小鼠在强迫游泳应激下脑区激活情况的研究

Study on the Activation of Brain in Mice under Forced Swimming Stress

目的:探究小鼠在强迫游泳应激下各脑区激活情况。方法:选用健康的6~8周龄野生型C57小鼠11只,随机分为应激组(FS)5只和对照组(Ctl)6只。给予应激组小鼠冰水浴强迫游泳刺激,对照组不做处理。麻醉后灌流固定脑组织并取脑,冰冻切片,免疫荧光染色,荧光显微镜下拍照后计数各脑区的c-fos阳性细胞数,判断冰水浴强迫游泳刺激后小鼠各脑区的激活情况。结果:应激组小鼠在内侧前额叶(mPFC:Cg1、PrL、IL),杏仁核(amygdala:BLA、BMA),伏隔核(NAc)中的c-fos阳性细胞数均高于对照组小鼠,而海马(hippocampus)脑区中应激组小鼠c-fos阳性细胞数低于对照组,其中海马回(CA)应激组小鼠低于对照组,而齿状回(DG)应激组小鼠与对照组无明显差异,梨状皮层(Pir)中的c-fos表达在应激组与对照组小鼠也无明显差异。结论:在冰水浴强迫游泳应激下c-fos在小鼠脑区内侧前额叶、杏仁核、伏隔核激活和在海马的表达下降,而梨状皮层未参与激活,提示在冰水浴强迫游泳导致的抑郁样行为过程中涉及以上几个脑区的参与。

Objective:To discuss the activation of brain regions in mice under forced swimming stress.Methods:11 healthy wild-type C57 mice of 6-8 weeks were randomly divided into the stress group(FS,n=5)and the control group(Ctl,n=6).The mice in the FS group were given ice water bath forced swimming stimulation,but the Ctl group did not.Then,the number of c-fos positive cells in brain regions was counted to estimate the activation of mice brain regions after forced swimming in ice water bath.Results:The number of c-fos positive cells in the medial prefrontal lobe(mPFC:Cg1,PrL,IL),amygdala(amygdala:BLA,BMA),and nucleus accumbens(NAc)were higher in the FS mice than in the Ctl mice.The number of c-fos positive cells in the FS mice in the hippocampus brain area was lower than that in Ctl,and the hippocampal gyrus(CA)FS mice were lower than Ctl,while the dentate gyrus(DG)FS mice had no significant difference from Ctl.There was no significant difference in c-fos expression between FS and Ctl mice in the piri-like cortex(Pir).Conclusion:Under the ice water bath forced swimming stress,the activation of brain regions in the mice involved the medial prefrontal cortex,amygdala,nucleus accumbens,but the expression of hippocampal was decreased,while the piriform cortex(Pir)did not participate in the activation,suggesting that the above several brain regions participated in the depression-like behavior caused by forced swimming in the ice water bath.