U99194A对睡眠剥夺小鼠认知功能及海马肥大细胞活化的影响

Effects of U99194A on cognitive function and hippocampal mast cell activation in sleep‑deprived mice

目的研究多巴胺受体3(dopamine receptor three,D3R)拮抗剂U99194A对睡眠剥夺(sleep deprivation,SD)小鼠认知功能及海马肥大细胞活化的影响。方法将42只雄性C57BL/6小鼠采用随机数字表法分为3组(每组14只):对照组(Ctrl组)、睡眠剥夺组(SD组)及睡眠剥夺+U99194A组(U组)。SD组、U组小鼠采用多平台水环境法进行3 d的SD,U组行SD同时每日腹腔注射20 mg/kg U99194A连续3 d,Ctrl组与SD组腹腔注射等量的生理盐水。采用水迷宫检测小鼠认知功能,免疫组织化学法观察海马肥大细胞类胰蛋白酶表达水平,ELISA法测定海马组织IL-6、TNF-α及IL-1β含量。结果3组小鼠SD前连续5 d定位航行训练逃避潜伏期差异无统计学意义(P>0.05)。SD组及U组小鼠目标象限(第三象限)空间探索轨迹比Ctrl组局限;U组目标象限探索轨迹比SD组增加。与Ctrl组比较,SD组与U组小鼠逃避潜伏期延长,穿越隐藏平台次数减少,目标象限停留时间缩短;小鼠海马组织类胰蛋白酶平均光密度(D)值增加;海马组织IL-1β、IL-6及TNF-α含量增加(P<0.05)。与SD组比较,U组小鼠逃避潜伏期缩短,穿越隐藏平台次数增加,目标象限停留时间延长;小鼠海马组织类胰蛋白酶平均D值降低;海马组织IL-1β、IL-6及TNF-α含量下降(P<0.05)。结论U99194A改善SD小鼠认知功能可能与抑制肥大细胞活化从而抑制神经炎症有关。

Objective To investigate the effects of U99194A,a dopamine receptor 3(D3R)antagonist on cognitive function and activation of hippocampal mast cells in sleep deprivation(SD)mice.Methods A total of 42 C57BL/6 mice were divided into three groups according to the random number table method(n=14):a control(Ctrl)group,a sleep deprivation(SD)group and a SD+U99194A(U)group.Mice in the SD and U groups were deprived of sleep for three days by the multi‑platform water environment meth‑od.Meanwhile,mice in the U group were intraperitoneally injected with 20 mg/kg U99194A daily for three days,while those in the Ctrl and SD groups were intraperitoneally injected with the same amount of normal saline.The cognitive functions of the mice were assessed by Morris water maze.The expression of trypsin in hippocampal mast cells was observed by immunohistochemistry.The amounts of in‑terleukin(IL)‑6,tumor necrosis factor‑α(TNF‑α)and IL‑1βin the hippocampus were measured by Enzyme‑linked immunosorbent as‑say(ELISA)kits.Results There was no significant difference as to escape latency in five‑day spatial navigation development before sleep deprivation among the three groups(P>0.05).The SD and U groups showed limited space exploration trails in the target quadrant(the third quadrant),compared with the Ctrl group.The U group showed increased space exploration trails in the target quadrant,com‑pared with the SD group(P<0.05).Compared with the Ctrl group,the SD and U groups showed prolonged escape latency,a decreased number of crossing the platform,shortened stay in the target quadrant,as well as an increased content of trypsin in the hippocampus of mice,and increased contents of IL‑6,TNF‑α,and IL‑1βin the hippocampus(P<0.05).Compared with the SD group,the U group showed shortened escape latency,an increased number of crossing the platform,prolonged stay in the target quadrant,as well as a de‑creased content of trypsin in the hippocampus of mice,and decreased contents of IL‑6,TNF‑α,and IL‑1βin the hippocampus(P<0.05).Conclusions U99194A can improve the cognitive function of SD mice,which may be related to inhibition of mast cell activa‑tion to suppress neuroinflammation.