急性心肌缺血模型大鼠脑损伤及海马组织Bcl-2、Bax的表达

Changes of Bcl-2 and Bax expression in hippocampus and brain injury induced by acute myocardial ischemia in rats model

目的观察急性心肌缺血模型大鼠在不同时间脑损伤程度及海马组织B细胞淋巴瘤2(Bcl-2)及其家族成员Bax表达的变化。方法将60只雄性SD大鼠按照随机数字表法分为假手术组、即刻组、24 h组、3 d组、5 d组等5组,每组12只。除假手术组外,其余各组均采用冠状动脉血管结扎法复制急性心肌缺血模型。处死大鼠取材,通过光镜、透射电镜观察各组大鼠海马组织形态学和超微结构变化;采用免疫组化法检测各组大鼠海马组织Bax、Bcl-2的表达,并比较阳性计数。结果光镜下观察假手术组海马组织细胞分布清晰、排列整齐、形态完整,胞核呈蓝色,染色较为均匀;其余各组海马组织不同程度地出现细胞分布模糊、排列不齐、细胞减少、染色不均等现象,并随着时间推移呈逐渐加重的趋势。透射电镜下观察假手术组海马组织的细胞结构整体清晰完整,核糖体、线粒体以及粗面内质网等细胞器分布较好;其余各组大鼠海马组织整体结构受到不同程度的损伤,细胞膜遭到不同程度的破坏,随着时间的推移,病理改变逐渐加重。与假手术组比较,各造模组Bax阳性细胞计数明显增多,Bcl-2阳性细胞计数明显减少,差异均有统计学意义(P<0.01);与即刻组比较,24 h组、3 d组、5 d组Bax阳性细胞计数明显增多,Bcl-2阳性细胞计数明显减少,差异均有统计学意义(P<0.01);与24 h组比较,3 d组、5 d组Bax阳性细胞计数明显增多,Bcl-2阳性细胞计数明显减少,差异均有统计学意义(P<0.01)。结论急性心肌缺血模型大鼠海马组织整体结构受到不同程度的损伤,且Bax的表达随时间推移呈不断增加趋势,Bcl-2的表达随时间推移呈递减趋势。

Objective To observe the degree of brain injury and the expression of B cell lymphoma 2(Bcl-2)and family member Bax in hippocampus of acute myocardial ischemia rats model at different time points.Methods Sixty male SD rats were divided into 5 groups according to random number table,namely,sham operation group,immediate group,24 h group,3 days group and 5 days group,with 12 rats in each.Except the sham operation group,the other four groups all adopted the coronary artery ligature to replicate the acute myocardial ischemia model.Rats were sacrificed and the morphological and ultrastructural changes of their hippocampus in each group were observed by light and transmission electron microscopy.The expressions of Bax and Bcl-2 in the hippocampal tissues of rats in each group were detected by immunohistochemistry,and the positive counts were compared.Results Under the light microscope of HE staining method,the hippocampal cells in the sham operation group were clearly distributed,neatly arranged and morphologically intact,with blue nuclei and relatively uniform staining.In the other groups,the hippocampal tissues showed fuzzy cell distribution,uneven arrangement,decreased cells and uneven staining,which gradually increased with time.Under transmission electron microscopy,the hippocampal tissue structure of sham operation group was clear and complete,and the distribution of ribosomes,mitochondria and rough endoplasmic reticulum was well.The overall structure of the hippocampal tissues and the cell membranes of the other groups was damaged to varying degrees,and the pathological changes were gradually increased with the passage of time.Compared with the sham operation group,the Bax positive cell count increased significantly in each establishing model group,the Bcl-2 positive cell count significantly decreased,and the difference was statistically significant(P<0.01).Compared with the immediate group,the Bax positive cell count increased significantly in 24 h group,3 days group and 5 days group,while the Bcl-2 positive cell count decreased significantly,and the difference was statistically significant(P<0.01).Compared with 24 h group,the Bax positive cells count increased significantly in 3 days group and 5 days group,and the Bcl-2 positive cells count decreased significantly(P<0.01).Conclusion The overall hippocampal structure of rats model with acute myocardial ischemia was damaged to varying degrees,and the expression of Bax increased over time,while the expression of Bcl-2 decreased over time.