Vis J C, Verbeek M M, de Waal R M, ten Donkelaar H J, Kremer B
Departments of Neurology and Pathology, University Hospital Nijmegen, Nijmegen, The Netherlands.
Neuropathol Appl Neurobiol. 2001 Feb;27(1):68-76. doi: 10.1046/j.0305-1846.2001.00305.x.
The mitochondrial toxin 3-nitropropionic acid (3-NP) causes selective striatal lesions in rats and serves as an experimental model for the neurodegenerative disorder Huntington's disease (HD). Apoptotic cell death has been implicated for the neuronal degeneration that occurs in HD brains. The present study was designed to investigate whether the 3-NP-induced cell death in rats involves apoptosis and an altered expression of Bcl-2 family proteins. Systemic administration of 3-NP via subcutaneous Alzet pumps resulted in lesions of variable severity with neuronal loss and gliosis in the striatum. Using the terminal transferase-mediated biotinylated-UTP nick end-labelling (TUNEL) of DNA, TUNEL-positive cells exhibiting typical apoptotic morphology were detected only in the striatum of rats with a severe lesion. Furthermore, the neuronal expression of the pro-apoptotic protein Bax was strongly increased in the core of the severe lesion. Expression of the anti-apoptotic marker Bcl-2 was unchanged in this location, but was enhanced in the margins of the lesions. A moderately increased expression of both Bax and Bcl-2 was observed in dark neurones in the mild lesion and in the subtle lesion. The presence of nuclear DNA fragmentation, strong granular Bax expression and an increased Bax/Bcl-2 ratio in the centre of severe lesions suggests the occurrence of apoptotic cell death following 3-NP administration. In contrast, the dark compromised neurones observed in 3-NP-treated animals revealed an equally enhanced expression of both Bax and Bcl-2, but lacked TUNEL-labelling, and are therefore not apoptotic.
线粒体毒素3-硝基丙酸（3-NP）可导致大鼠纹状体选择性损伤，是神经退行性疾病亨廷顿舞蹈病（HD）的实验模型。凋亡性细胞死亡被认为与HD大脑中发生的神经元变性有关。本研究旨在调查3-NP诱导的大鼠细胞死亡是否涉及凋亡以及Bcl-2家族蛋白表达的改变。通过皮下植入Alzet泵全身给予3-NP导致不同严重程度的损伤，伴有纹状体神经元丢失和胶质细胞增生。使用DNA末端转移酶介导的生物素化UTP缺口末端标记（TUNEL），仅在严重损伤大鼠的纹状体中检测到呈现典型凋亡形态的TUNEL阳性细胞。此外，促凋亡蛋白Bax在严重损伤核心区域的神经元表达强烈增加。抗凋亡标志物Bcl-2在该区域的表达未改变，但在损伤边缘增强。在轻度损伤和轻微损伤的深色神经元中观察到Bax和Bcl-2的表达均适度增加。严重损伤中心存在核DNA片段化、强烈的颗粒状Bax表达以及增加的Bax/Bcl-2比值，表明给予3-NP后发生了凋亡性细胞死亡。相比之下，在3-NP处理的动物中观察到的深色受损神经元显示Bax和Bcl-2的表达均同样增强，但缺乏TUNEL标记，因此不是凋亡细胞。
