积雪草酸对MPTP诱导小鼠帕金森样运动症状的影响

Effects of asiatic acid on MPTP-induced Parkinson's disease-like motor symptoms in mice

目的考察积雪草酸(AA)对1-甲基-4-苯基-1,2,3,6-四氢吡啶(MPTP)诱导小鼠帕金森(PD)样运动症状的影响及其神经保护机制。方法取雄性C57BL/6小鼠45只,除对照组9只小鼠外,其余用25 mg/kg MPTP腹腔注射7 d建立帕金森病模型,随机分为模型组,积雪草酸低、高剂量组,阳性对照组。造模同时开始连续11 d灌胃给予相应药物或溶剂(0.5%羧甲基纤维素钠),第12天进行行为学测试。ELISA试剂盒检测血清白介素-1β(IL-1β)、肿瘤坏死因子-α(TNF-α)水平;免疫组织化学法检测黑质酪氨酸羟化酶(TH)阳性细胞;检测中脑IL-1β、TNF-α、诱导型一氧化氮合酶(i NOS)、环氧化酶-2(COX-2)的mRNA表达,以及丙二醛(MDA)含有量。结果与模型组相比,给予积雪草酸的小鼠在行为学测试中表现更好(P<0.05,P<0.01)。而且,积雪草酸通过上调TH表达、增加TH阳性细胞数量来有效保护黑质多巴胺能神经元(P<0.05);抑制中脑i NOS、COX-2、IL-1β、TNF-α的mRNA表达(P<0.05,P<0.01);降低中脑MDA水平(P<0.01);降低血清IL-1β、TNF-α含有量(P<0.05,P<0.01)。结论积雪草酸能缓解PD小鼠运动障碍和多巴胺能神经元损伤,抗炎、抗氧化是其可能的神经保护机制。

AIM To investigate the effects of asiatic acid （AA） on 1-methyl-4-phenyl-1, 2, 3, 6-tetrahy- dropyridine （MPTP） -induced Parkinson＇s disease （PD） -like motor symptoms in mice and its neuroprotective mechanism. METHODS Forty-five male C57BL/6 mice, except the nine mice in control group, were induced to be the PD models by peritoneal injection of 25 mg/kg MPTP for seven days and then were randomly assigned to model group, low-dose, high-dose AA groups and positive control group. Both the control group and the model group were administered with 0. 5% sodium carboxyl methyl cellulose （CMC-Na） solution, the AA groups were dosed with 12. 5 mg/kg and 25 mg/kg AA, respectively, and the positive control group was given 75 mg/kg daily intragastric gavage of levodopa for eleven days. On the twelfth day, behavioral tests were performed. Tyrosine hydroxylase （TH） positive cells in substantia nigra were detected by immunohistoehemistry. The mRNA expres-sions of iNOS, COX-2, TNF-α, IL-1β, and malonaldehyde （MDA） content in midbrain were measured. The levels of IL-1β and TNF-α in the serum were detected using ELISA kits. RESULTS The mice treated with asiatic acid performed better in behavior tests than those in the model group （P 〈 0.05, P 〈 0. 01 ）. In addition, asiatic acid effectively protected the dopaminergic neurons in the substantia nigra due to upregulated TH expression and in- creased number of TH positive cells （P 〈 0.05 ）. The asiatic acid-treated mice had their mRNA expressions of IL-1β, TNF-α, iNOS and COX-2 in midbrain markedly suppressed （P 〈0. 05, P 〈0. 01 ）, and a significant MDA level decrease in the midbrain tissue as well （P 〈 0.01 ）. Furthermore, reductions of IL-1β and TNF-α contents in the serum were observed （P 〈 0. 05, P 〈 0. 01 ）. CONCLUSION Asiatic acid attenuates motor dysfunction and dopaminergic neuronal deficits in PD mice, and the neuroprotective mechanisms may attribute to its anti-oxidative and anti-inflammatory activities.