Lactacystin诱导的帕金森病大鼠模型病理退行性改变的研究

目的 观察Lactacystin诱导的帕金森病(PD)模型大鼠的病理退行性改变,探索其发病机制.方法 取成年健康SD大鼠32只,采用随机数字表法分为实验组(16只)和对照组(16只),实验组左侧黑质致密部(SNc)注射蛋白酶体抑制剂Lactacystin,对照组以等体积生理盐水代替.分别存注射后1、3、5、7、9、11、14和21 d,观察两组大鼠的行为学变化;应用HE染色观察小胶质细胞并计数,免疫组化检测黑质及纹状体组织罗暗算酪氨酸羟化酶(TH)神经元变化和RT-PCR检测黑质部TH和α-synuclein mRNA的表达.结果 与对照组相比,实验组大鼠逐渐出现行为学改变:HE染色显示小胶质细胞在注射Lactacystin后第1天为(3501.92±57.32)个,第7天为(4895.50±52.67)个,第21天为(5340.18±52.87)个,与对照组(3271.23±63.76)个相比增高,差异具有统计学意义(P＜0.05):免疫组化检测显示黑质中多巴胺(DA)神经元在注射Lactacystin后逐渐变性死亡,第7天神经元数为(568.57±36.39)个,第21天为(119.67±21.06)个,与对照组(679.76±30.24)个相比,差异具有统计学意义(P＜0.05);免疫组化检测纹状体TH免疫阳性纤维显示其在注射Lactacystin后逐渐稀疏,强度逐渐变弱,实验组TH免疫阳性纤维平均光密度第7天为(0.1953±0.0076),与对照组(0.2412±0.0067)相比,差异无统计学意义(P＞0.05),第21天为(0.0781±0.0013)个,与对照组(0.2412±0.0067)个相比降低,差异具有统计学意义(P＜0.05).同时,实验组mRNA检测显示,THmRNA表达越来越少,而α-synuclein mRNA在残存TH神经元中逐渐增多.结论 Lactacystin诱导的PD模型大鼠的病理呈退行性改变.符合PD发病的隐匿性、缓慢进展性特征.

Lactacystin-induced pathologically regressive changes of rat models of Parkinson's disease

Objective To observe the pathologically regressive changes of rat models of Parkinson's disease (PD) induced by Lactacystin (Lac), and to investigate the pathogenesis of PD.Methods Totally 32 SD rats were randomly divided into 2 groups: test group and control group. Lac, a selective proteasome inhibitor, was unilaterally injected stereotaxically into the left substantia nigral pars compacta (SNc) of rats. Equal volume of saline was injected in control group. On day 1, 3, 5, 7, 9, 11, 14 and 21 post-in jection, we observed the behavioral changes of the rats and pathological changes in substantial nigra and striatum, and detected the expressions of tyrosine hydroxylase (TH) and α-synuclein by immunohistochemistry (IHC) and HE staining and the expressions of their mRNA by RT-PCR. Results Behavioral changes were found in the rats of test group. By HE staining, after Lac-treatment, microglia was increased on the 1st day (3501.92±57.32), 4895.50±52.67 on day 7, 5340.18±52.87 on day 21 (P<0.05 vs control group 3271.23±63.76). By IHC, after Lac-treatment, the test group manifested retrograde dopaminergic neuron degeneration in nigra; the number of neurons was 568.57±36.39 on day7 and 119.67±21.06 on day 21 (P<0.05 vs control group 679.76±30.24). By IHC, after Lac-treatment,expression of TH-positive nerve fiber in left striatum was decreased on day 7, being 0.1953±0.0076 (P>0.05 vs control group 0.2412±0.0067); it was 0.0781±0.0013 on day 21, significantly different from control group 0.2412±0.0067 (P<0.05). Meanwhile, in the test group, the detection of mRNA expression displayed that TH neurons were reduced, while α-synuclein mRNA was accumulating in survival TH neurons. Conclusion Pathological changes in PD models induced by lactacystin are retrograde along with time going on, and consistent with the characters of delitescence and slow progressions in PD.