甘丙肽系统在雌性焦虑抑郁样小鼠海马中的表达和作用

The expression and function of galanin system in the hippocampus of anxiety-and depression-like behavior female mice

目的研究在雌性焦虑抑郁样行为小鼠海马中甘丙肽及其受体的表达和所起的作用。方法制备甘丙肽及甘丙肽受体-1(galanin receptor subtybe 1,Gal R1)、受体-2(Gal R2)、受体-3(Gal R3)探针,运用原位杂交技术观察甘丙肽及其受体Gal R1、Gal R2、Gal R3在雌性C57BL/6J小鼠海马中分布情况。另取雌性C57BL/6J小鼠随机分为实验组(15只)与对照组(15只),实验组给予慢性温和型不可预见性刺激(chronic unpredictability mild stress,CUMS)4周,对照组不给予任何刺激。4周后分别行糖水偏好实验、新物体识别实验、旷场实验及悬尾实验以评估小鼠的焦虑抑郁样行为水平及工作记忆情况;行为实验后,每组8只小鼠提取海马RNA行qPCR以检测海马甘丙肽及其受体表达情况,其余小鼠取脑行免疫荧光染色检测海马C-Fos阳性细胞数。结果原位杂交结果显示甘丙肽及其受体Gal R1、Gal R2在腹侧海马Hilus区有表达,Gal R3未见阳性信号。糖水偏好实验实验组较对照组糖水饮用量减少(P<0.05);新物体识别实验显示,实验组比对照组探索新物体时间百分比短(P<0.05);旷场实验中,实验组小鼠较对照组中间停留时间缩短(P<0.05);悬尾实验中,实验组较对照组累计静止时间延长(P<0.05)。qPCR结果示实验组小鼠海马甘丙肽及Gal R1表达较对照组增高(P<0.05)。免疫组化结果示实验组小鼠海马齿状回C-Fos阳性细胞较对照组增多(P<0.05)。结论甘丙肽、Gal R1及Gal R2主要分布在小鼠海马的腹侧Hillus区;在雌性C57BL/6J小鼠中,海马甘丙肽及Gal R1的增加可能与焦虑抑郁样行为有关,与海马齿状回C-Fos细胞增加也有关。

Objective To explore the expression and function of galanin and its receptor in the female mice of anxiety-and depression-like behavior. Methods In situ hybridization was used to detect the expression of galanin, GalR1, GalR2 and GalR3 in the hippoeampus of C57BL/6J female mice. A total of thirty female mice was divided into two groups： experiment group （n=15） and control group （n=15）. The experiment group was subjected to the chronic unpredictable mild stress （CUMS） for four weeks, and the control group was not subjected to any treatment. Four weeks later, a series of tests were performed on those two groups, including the sucrose preference test, the novel object recognition test, the open field test and suspension tail test. After behavior tests, the hippocampus RNA was extracted from eight mice in each group to test the expression of galanin and its receptor through qPCR. The rest part of mice were used to mark C-Fos immunostaining in the dentate gyms （DG） of hippocampus. Results The result of in situ hybridization showed that galanin ,GalR1 and GalR2 distributed in the Hillus of ventral hippocamous, GalR3 had no positive signal. In the sucrose preference test, the experiment group drunk less sucrose when compared with the control group （P〈0.05）. In the novel object recognition test, the experiment group contacted shorter time to the novel object when compared with the control group （P〈0.05）. In the open field test, the experiment group had shorter in session time when compared with the control group （P〈0.05）. In the suspension tail test, the experiment group had longer immobility time when compared with the control group （P〈0.05）. The qPCR result showed that the higher expression of galanin and GalR1 in the hippocampus of experiment group （P〈0.05）. More C-Fos positive cells in the DG of hippocampns of experiment mice were immunostained （P〈0.05）. Conclusions Galanin, GalR1 and GalR2 mainly distribute in the Hillus of the ventral hippocampus. Galanin may be involved in the anxiety- and depression-like behavior of C57BL/6J through GalR1.