腺苷预处理对大鼠脑组织缺血再灌注损伤的干预作用及其机制

Intervention effect of adenosine preconditioning on cerebral ischemia-reperfusion injury in rats and its mechanism

目的观察腺苷预处理对大鼠脑组织缺血再灌注损伤的干预作用,并探讨其相关机制。方法健康成年雄性SD级大鼠180只,随机分为假手术组、模型组、实验组,每组60只。实验组大鼠造模前3 d腹腔注射腺苷注射液每次2 mL、每天1次,假手术组和模型组大鼠于同时点腹腔注射生理盐水2 mL;模型组和实验组采用改良线栓法制作大脑中动脉栓塞模型,假手术组仅分离大脑中动脉,不进行阻断血供操作。术后24 h测算各组大鼠脑梗死体积占比,观察海马组织病理变化;分别于术后2、6、24、48 h采用qRT-PCR法检测病灶脑组织中的miRNA-125b,采用Western blotting法检测病灶脑组织中的B细胞淋巴瘤2(Bcl-2)、磷酸化蛋白激酶B(p-AKT)、p53蛋白。结果模型组、实验组脑梗死体积占比高于假手术组,实验组低于模型组(P均<0.05)。实验组神经元细胞病理表现较模型组明显减轻,大部分细胞存活,细胞膜完整,细胞核及核仁较为完整清晰。实验组术后2、6、24、48 h海马组织miRNA-125b表达及脑组织Bcl-2、p53蛋白表达高于模型组,p-AKT蛋白表达低于模型组(P均<0.05)。结论腺苷预处理有助于减轻大鼠脑缺血再灌注损伤;腺苷可能是通过上调脑组织中miRNA-125b表达、下调AKT蛋白磷酸化水平、上调Bcl-2蛋白和p53蛋白表达,从而产生脑组织保护作用。

Objective To observe the intervention effect of adenosine preconditioning on cerebral ischemia-reperfusion injury in rats and to explore its related mechanism.Methods Healthy adult male SD rats were randomly divided into the sham operation group(n=60),model group(n=60),and experimental group(n=60).In the experimental group,the rats were injected intraperitoneally with adenosine injection of 2 mL once a day at 3 days before the establishment of the models,and the rats in the sham operation group and the model group were injected with normal saline of 2 mL at the same time.The improved thread occlusion method was used to make the models of middle cerebral artery embolism in the model group and the experimental group,while in the sham operation group,we only separated the middle cerebral artery without blocking the blood supply.The proportion of cerebral infarction volume was calculated at 24 h after operation,and the pathological changes of hippocampal tissues were observed,and the miRNA-125b in the brain tissues was detected by realtime fluorescence quantitative PCR at 2,6,24 and 48 h after operation.B-cell lymphoma 2(Bcl-2),phosphorylated protein kinase B(p-AKT)and p53 protein in the brain tissues were detected by Western blotting.Results The proportion of cerebral infarction volume in the model group and the experimental group was higher than that in the sham operation group,while that in the experimental group was lower than that in the model group(both P<0.05).The pathological morphology of neurons in the experimental group was significantly less than that in the model group,most of the cells survived,the cell membrane was intact,and the nucleus and nucleolus were more complete and clear.At 2,6,24 and 48 h after operation,the expression levels of Bcl-2 and p53 protein in the experimental group were higher than those in the model group,while the expression of p-AKT protein in the experimental group was lower than that in the model group(all P<0.05).Conclusion Adenosine preconditioning can alleviate cerebral ischemia-reperfusion injury in rats,and adenosine may play a protective role in brain tissues by up-regulating the expression of miRNA-125b,down-regulating the phosphorylation level of AKT protein,and up-regulating the expression levels of Bcl-2 and p53 proteins.