目的研究凋亡显像剂^(99)Tc^m-人膜联蛋白V(Annexin V)的制备及其与多巴胺能神经元凋亡模型的体外结合特性。方法运用双功能螯合剂联肼尼克酰胺(HYNIC)进行^(99)Tc^m 标记 Annexin V,形成^(99)Tc^m-HYNIC-Annexin V,经 Sephadex G-25柱层析分离纯化,采用快速薄层层析(ITLC)法检测放化纯。将^(99)Tc^m-HYNIC-Annexin V 与经过1-甲基-4-苯基吡啶离子(MPP^+)处理制模的大鼠肾上腺嗜铬细胞瘤PC12细胞进行体外细胞量及时间-温度结合实验、饱和结合实验和竞争结合实验.得到^(99)Tc^m-HYNIC-Annexin V 与多巴胺能神经元凋亡模型的结合特性,并比较其与正常细胞及不同凋亡水平下细胞模型的结合特性。结果①^(99)Tc^m-YNIC—Annexin V 标记率(64.56±6.23)%,比活度(3.7～74)×10~5kBq/mg,放化纯(93.6±2.48)%,室温放置4 h 后放化纯仍大于90%。②^(99)Tc^m-HYNIC-Annexin V 与多巴胺能神经元凋亡模型的结合具有特异性、可饱和性,Scatchard 图示平衡解离常数(K_d)为(7.16±1.78)nmol/L,最大结合容量(B_(max))为(178.73±32.62)fmol/10~6细胞。结论多巴胺能神经元凋亡模型对^(99)Tc^m-HYNIC-Annexin V 有良好的摄取,可进一步行动物体内研究。
Objective：To investigate the apoptosis of dopaminergic neurons and the protective effect of nicotine in 1-methyl-4-phenyl- 1, 2,3,6-tetrahydropyridine （MPTP）-induced mouse model of Parkinson＇s disease. Methods：The mouse model of Parkinson＇s disease were formed by MPTP （30 mg/kg/d×7, i.p. ）; and the loss and apoptosis of dopaminergic neurons was observed by Tyrosine Hydroxylase（TH） and TUNEL stains.In ＂Nicotime plus MPTP＂ group, mice were pretreated with nicotine before MPTP injection. The putative protective effect of nicotine was analyzed. Results：The number of TH-positive cells decreased during MPTP treatment. Apoptotic neurons began to appear after three injections of MPTP and peaked on the 8th day. In the MPTP-intoxicated mice treated with nicotine, the loss of TH-positive cells was significantly less than that of MPTP- treated group （30 mg/kg/d×7）（P 〈 0.05）. Conclusion：The chronic treatment of MPTP can induce the apoptosis of dopaminergic neurons in substantia nigra, and nicotine might have a neuroprotecitve effect on dopaminergic neurons against MPTP toxicity.
