缺氧缺血性脑损伤大鼠脑组织海马区p-tau蛋白与凋亡相关蛋白Bcl-2、Bax的关系

The connection among the expression of p-tau protein and apoptosis related proteins Bcl-2 and Bax in the hippocampus of hypoxic-ischemic neonatal rats

目的观察缺氧缺血性脑损伤(HIBD)大鼠脑组织海马区磷酸化tau(p-tau)蛋白及凋亡相关蛋白Bcl-2、Bax的表达,并分析其相关性。方法选择新生SD大鼠56只,随机分为正常对照组8只、假手术组8只和HIBD组40只(按处死时间点分为3、6、12、24、48 h 5个亚组,每组8只)。HIBD组参照Rice法建模,并在不同时间点断头取脑。假手术组仅暴露左颈总动脉,正常对照组未做处理,均于手术结束后断头取脑。采用HE染色法观察各组脑组织海马区细胞形态结构改变,免疫组化染色法观察各组脑组织海马区p-tau、Bcl-2、Bax蛋白阳性细胞表达。结果正常对照组及假手术组脑组织细胞形态结构正常,基本无损伤性改变。HIBD组在HIBD后3 h细胞无明显变化;HIBD后6 h出现细胞肿胀,结构排列紊乱;HIBD后24 h细胞肿胀明显,细胞核固缩、碎裂;HIBD后48 h细胞内出现凋亡小体,神经细胞数量锐减。HIBD组各时间点脑组织海马区p-tau、Bcl-2、Bax蛋白阳性细胞数均较正常对照组和假手术组显著增多(P均<0.05);HIBD后12 h内,脑组织海马区p-tau蛋白阳性细胞数与Bcl-2、Bax蛋白阳性细胞数均呈正相关(P均<0.05)。结论 HIBD后脑组织海马区细胞启动了凋亡程序,p-tau蛋白参与了海马区细胞的凋亡过程,并且与Bcl-2、Bax蛋白的表达存在相关性。

Objective To observe the expression of phosphorylated tau （ p-tau） protein, and apoptosis related pro-teins Bcl-2 and Bax, and explore their correlations .Methods Seven-day-old newborn clean Sprague Dawley （ SD） rats, were randomly divided into normal control group （8 cases）, sham operation （8 cases）, and HIBD group （which was divid-ed into by death time points 3, 6, 12, 24, 48 h subsection 8 cases in each group）.HIBD animal model was established by Rice method, and took the brain at different time points .In sham group, rats were just exposed the left carotid artery , and in the control group rats did not dispose .Rats were all decapitated brain immediately at the end of surgery .Hematoxylin-e-osin （ HE） staining was used to view morphological changes in the hippocampus , and immunohistochemical staining was used to test the expressions of p-tau, Bcl-2 and Bax protein.Results Brain tissues in the normal control group and sham operation group was normal .In HIBD group, the cell has not significant change 3 h after HIBD;Cell swelling and structur-al disorder 6 h after HIBD; Cell swelling significantly , nuclear condensation , fragmentation 24 h after HIBD;48 h after HIBD, apoptotic bodies occured , the number of nerve cells was dropped .In HIBD group, Bcl-2 and Bax positive cells in HIBD group at each time point were more than those in the normal control group and the sham group （all P〈0.05）;In the hippocampus of HIBD group , p-tau positive cells was positively correlated with Bcl-2 and Bax positive cells during 12 h af-ter HIBD（P〈0.05）.Conclusion The hippocampus neurolcytes actiwated apotosis mechanism afer HIBD early period . P-tau protein was involved in neuronal apoptosis after HIBD , and there is connection among p-tau, Bcl-2 and Bax protein.