组蛋白去乙酰化酶1和胶质细胞源性神经生长因子在老龄小鼠LPS-PD模型中的表达特点

The Expression of Sirtuin1 and Glial Cell Line-derived Neurotrophic Factor in LPS-PD Aged Mice Model Aging Associated Mice LPS-PD Model

目的观察老龄和脂多糖(LPS)刺激二次打击致小鼠PD模型脑组织中组蛋白去乙酰化酶1(Sir T1)和胶质细胞源性神经生长因子(GDNF)的表达水平。方法 C57BL/6小鼠随机分为老年LPS-PD组(n=8)、青年LPS-PD组(n=8)、老年对照组(n=8)、青年对照组(n=8)。PD模型制作:LPS 20μL(1μg·μL^(-1)),两侧鼻孔滴入,隔日1次,共60 d。对照组用等量生理盐水滴鼻。采用动物行为学爬竿实验测定小鼠行为变化。Western blot检测小鼠脑组织中酪氨酸羟化酶(TH)、Sir T1和GDNF表达,免疫组织荧光法检测黑质纹状体区TH表达,分析老龄和LPS刺激作用下多巴胺神经元丢失与Sir T1、GDNF表达量的变化。结果与青年对照组比较,老年LPS-PD组爬竿实验时间延长最为显著,TH、GDNF和SirT1表达下降最为显著(P<0.01);老年对照组和青年LPS-PD组运动时间显著延长,TH、SirT1表达显著下降(P<0.05),Sir T1表达与TH表达呈正相关性。青年LPS-PD组GDNF表达显著高于青年对照组(P<0.05)。老龄和LPS二次打击作用均可导致多巴胺神经元显著丢失,运动协调能力下降。脑内GDNF和SirT1表达量随年龄增长而下降,与多巴胺神经元丢失相平行;但青年LPS-PD组GDNF呈代偿性高表达。结论老龄和LPS二次打击下PD模型多巴胺神经元的丢失可能与GDNF和Sir T1神经保护因子表达下降有一定相关性。

Aim To investigate the expression of sirtuin1 and glial cell line-derived neurotrophic factor（GDNF） in Parkinson＇s disease（PD） of young and aged mice induced with lipopolysaccharide（LPS）. Methods C57BL/6 mice were randomly divided into a aged control group（n=8）, a young control group（n=8）, a aged LPS-PD group（n=8）, and a young LPS-PD group（n=8）. PD model were induced with a bilateral intranasal instillation of LPS or normal saline every other day for 2 months. Behavior activity was detected using pole test. The expression of TH, Sir T1 and GDNF were detected by Western blot and immunofluorescence. Results Pole test time was significantly prolonged, and the expression of TH, Sir T1 and GDNF was significantly reduced in the aged LPS-PD group compared to the young control group（P〈0.01）. The expression of TH or Sir T1 and pole test time showed a negative correlation in all groups except the young LPS-PD group（P〈0.05）. However, the expression of GDNF was significantly increased in young LPS-PD group compared to the young control group（P〈0.05）. The loss of dopamine（DA） neurons was also accompanied with the declined expression of the Sir T1 and GDNF under the dual effects of age and LPS. Conclusion The loss of DA neurons in subtantia nigra of PD model might be associated with the decrease of Sir T1 and GDNF under double hit of age and LPS.