论文部分内容阅读
目的研究不同时程的亚低温治疗对大鼠大脑中动脉闭塞(MCAO)模型的神经元细胞凋亡及Bcl-2,Bax基因表达的影响。方法健康雄性SD大鼠共40只,月龄两三个月。按抽签法随机分为5组,每组8只(n=8),分别为:假手术组(A)、对照组(B)、亚低温0.5h组(C)、亚低温1.0h组(D)、亚低温3.0h组(E)。采用Longa线栓法制作MCAO模型,缺血3.0h后再灌注。缺血后即刻分别进行不同时程(0.5,1.0,3.0h)的亚低温治疗,再灌注后24h断头取脑,连续切片作TUNEL染色及Bcl-2,Bax免疫组化染色。结果凋亡神经元细胞(TUNEL阳性细胞)主要见于梗死灶周围的纹状体及额顶部皮层。Bcl-2及Bax阳性细胞也主要见于梗死灶周围的纹状体及额顶部皮层,与该区凋亡细胞的集中分布相一致。与对照组的Bcl-2细胞阳性率相比,亚低温3.0h组增加犤(23.0±3.8)%,P<0.05)犦;与对照组的Bax细胞阳性率相比,亚低温1.0,3.0h组均降低犤分别为(45.9±4.1)%,(32.4±3.7)%,P<0.05,P<0.01犦;凋亡细胞阳性率与Bcl-2/Bax的比值呈负相关关系(r=-0.9759,P<0.01)。结论亚低温1.0h以上有抑制细胞凋亡作用;Bcl-2/Bax的比值能影响细胞凋亡的发生。
Objective To investigate the effects of hypothermia at different time courses on the neuronal apoptosis and the expression of Bcl-2 and Bax in rat model of middle cerebral artery occlusion (MCAO). Methods A total of 40 healthy male SD rats, two months and three months of age. The patients were randomly divided into five groups according to the random sampling method, n = 8 in each group: sham operation group (A), control group (B), hypothermia 0.5h group (C), hypothermia 1.0h group D), mild hypothermia 3.0h group (E). The MCAO model was made by Longa suture method and was reperfused after 3.0h of ischemia. Mild hypothermia treatment was performed at different time points immediately after ischemia (0.5, 1.0, 3.0 h). Brain was decapitated 24 h after reperfusion. TUNEL and Bcl-2, Bax immunohistochemical staining were performed on serial sections. Results Apoptotic neuronal cells (TUNEL positive cells) mainly found in the striatum and frontal cortex around the infarct. Bcl-2 and Bax-positive cells are also mainly seen in the striatum and frontal cortex around the infarct, which is consistent with the concentration distribution of apoptotic cells in this area. Compared with the positive rate of Bcl-2 cells in the control group, the mild hypothermia increased in the 3.0h group (23.0 ± 3.8%, P <0.05); compared with the positive rate of the Bax cells in the control group, (45.9 ± 4.1)%, (32.4 ± 3.7)% respectively, P <0.05, P <0.01 犦. There was a negative correlation between the positive rate of apoptotic cells and the ratio of Bcl-2 / Bax (r = 0.9759, P <0.01). Conclusion Mild hypothermia over 1.0h can inhibit cell apoptosis. The ratio of Bcl-2 / Bax can affect apoptosis.