罗格列酮对溃疡性结肠炎大鼠的保护作用及机制研究

Study on Protective Effect and Mechanism of Rosiglitazone on Ulcerative Colitis Rats

目的:探讨罗格列酮对溃疡性结肠炎大鼠的保护作用及其作用机制。方法:三硝基苯磺酸(TNBS)/乙醇复合法用于建立大鼠溃疡性结肠炎模型,8周龄健康成年雄性SD大鼠15只,随机分成3组,每组5只,分别为对照组、溃疡组和罗格列酮组。对照组为生理盐水灌肠和灌胃,模型组为TNBS/乙醇混合液灌肠和生理盐水灌胃,罗格列酮组则从灌肠造模成功后的第二天起,每天采用罗格列酮灌胃给药1次(5 mg/kg)。观察大鼠的一般活动状态,并记录各组大鼠的疾病活动指数(DAI),于灌肠后第60天处死大鼠,镜下观察并记录各组大鼠的结肠黏膜损伤指数(CDMI),苏木色精-伊红法(HE)染色后,镜下观察各组大鼠的结肠组织病理学改变,并进行组织学评分(HS)。生化法用于检测大鼠结肠组织中超氧化物歧化酶(SOD)、丙二醛(MDA)和髓过氧化物酶(MPO)的含量。实时荧光定量聚合酶链式反应(qRT-PCR)和免疫组化(IHC)法分别检测各组大鼠结肠组织中过氧化物酶增殖激活受体-γ(PPARγ)、核转录因子_(-κ)B(NFκB)和肿瘤坏死因子-α(TNF-α)的mRNA和蛋白表达水平。结果:与对照组相比,溃疡组的DAI、CDMI和HS评分均显著增加(P<0.05);SOD含量显著降低,MDA和MPO的含量显著增加(P<0.05);PPARγ的mRNA和蛋白表达量显著降低(P<0.05);NFκB和TNF-α的mRNA和蛋白表达量显著增加(P<0.05)。与溃疡组相比,罗格列酮组的大鼠DAI、CDMI和HS评分均显著降低(P<0.05);结肠组织中SOD含量显著增加,MDA和MPO的含量显著降低(P<0.05);PPARγ的mRNA和蛋白表达量显著增加(P<0.05);NFκB和TNF-α的mRNA和蛋白表达量显著降低(P<0.05)。结论:罗格列酮可以通过增加SOD和PPARγ表达,降低MDA、MPO、NFκB和TNF-α表达来缓解炎症反应,对溃疡性结肠炎起到保护作用。

Objective： To explore the protective effect of rosiglitazone on ulcerative colitis rats and its mechanism. Methods：Trinitrobenzene sulfonic acid（TNBS）/ethanol complex was used to establish rat model of ulcerative colitis.15 male SD rats aged 8 weeks were randomly divided into control group（n=5）, ulcer group（n=5） and rosiglitazone group（n=5）. The rats in the control group were treated with saline enema and intragastric administration. The rats in the model group, with TNBS/ethanol mixture and saline. The rosiglitazone group was administered with rosiglitazone（5 mg/kg） once a day from the second day after the success of establishing rat model of ulcerative colitis by enema.The general activities of the rats were observed and the disease activity indexes（DAI） of each group were recorded. The rats were sacrificed on the sixtieth day after enema. The histopathological changes of colonic tissue were observed under microscope. The histological score（HS） was performed. The content of superoxide dismutase（SOD）, malondialdehyde（MDA） and myeloperoxidase（MPO） in colonic tissue of rats were detected by biochemical method. Real-time fluorescence quantitative polymerase chain reaction（qRT-PCR） and immunohistochemistry（IHC） were used to detect the expression of peroxisome proliferator activated receptor-γ（PPARγ）, nuclear factor_（-κ）B（NFκB） and tumor necrosis factor-α（TNF-α） mRNA and protein in colon tissue of each group.Results： Compared with the control group, the DAI,CDMI and HS scores of ulcer group were significantly increased（P0.05）, the content of SOD was significantly decreased, the content of MDA and MPO were significantly increased（P0.05）, the expression of PPARγ mRNA and protein were decreased significantly（P0.05）, the expression of NFκB and TNF-α mRNA and protein were increased significantly（P0.05）. Compared with the ulcer group, the DAI, CDMI and HS scores of the rosiglitazone group were significantly decreased（P0.05）; the content of SOD in the colon tissue was significantly increased, the content of MDA and MPO were significantly decreased（P0.05）, the expression of PPARγ mRNA and protein were significantly increased（P0.05）, the expression of NFκB and TNF-α mRNA and protein were significantly decreased（P0.05）. Conclusion： Rosiglitazone can alleviate the inflammatory reaction by increasing the expression of SOD and PPARγ and decreasing the expression of MDA, MPO, NFκB and TNF-α so as to play a protective role in ulcerative colitis.