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目的:研究过度表达Bc-l2的大鼠全脑缺血再灌注后P53在海马回的表达,探讨Bc-l2的抗凋亡作用及机制。方法:雄性健康SD大鼠随机分为3组(n=30)。缺血再灌注组(IR组),采用4-血管法建立全脑缺血再灌注模型,6 min缺血后给予再灌注;假手术组(SO组),只暴露血管而不夹闭;Bc-l2过度表达组(Bc-l2组),Bc-l2过度表达大鼠模型造模成功后处理同IR组。所有动物于6、12、24、48、72及96 h行4%多聚甲醛灌注处理,将脑组织切片行免疫组化染色、原位末端标记法和HE染色,光镜下观察P53在海马回CA1和CA3区的表达、神经元形态及结构的变化以及凋亡神经细胞数,结果行统计学分析。结果:①全脑缺血再灌注后24 h,IR组CA1区P53蛋白开始表达,程度较弱,随后逐渐增加,于72 h达高峰后下降,主要位于胞核;CA3区于再灌注后48 h才出现P53蛋白的表达,72 h达高峰,但表达强度较CA1区弱(P<0.05)。Bc-l2组CA1和CA3区P53蛋白表达强度均弱于IR组(P<0.05),主要位于胞浆。②HE染色:全脑缺血再灌注后72 h,IR组CA1区有明显组织水肿,神经元数目降低,排列紊乱,核膜不清晰,未见核仁;CA3区神经元损伤程度较CA1区轻(P<0.05);Bc-l 2组神经元损伤较IR组轻(P<0.05)。③原位末端标记法染色:与SO组比较,IR组海马CA1区全脑缺血再灌注后24~48 h凋亡细胞数最多(P<0.01),再灌注后72 h海马CA1区凋亡细胞数开始减少;与IR组比较,Bc-l2组凋亡细胞均较少(P<0.05)。结论:Bc-l2过度表达可抑制大鼠全脑缺血再灌注后P53在海马回的表达。
OBJECTIVE: To investigate the expression of P53 in hippocampus after global cerebral ischemia-reperfusion in rats overexpressing Bc-12 and to explore the anti-apoptotic effect and mechanism of Bc-l2. Methods: Male healthy SD rats were randomly divided into 3 groups (n = 30). Ischemia-reperfusion group (IR group), the model of global cerebral ischemia-reperfusion was established by 4-vessel method and reperfusion was performed 6 min after ischemia. The sham-operated group (SO group) -l2 overexpression group (Bc-l2 group), Bc-l2 overexpression rat model successfully treated with the IR group. All animals were subjected to 4% paraformaldehyde perfusion at 6, 12, 24, 48, 72 and 96 h. Immunohistochemistry, HE staining and immunohistochemical staining of brain tissue sections were performed. The expression of P53 in the hippocampus Back to CA1 and CA3 area expression, neuronal morphology and structure changes and the number of apoptotic nerve cells, the results of statistical analysis. Results: ①The expression of P53 protein in CA1 region of IR group began to decline at 24 h after ischemia-reperfusion, and then gradually increased. It reached peak at 72 h and decreased mainly in the nucleus. In CA3 area, The expression of P53 protein appeared at 72 h, but peaked at 72 h, but its expression intensity was weaker than that of CA1 (P <0.05). The expression of P53 protein in CA1 and CA3 of Bc-l2 group was weaker than that in IR group (P <0.05), mainly in the cytoplasm. ②HE staining: At 72 h after ischemia-reperfusion, there was obvious edema in CA1 area of IR group, the number of neurons decreased, disordered arrangement, unclear nuclear membrane and no nucleoli. The degree of neuron damage in CA3 area was lighter than that in CA1 area (P <0.05). The damage of neurons in Bc-1 2 group was lighter than that in IR group (P <0.05). ③ In situ end-labeling staining: compared with the SO group, the number of apoptotic cells in the hippocampal CA1 subfields was the highest at 24-48 h after reperfusion (P <0.01), and the apoptosis of hippocampal CA1 subfields at 72 h after reperfusion The number of cells began to decrease. Compared with IR group, apoptotic cells in Bc-l2 group were less (P <0.05). Conclusion: Overexpression of Bc-l2 can inhibit the expression of P53 in hippocampus after global cerebral ischemia and reperfusion in rats.