小檗碱干预2型糖尿病模型大鼠脑缺血再灌注损伤

Berberine alleviates ischemia/reperfusion injury in type 2 diabetic rats

背景:既往研究提示小檗碱可减轻脑缺血再灌注损伤。目的:探讨小檗碱对2型糖尿病大鼠脑缺血再灌注损伤的影响及其分子机制。方法:实验方案经海南省中医院伦理委员会批准。用低剂量链脲佐菌素30 mg/kg每隔1 d大鼠腹腔注射2次,处理8周建立2型糖尿病模型,选取平均血糖≥11.1 mmol/L造模成功的雄性SD大鼠90只,随机分为对照组、缺血/再灌注组和缺血/再灌注+小檗碱组,每组30只。对照组和缺血/再灌注组大鼠经生理盐水灌胃,缺血/再灌注+小檗碱组用小檗碱200 mg/(kg·d)灌胃,处理7 d后,后2组采用大脑中动脉阻断2 h,再灌注12 h建立大脑中动脉缺血再灌注模型。苏木精-伊红染色和透射电镜观察脑梗死体积;采用ELISA检测梗死区超氧化物歧化酶、丙二醛和一氧化氮水平;采用TUNEL法检测脑细胞凋亡情况;Westernblot检测PI3K、Akt和磷酸化Akt(p-Akt)蛋白的表达。结果与结论:①与缺血/再灌注组比较,缺血/再灌注+小檗碱组脑梗死体积明显减少(P<0.05),超氧化物歧化酶水平明显升高,丙二醛和一氧化氮的表达明显降低;②与缺血/再灌注组比较,缺血/再灌注+小檗碱组脑梗死区细胞凋亡减少,Bcl-2表达增加,cleaved-Caspase3和Bax表达降低;③与缺血/再灌注组相比,小檗碱可使缺血/再灌注+小檗碱组PI3K和p-Akt的表达水平明显上调;④结果说明,小檗碱可通过激活PI3K-Akt信号通路,在2型糖尿病大鼠脑缺血模型中发挥抗凋亡作用,减轻脑缺血/再灌注损伤。

BACKGROUND:Berberine has been shown to alleviate cerebral ischemia/reperfusion injury.OBJECTIVE:To investigate the effects of berberine on the cerebral ischemia/reperfusion injury in type 2 diabetic rats and its molecular mechanism.METHODS:The study was approved by the Ethical Committee of Chinese Medicine Hospital of Hainan Province.The rats underwent intraperitoneal injection of 30 mg/kg streptozotocin,twice every other day,for 8 weeks to establish the type 2 diabetic model.Ninety male Sprague-Dawley rats with average blood sugar≥11.1 mmol/L were selected and randomly divided into control,ischemia/reperfusion injury and ischemia/reperfusion injury+berberine groups(n=30/group).The rats in the former two groups were given the normal saline via gavage,and the ischemia/reperfusion injury+berberine group received the 200 mg/(kg·d)via gavage.After 7 days of treatment,the latter two group rats were subjected to middle cerebral artery occlusion for 2 hours and reperfusion for 12 hours to establish the model of middle cerebral artery ischemia/reperfusion.Hematoxylin-eosin staining and transmission electron microscopy were used to observe the volume of cerebral infarction.The levels of superoxide dismutase,malondialdehyde and nitric oxide in the infarct area were detected by ELISA.The brain cell apoptosis was detected by TUNEL staining.The expression levels of PI3K,Akt and phosphorylated Akt were detected by western blot assay.RESULTS AND CONCLUSION:(1)Compared with the ischemia/reperfusion group,the volume of cerebral infarction in the ischemia/reperfusion+berberine group was significantly reduced(P<0.05),the superoxide dismutase level was significantly increased,and the malondialdehyde and nitric oxide levels were significantly decreased.(2)Compared with the ischemia/reperfusion group,the ischemia/reperfusion+berberine group had less apoptosis,higher expression of Bcl-2 and lower expression of cleaved Caspase-3 and Bax.(3)Compared with the ischemia/reperfusion group,the ischemia/reperfusion+berberine group had increase in the expression levels of PI3K and p-Akt.(4)These results indicate that berberine can play an anti-apoptotic role by activating PI3K-Akt signaling pathway and alleviate brain ischemia/reperfusion injury in type 2 diabetic rats.