黄芪预处理对大鼠肠系膜缺血再灌注损伤后细胞凋亡的影响及其机制研究

Effect and Mechanism of Astragalus Pretreatment on Apoptosis in Intestinal Ischemia-reperfusion Rats

目的:研究黄芪预处理对大鼠肠系膜缺血再灌注损伤后细胞凋亡的影响,并探讨其可能的作用机制。方法:选取120只实验用大鼠随机分假手术组、模型组、银杏叶提取物(3.15 mg/kg)预处理组与黄芪(5、10和20 g/kg)预处理组;术前7天开始腹腔注射给药(1次/d),假手术组和模型组给予等体积生理盐水。采用剥离并夹闭肠系膜上动脉45min的方法建立大鼠肠系膜缺血再灌注损伤模型;再灌注2 h后,测定肠组织含水量,TUNEL法观察肠系膜细胞凋亡状况并计算凋亡指数(Apoptosis Index,AI);RT-PCR法测定肠组织中AKT m RNA、Bcl-2 m RNA、Bax m RNA表达;测定肠组织中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性与丙二醛(MDA)含量,Western blot法测定肠组织中NF-κB蛋白表达并进行半定量分析。结果:与模型组比较,黄芪(10、20 g/kg)预处理组大鼠肠组织含水量显著降低;黄芪预处理组大鼠肠细胞凋亡状况较模型组均明显改善,其中10、20 g/kg预处理组AI显著降低;黄芪(10、20 g/kg)预处理组大鼠肠组织中Bcl-2 m RNA表达显著升高而Bax m RNA显著降低、Bcl-2/Bax比值显著升高,SOD和CAT活性显著升高、MDA含量显著降低,NF-κB蛋白表达显著上调;黄芪(20g/kg)预处理组AKT m RNA表达显著升高;上述差异均具有统计学意义(P<0.05,P<0.01)。结论:黄芪预处理可能通过调节凋亡相关基因(AKT、Bcl-2、Bax)和蛋白(NF-κB)表达而对肠系膜缺血再灌注损伤后细胞凋亡具有一定的抑制作用。

Objective ： To investigate the effect and mechanism of Astragalus pretreatment on apoptosis in intesti- nal ischemia -reperfusion rats. Methods：One hundred and twenty experimental rats were randomly devided into six groups ： sham operation group, model group, Ginkgo biloba extract （ GB, 3. 15 mg/kg） pretreatment group and Astragalus（5, 10, 20 g/kg） pretreatment groups. Severn days before surgery, the drugs were given by intraperitoneal injection, once a day. The rat models were made by clipping superior mesenteric artery; two hours later, the water content was detected; the apoptosis of intestinal cells was observed by TUNEL staining and the apoptosis index （AI） was calculated ; the expressions of AKT mRNA, Bcl - 2 mRNA, Bax mRNA were detected and the ratio of Bcl - 2/Bax was calculated ; the activity of SOD, CAT and the content of MDA in intestinal tissue were detected; the expression of NF - KB was detected by Western blot and was Semi - quantitatively analyzed. Results： Compared with those in model group, the water contents in Astragalus（ 10, 20 g/kg）pretreatement groups were significantly decreased; the intestinal cell apoptosis in Astragalus pre- treatement groups was significantly improved, and the AI in Astragalus（ 10, 20g/kg）pretreatement groups was significantly decreased; the expressions of Bcl -2 mRNA were significantly increased and the Bax mRNA was significantly decreased; the ratio of Bcl -2/Bax was significantly increased; the activity of SOD, CAT in in- testinal tissue was significantly increased and the content of MDA was significantly decreased; the expressions of AKT mRNA in Astragalus （20g/kg）pretreatement group were significantly decreased; all the above differ- ences were significant （P 〈 0.05, P 〈 0.01 ）. Conclusion ： Astragalus pretreatment has inhibitive effects on ap- optosis in intestinal ischemia - reperfusion rats, which may be related to its effects of regulating the expression of apoptosis - related genes and proteins.