摘要:
目的 观察母婴分离(maternal separation,MS)对青年期小鼠海马和前额叶皮质糖皮质激素受体(glucocorticoid receptor,GR)和微管相关蛋白(doublecortin,DCX)表达的影响.方法 将15只怀孕小鼠随机分为5组:对照组,母婴分离3d、7d、14d、21d组,每组3只孕鼠.对照组新生鼠出生后与母鼠同笼喂养不做任何处理,实验组新生鼠自出生后每天与母鼠分离3 h,所有仔鼠于出生后23 d断乳,雌雄分笼,雄性小鼠喂养至42 d处死取脑.用免疫组织化学染色法和Image J图像分析技术检测海马和前额叶皮质区GR和DCX的表达和分布.结果 母婴分离3 d、7 d、14 d、21 d组小鼠海马GR阳性细胞平均光密度值、前额叶皮质GR阳性细胞平均光密度值和海马齿状回颗粒下层DCX阳性细胞平均光密度值[海马GR:3 d(0.332±0.054)OD/μm2,7 d(0.258±0.045)OD/μm2,14 d(0.197±0.043)OD/μm2,21 d(0.164±0.053)OD/μm2;前额叶皮质GR:3 d(0.356±0.043)OD/μm2,7 d(0.278±0.041)OD/μm2,14 d(0.220±0.039)OD/μm2,21 d(0.157±0.034)OD/μm2;海马齿状回DCX:3 d(0.193±0.020)OD/μm2,7 d(0.146±0.033)OD/μm2,14 d(0.110±0.032)OD/μm2,21 d(0.060±0.017)OD/μm2]均低于对照组,且随分离重复时间的增长呈递减的趋势,其中7 d、14 d、21 d组小鼠平均光密度值明显低于对照组小鼠,差异有统计学意义(P<0.05);实验各组之间平均光密度值比较差异有统计学意义(P<0.05).结论 MS会引起青年期小鼠海马和前额叶皮质GR降低,海马齿状回颗粒下层神经发生减少,且分离重复时间越长,对下丘脑-垂体-肾上腺轴和神经发生影响越大.%Objective To observe the effect of maternal separation( MS) on the expression of glu-cocorticoid receptor ( GR ) and doublecortin ( DCX ) in hippocampus and prefrontal cortex of young mice. Methods Fifteen pregnant mice were randomly divided into 5 groups:the experimental group ( 3 d, 7 d, 14 d,21 d) and the control group, n=3 in each group. Neonatal mice in experimental group were separated from mother for 3 h once a day,and the mice in control group were caged with mother without any processing after birth. All mice were weaned in postanal day 23. Separating female and male mice,and the male mice were killed and the brains were taken in postanal day 42. The expression and distribution of GR and DCX in hippocampus and prefrontal cortex were determined by immunohistochemical staining and Image J image a-nalysis technique. Results The average optical density values of GR positive cells in hippocampus and pre-frontal cortex,the average optical density values of DCX positive cells in hippocampal dentate gyrus subgran-ular zone in 3 d,7 d,14 d and 21 d group were(GR in hippocampus:3 d((0.332±0.054)OD/μm2,7 d (0.258±0.045)OD/μm2,14 d(0.197±0.043)OD/μm2,21 d(0.164±0.053)OD/μm2),(GR in prefrontal cortex:3 d(0.356±0.043)OD/μm2,7 d(0.278±0.041)OD/μm2,14 d(0.220±0.039)OD/μm2,21 d(0.157 ±0.034)OD/μm2)and(DCX in hippocampus:3 d(0.193±0.020)OD/μm2,7 d(0.146±0.033)OD/μm2, 14 d(0.110±0.032)OD/μm2,21 d(0.060±0.017)OD/μm2)were lower than those in control group,which showed a decreasing trend with the increase of seperation time,and the average optical density values in 7 d, 14 d and 21 d group were obviously lower than those in control group(P<0.05) . The average optical density values had statistical significance among the experimental groups(P<0.05) . Conclusion MS can cause the decrease of GR in hippocampus and prefrontal cortex and reduce neurogenesis in the hippocampal dentate gy-rus subgranular zone in young mice. It shows that the longer the seperation time,the greater the effect on hy-pothalamic-pituitary-adrenal( HPA) axis and neurogenesis.