3-硝基丙酸预处理阻止黑质多巴胺神经元细胞凋亡

3-nitropropionic Acid Preconditioning Prevents Apoptosis of Dopaminergic Neurons in Substanial Nigra in Rats

目的:观察3 硝基丙酸(3 NP)预处理时黑质多巴胺(DA)神经元细胞凋亡改变的作用机制及5 羟癸 酸(5 HD)对3 NP效果的影响。方法:25只雄性SD大鼠随机分为5组各5只。右侧黑质内立体定向注射6 羟多 巴胺(6 OHDA)建立帕金森病(PD)模型组,对照组大鼠立体定向和腹腔注射生理盐水,3 NP组在对照组的基础上 腹腔注射3 NP(20mg/kg),预处理组(CPC组)造模前24h给予3 NP(20mg/kg),5 HD组于造模前10min侧脑 室内给予5 HD(5mg/kg)。采用缺口末端标记原位检测法及免疫组化法检测黑质DA神经元细胞凋亡率及酪氨 酸羟化酶(TH)阳性细胞数。结果:PD组、CPC组及5 HD组与对照组和3 NP组比较细胞凋亡率均明显增高,损 毁侧TH阳性细胞数显著降低(P<0.01或P<0.05);CPC组与PD组比较细胞凋亡率降低,TH阳性细胞数增多 (P<0.05);5 HD组与PD组比较则差异无显著性意义(P>0.05)。结论:3 NP预处理可抑制细胞凋亡,而5 HD 可阻断3 NP预处理保护效应。线粒体ATP敏感性钾通道激活参与3 NP预处理神经元保护作用。

Objective: To observe the mechanism of 3-nitropropionic acid (3-NP) preconditioning on the dopaminergic (DA) neurons apoptosis in substantial nigra (SN) and the effects of 5-hydroxydecanoate (5-HD) on 3-NP preconditioning. Methods:25 adult male SD rats were randomly divided into five groups(n=5). The PD models (PD group) were established after unilateral stereoscopically microinjection of 6-OHDA into the right side substantial nigra pars compacta (SNpc).The rats in the control group were treated with 0.9% saline by stereoscopic and intraperitoneal (ip) injection. Those in the 3-NP group were administered with 3-NP (20 mg/kg, ip) based on the control group. Those in the preconditioning (CPC) group received 3-NP (20 mg/kg,ip) 24 h before PD development. In the 5-HD group, rats were treated with 3-NP on the basis of given 5-HD (5mg/kg). The percentage of apoptosis and the number of tyrosine hydroxylase (TH)-positive neurons in the SN were determined by using TUNEL method and TH immunohistochemical staining respectively. Results: Compared with the control group or the 3-NP group, the percentage of apoptosis among SN dopaminergic neurons on the 6-OHDA-lesioned side was increased,whereas the number of TH-positive staining cells decreased obviously in the PD group, the CPC group, and the 5-HD group (P<0.01 or P<0.05). However, there was an increase in the number of TH-positive staining cells and a decrease in the percentage of apoptosis in the CPC group as compared with the PD group (P<0.05). There was no statistically significant difference in the levels of apoptosis and TH-positive staining cell in SN between the CPC group and the PD group. Conclusions: 3-NP preconditioning can prevent apoptosis, which can be blocked by 5-HD. And the activation of mtKATP channels might mediate the neuroprotective effects during chemical preconditioning with 3-NP.