【摘要】 为了研究大鼠颈部淋巴引流阻断后海马内Bcl-2、Bax的表达和超微结构的变化,本研究采用结扎颈部淋巴管并摘除浅、深淋巴结的方法制作大鼠淋巴滞留性脑病模型,并分别于术后1、2、3、5、7和14d处死动物。透射电子显微镜观察海马脑组织的超微结构变化,Western blotting方法检测海马内Bcl-2和Bax蛋白的表达。结果显示:(1)电镜下可见海马组织有水肿的结构变化,血管周围出现半月形间隙,毛细血管受压变形;还可观察到有些神经细胞出现凋亡,细胞皱缩变小,轮廓不清晰,核皱缩变形,核染色质边集,细胞质电子密度增高。以上变化于术后第2d出现,第5d最明显,14d时恢复至正常水平。(2)Western blotting技术在海马内检测到Bax蛋白的表达明显高于对照组,于术后2d开始增高,3d达最高值,7d恢复至正常水平,2、3和5d时均高于对照组(P<0.01);但未在海马内检测到Bcl-2蛋白的表达。本文结果提示:阻断颈部淋巴引流可导致海马出现脑水肿的超微结构变化,并出现神经细胞的凋亡,故推测海马神经细胞的凋亡与Bax的表达增加有关。更多还原

【Abstract】 To investigate Bcl-2 and Bax expression and ultrastructural changes in the hippocampus after blockade of cervical lymphatic draining of rats, the model of lymphostatic encephalopathy was established by occluding lymphatic vessels and removing both the shallow and deep cervical lymph nodes of rats in the present study. The animals were sacrificed at 1, 2, 3, 5, 7 and 14 days after operation. The ultrastructural changes of the hippocampus were observed by electron microscope. The expression of Bcl-2 and Bax in the hippocampus was examined by the Western blotting method. The present results showed that (1) The structural changes of edema of hippocampus were observed under electron microscope, the perivascular spaces were enlarged and full of fluid, the capillaries were pressed into distortion. Some neurons showed apoptotic conformation: the cell shrinked and the nuclear distorted, the chromatin assembled into conglomeration along the nuclear membrane and the plasm had high electron density. The phenomena mentioned above appeared at 2 days, were most obvious at 5 days and recovered to control level at 14 days; (2) Western blotting detected that the protein expression of Bax began to increase at 2 days, arrived maximum at 3 days and recovered to control level at 7 days in the hippocampus. Bax protein expression at 2, 3 and 5 days was obviously higher compared with normal rats (P<0.01). But the protein expression of Bcl-2 could not be detected by Western blotting. The results suggested that blockage of cervical lymphatic draining could lead to ultrastractural changes of brain edema in the hippocampus and neuronal apoptosis in this model. Therefore, it is maybe involved that the neuronal apoptosis in the hippocampus had relationships with the increasing expression of Bax.更多还原