黄芩苷减轻大鼠肠缺血再灌注损伤及对Nrf2、HO-1表达的影响

Baicalin attenuates intestinal ischemia/reperfusion injury and alters intestinal expression of Nrf2 and HO-1 in rats

目的:研究黄芩苷对大鼠肠缺血再灌注(intestinal ischemia-reperfusion,IIR)损伤的保护作用及机制.方法:♂Wistar大鼠32只,随机分为假手术(sham-operated,SO)组、黄芩苷(baicalin,BA)组、肠缺血再灌注(IIR)组、黄芩苷+肠缺血再灌注(BA+IIR)组.BA组和BA+IIR组于造模前30 min腹腔注射黄芩苷100 mg/kg体质量,SO组和IIR组注射等量生理盐水.再灌注2 h后取材,HE染色观察小肠组织损伤程度,水溶性四唑盐1(water soluble tetrazolium s a l t 1,W S T-1)法测定血清超氧化物歧化酶(superoxide dismutase,SOD)活性,硫代巴比妥酸法测定血清丙二醛(malondialdehyde,MDA)含量,ELISA法检测血浆D-乳酸含量,免疫组织化学(immunohistochemistry,IHC)和Western blot法检测核因子相关因子2(NF-E2-related factor 2,Nrf2)、血红素加氧酶1(heme oxygenase 1,HO-1)蛋白表达.结果:IIR组与SO组比较,小肠黏膜损伤Chiu氏评分升高(3.99±0.24 vs 0.30±0.08,P<0.01),血清S O D活性降低(100.08 U/m L±3.20 U/mL vs 136.88 U/mL±5.93 U/mL,P<0.01),MDA含量增加(3.41 nmol/mL±0.23nmol/mL vs 1.59 nmol/mL±0.25 nmol/mL,P<0.01),血浆D-乳酸含量增多(174.27 ng/mL±33.84 ng/mL vs 52.40 ng/mL±12.12 ng/mL,P<0.01),小肠组织中N r f2、H O-1表达增加(IHC:0.326±0.024 vs 0.289±0.041,0.298±0.025 vs 0.258±0.027,P<0.05;WB:1.062±0.056 vs 0.584±0.048,1.019±0.041 vs 0.592±0.037,P<0.01).BA组小肠组织Nrf2、HO-1表达比SO组显著增加(IHC:0.322±0.028vs 0.289±0.041,0.284±0.009 vs 0.258±0.027,P<0.05;WB:1.077±0.038 vs 0.584±0.048,1.027±0.042 vs 0.592±0.037,P<0.01).BA+IIR组与IIR组相比,小肠黏膜损伤Chiu氏评分降低(2.95±0.26 vs 3.99±0.24,P<0.01),血清SOD活性升高(116.11 U/mL±4.12 U/mL vs 100.08 U/mL±3.20 U/mL,P<0.01),MDA含量减少(3.09 nmol/mL±0.15 nmol/mL vs 3.41nmol/mL±0.23 nmol/mL,P<0.01),血浆D-乳酸含量减少(108.04 ng/mL±20.19 ng/mL vs174.27 ng/mL±33.84 ng/mL,P<0.01),小肠组织Nrf2、HO-1表达增加(IHC:0.371±0.024 vs0.326±0.024,0.336±0.031 vs 0.298±0.025,P<0.01;WB:1.541±0.100 vs 1.062±0.056,1.458±0.071 vs 1.019±0.041,P<0.01).结论:黄芩苷对大鼠肠缺血再灌注损伤有良好的保护作用,其机制可能是通过激活核因子相关因子2-抗氧化反应元件(NF-E2-related factor 2-antioxidant response element,Nrf2-ARE)通路进而增加抗氧化酶SOD、HO-1表达实现的.

AIM： To investigate the protective effects of baicalin against intestinal ischemia-reperfusion （IIR） injury in rats.METHODS： Thirty-two male Wistar rats were randomly and equally divided into four groups： control （SO）, baicalin （BA）, IIR, and baicalin ＋ IIR （BA ＋ IIR）. IIR was induced by clamping the superior mesenteric artery （SMA） for 60 min and restoring blood supply for two hours. The rats in the SO and BA groups underwent a laparotomy, and the SMA was separated without occlusion. The rats in the BA and BA ＋ IIR groups were given baicalin （100 mg/kg, 1 mL） by introperitoneal injection 30 min before model creation. The rats in the SO and IIR groups were given normal saline （1 mL）. Intestinal histopathologic changes were examined. Serum superoxide dismutase （SOD） and malondialdehyde （MDA） levels were determined by WST and thiobarbituric acid method, respectively, and plasma D-lactic acid level was assayed by ELISA. The expression of NF-E2-related factor 2 （Nrf2） and heme oxygenase 1 （HO-1） in intestinal tissues was determined by immunohistochemistry （IHC） and Western blot （WB）.RESULTS： In the IIR group, the Chiu’s score （3.99 ± 0.24 vs 0.30 ± 0.08, P 〈 0.01）, serum MDA level （3.41 ± 0.23 vs 1.59 ± 0.25, P 〈 0.01） and plasma D-lactic acid level （174.27 ± 33.84 vs 52.40 ± 12.12, P 〈 0.01） were significantly higher than those in the SO group. Nrf2 and HO-1 expression in intestinal tissues in the IIR group was significantly higher than that in the SO group （IHC： 0.326 ± 0.024 vs 0.289 ± 0.041, 0.298 ± 0.025 vs 0.258 ± 0.027, P 〈 0.05; WB： 1.062 ± 0.056 vs 0.584 ± 0.048, 1.019 ± 0.041 vs 0.592 ± 0.037, P 〈 0.01）. In the IIR group, serum SOD activity decreased significantly compared with the SO group （100.08 ± 3.20 vs 136.88 ± 5.93, P 〈 0.01）. In the BA group, Nrf2 and HO-1 expression in intestinal tissues increased significantly in comparison with the SO group （IHC： 0.322 ± 0.028 vs 0.289 ± 0.041, 0.284 ± 0.009 vs 0.258 ± 0.027, P 〈 0.05; WB： 1.077 ± 0.038 vs 0.584 ± 0.048, 1.027 ± 0.042 vs 0.592 ± 0.037, P 〈 0.01）. Compared with the IIR group, intestinal tissue injury was significantly reduced （2.95 ± 0.26 vs 3.99 ± 0.24, P 〈 0.01）, serum MDA level （3.09 ± 0.15 vs 3.41 ± 0.23, P 〈 0.01） and plasma D-lactic acid decreased significantly （108.04 ± 20.19 vs 174.27 ± 33.84, P 〈 0.01）, and serum SOD activity （116.11 ± 4.12 vs 100.08 ± 3.20, P 〈 0.01） and expression of Nrf2 and HO-1 in intestinal tissues increased significantly （IHC： 0.371 ± 0.024 vs 0.326 ± 0.024, 0.336 ± 0.031 vs 0.298 ± 0.025, P 〈 0.01; WB： 1.541 ± 0.100 vs 1.062 ± 0.056, 1.458 ± 0.071 vs 1.019 ± 0.041, P 〈 0.01） in the IIR ＋ BA group. CONCLUSION： Our data suggest that baicalin alleviates IIR injury possibly by activating the Nrf2-ARE pathway.