番荔枝酰胺衍生物FLZ对肠道功能和多巴胺神经元的保护作用

Protective effect of squamosamide derivative FLZ on intestinal function and dopaminergic neurons

目的:研究番荔枝酰胺衍生物FLZ对小鼠结肠功能及多巴胺神经元的保护作用和机制。方法:在1-甲基-4-苯基^(-1),2,3,6-四氢吡啶(MPTP)联合丙磺舒(MPTP/p)诱导的慢性帕金森病(PD)小鼠模型中,FLZ 75 mg·kg^(-1)灌胃(ig)给药8周。测量小鼠的排便频率、排便总量和粪便干重,并进行转棍和爬杆测试;采用免疫组化测定中脑黑质酪氨酸羟化酶(TH)阳性神经元的数量;采用Western Blot检测小鼠结肠和中脑TH、诱导型一氧化氮合酶(i NOS)、环氧化酶-2(COX-2)的表达,结肠中磷脂酰肌醇-3激酶(PI3K)、磷酸化磷脂酰肌醇-3激酶(p-PI3K)、蛋白激酶B(Akt)和磷酸化蛋白激酶B(p-Akt)的表达。结果:FLZ 75 mg·kg^(-1)显著改善慢性PD模型小鼠结肠收缩功能障碍,提高结肠TH的表达,抑制结肠i NOS,COX-2的表达。FLZ显著提高中枢多巴胺能神经元的功能,表现为小鼠转棍测试潜伏期延长和爬杆测试评分增加,中脑TH的数量和表达增加,中脑i NOS,COX-2的表达减少。FLZ抑制结肠PI3K/Akt炎症信号通路的激活。结论:FLZ可能通过PI3K/Akt信号通路抑制结肠炎症,进而通过肠脑轴而减轻中枢炎症反应,保护多巴胺能神经元,改善PD小鼠运动功能障碍。

Objective:To investigate the protective effect of a natural squamosamide derivative FLZ on intestinal function and dopaminergic neurons.Methods:Chronic PD model was induced by injection of 25 mg·kg-1 MPTP(sc)and 250 mg·kg-1 probenecid(ip)in mice 10 times with an interval of 3.5 days.After that,FLZ 75 mg·kg-1 was administered for 8 weeks.The frequency of fecal output,total fecal pellets and dry weight ratio in stool were detected.Rotarod and the pole tests were conducted to reflect motor behavior of mice.The number of tyrosine hydroxylase(TH)-positive neurons in the substantia nigra was determined by immunohistochemistry.The expression of TH,inducible nitric oxide synthase(i NOS),cyclooxygenase-2(COX-2),phosphoinositide 3-kinase(PI3 K),phospho-PI3 K(p-PI3 K),protein kinase B(Akt)and p-Akt(phospho-Akt)was determined by Western blot.Results:FLZ significantly improved gastrointestinal dysfunction,increased the expression of TH in the colon,and attenuated colon inflammation by inhibiting i NOS and COX-2 expression in MPTP/p-induced chronic PD mouse model.Besides,FLZ significantly improved the function of central dopaminergic neurons,as indicated by theincrease of latency of the rod test,the score of the climbing test,the number and the expression of TH in the midbrain,and by the decreased expression of i NOS and COX-2 in the midbrain.The mechanical study demonstrated that FLZ inhibited the activation of PI3 K/Akt inflammatory signaling pathway.Conclusions:FLZ inhibited colonic inflammation through the PI3 K/Akt signaling pathway,thereby might attenuate central inflammatory responses through the gut-brain axis,and thus protected dopaminergic neurons,and improved dyskinesia in PD mice.