-κB signaling pathway in sodium butyrate-induced reduction of intestinal ischemia-reperfusion injury in mice

目的评价过氧化物酶增殖物激活受体γ(PPARγ)/NF-κB信号通路在丁酸钠减轻小鼠肠缺血再灌注损伤中的作用。方法SPF级健康成年雄性C57BL/6J小鼠32只,7~9周龄,体重20~25 g,采用随机数字表法分为4组(n=8):假手术组(Sham组)、肠缺血再灌注组(IIR组)、丁酸钠组(NaB组)和PPARγ抑制剂GW9662组(GW9662组)。采用夹闭肠系膜上动脉根部45 min后恢复灌注2 h的方法制备小鼠肠缺血再灌注损伤模型。GW9662组于缺血前1 h腹腔注射GW96622 mg/kg,NaB组和GW9662组于缺血前30 min腹腔注射丁酸钠500 mg/kg。于再灌注2 h时,心脏穿刺采集血标本,然后处死小鼠,取肠组织,光镜下观察肠黏膜损伤情况并行Chiu评分;采用ELISA法检测血清和小肠组织二胺氧化酶(DAO)、IL-6及TNF-α水平;采用Western blot法检测小肠组织PPARγ和NF-κB p65的表达水平。结果与Sham组比较,IIR组Chiu评分升高,血清和小肠组织DAO、TNF-α、IL-6水平升高,PPARγ表达下调,NF-κB p65表达上调(P<0.05);与IIR组比较,NaB组小鼠Chiu评分、血清和小肠组织DAO、TNF-α、IL-6水平降低,PPARγ表达上调,NaB组及GW9662组NF-κB p65表达下调(P<0.05);与NaB组比较,GW9662组Chiu评分、血清和小肠组织DAO、TNF-α、IL-6水平升高,PPARγ表达下调,NF-κB p65表达上调(P<0.05)。结论丁酸钠减轻肠缺血再灌注损伤的机制可能与激活PPARγ/NF-κB信号通路,抑制炎症反应有关。

Objective To evaluate the role of peroxidase proliferator-activated receptorγ(PPARγ)/nuclear factor kappa B(NF-κB)signaling pathway in sodium butyrate-induced reduction of intestinal ischemia-reperfusion(I/R)injury in mice.Methods Thirty-two SPF-grade healthy adult male C57BL/6J mice,aged 7-9 weeks,weighing 20-25 g,were divided into 4 groups(n=8 each)using a random number table method:sham operation group(Sham group),intestinal I/R group(IIR group),sodium butyrate group(NaB group)and PPARγinhibitor GW9662 group(GW9662 group).The model of intestinal I/R was established by occlusion of superior mesenteric artery for 45 min followed by 2-h reperfusion in anesthetized animals.GW96622 mg/kg was intraperitoneally injected at 1 h before ischemia in GW9662 group,and sodium butyrate 500 mg/kg was intraperitoneally injected at 30 min before ischemia in NaB and GW9662 groups.Blood samples were obtained via cardiac puncture at 2 h of reperfusion,and the animals were then sacrificed.The intestinal tissues were removed for determination of diamine oxidase(DAO),tumor necrosis factorα(TNF-α)and interleukins 6(IL-6)concentrations in serum(by enzyme-linked immunosorbent assay)and the expression of PPAR and NF-κB p65(by Western blot).The damage to intestinal mucous membrane was assessed and scored according to Chiu.Results Compared with group Sham,the Chiu′s score was significantly increased,levels of DAO,TNF-αand IL-6 in serum and intestinal tissues were increased,expression of PPARγwas down-regulated,and expression of NF-κB p65 was up-regulated in group IIR(P<0.05).Compared with group IIR,the Chiu′s score,levels of DAO,TNF-αand IL-6 in serum and intestinal tissues were decreased,and expression of PPARγwas up-regulated in group NaB,and expression of NF-κB p65 was up-regulated in NaB and GW9662 groups(P<0.05).Compared with group NaB,the Chiu′s score,levels of DAO,TNF-αand IL-6 in serum and intestinal tissues were increased,and expression of PPARγwas down-regulated,and expression of NF-κB p65 was up-regulated in group GW9662(P<0.05).Conclusion The mechanism by which sodium butyrate reduces intestinal I/R injury may be related to activating PPARγ/NF-κB signaling pathway and inhibiting inflammatory responses in mice.