四逆汤对大鼠肠缺血再灌注损伤后肠黏膜的保护效应

目的:探讨四逆汤(SND)对大鼠肠缺血再灌注(I/R)后肠黏膜的保护效应及机制。方法:SD大鼠随机分为对照组(仅分离不阻断肠系膜上动脉)、模型组(阻断肠系膜上动脉1 h后再灌注3 h)、SND高剂量(6 g.kg^-1.d^-1)及低剂量(3 g.kg^-1.d^-1)组。SND组大鼠连续灌胃3 d后手术。取回肠末端组织行光镜检查,并行肠黏膜组织Chiu’s评分,计算肠含水率;TUNEL法检测肠黏膜上皮细胞凋亡情况,检测肠黏膜组织超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量的变化,免疫组化染色法检测B细胞淋巴瘤/白血病-2(Bcl-2)蛋白表达。结果:SND预先给药能明显减轻肠黏膜组织病理损害,显著降低Chiu’s评分、肠含水率、肠黏膜细胞凋亡指数及MDA含量(P<0.01),升高SOD活性及Bcl-2蛋白表达(P<0.01),但SND两个剂量组间上述指标均无显著性差异(P>0.05)。相关分析表明,模型组及SND两个剂量组肠黏膜组织SOD活性与肠黏膜上皮细胞凋亡指数呈显著的负相关(r分别为0.775,0.796与0.712,P<0.01)。模型组与低剂量组Bcl-2蛋白表达量与肠黏膜上皮细胞凋亡指数亦呈显著负相关(r分别为0.751与0.698,P<0.01)。结论:SND预先给药对肠I/R后肠黏膜具有保护作用,可能与其清除氧自由基、促进Bcl-2蛋白表达来抑制肠黏膜细胞凋亡有关。

Study on Sini decoction in treatment of intestinal ischemia-reperfusion injury in rats:mechanism relating to oxygen radical and Bcl-2 protein

OBJECTIVE: To investigate the protective effect of Sini decoction (SND) on intestinal mucosa in rats with intestinal ischemia reperfusion (I/R) and the mechanism relating to oxygen radical and Bcl-2 protein expression. METHOD: Thirty-two SD rats of both sexes were randomly divided into 4 equal groups: (1) control group in which sham operation was performed; (2) model group in which intestinal I/R was produced by clamping super mesenteric artery(SMA) for 1 hour and declamping SMA for 3 hours; (3) SND low dose group in which SND(3 g x kg(-1) x d(-1)) was given via stomach tube for 3 days before operation; (4) SND high dose group in which SND(6 g x kg(-1) x d(1)) was given via stomach tube, for 3 days before operation. A strip of small intestine was taken from distal end of ileum for light microscopic examination, Chiu's score and the detection of intestinal water content (IWC). Apoptosis of intestinal mucosa cell was examined by TUNEL method. Superoxide dismutase (SOD) activity, malondisldehyde (MDA) concentration of intestinal mucosa were detected. The protein express of Bcl-2 of intestinal mucosa was analyzed by immunochemistory. RESULT: Intestinal /R resulted in histopathological changes in intestinal mucosa, increased Chiu's scores, apoptosis index, IWC and MDA content, and reduced SOD activity and the protein expression of Bcl-2 significantly (P < 0.01). The pretreatment of SND could attenuate the above changes significantly (P < 0.01), but there was no significant difference for the above variables between SND low dose group and SND high dose group (P > 0.05). Apoptosis index was significantly negatively correlative to SOD activity in model group and two SND groups. There were significantly negative correlation between apoptosis index and protein expression of Bcl-2 in model group and SND low dose group. CONCLUSION: SND can attenuate intestinal mucosa injury following intestinal U/R, which is related to reducing intestinal mucosa cell apoptosis by removing oxygen free radical and upregulating the protein expression of Bcl-2.