[目的]初步探讨青少期应激结合成年后诱导抑郁大鼠海马CA1区细胞形态与5-羟色胺转运体(5-HTT)蛋白表达的变化及加味四逆散的干预作用.[方法]将132只Wistar大鼠随机分成空白组、模型组、加味四逆散组、氟西汀组,共4组,每组33只;组内再随机分为青少期、成年期、成年后3个小组,每小组11只.选取44、56、78 d 3个时间点作为青少期、成年期、成年后3个阶段的取材时间点.复制慢性不可预知应激(CUMS)大鼠模型.于第21～44天、第57～78天造模及给药,第44～55天正常喂养,不予造模及给药.观察各组大鼠的一般状况与体质量变化,采用苏木素—伊红(HE)染色法观察海马CA1区细胞形态,采用免疫组化染色法观察海马CA1区5-HTT阳性细胞的分布变化.[结果]模型组青少期、成年期、成年后大鼠一般状况较差,而经加味四逆散及氟西汀治疗后的大鼠均得到明显改善.各阶段的模型组大鼠体质量较同阶段的空白组显著降低(P<0.01);成年后,与空白组比较,其余3组体质量均显著降低(P<0.01),且3组间比较,差异无统计学意义(P>0.05).在海马CA1区细胞形态表现方面,模型组青少期较多神经元萎缩、深染,胞核、胞浆界限不清,成年期及成年后呈进行性加重,大量神经元深染,胞核、胞浆界限不清,并有少量胶质细胞增生;而氟西汀组、加味四逆散组与同阶段模型组比较,神经元萎缩、深染减少.5-HTT表达结果显示,成年期、成年后模型组5-HTT的平均光密度值较同阶段的空白组显著降低(P<0.05或P<0.01),成年后加味四逆散组,成年期、成年后氟西汀组5-HTT的平均光密度值值较同阶段的模型组有显著升高(P<0.05或P<0.01).[结论]在青少期受到CUMS的大鼠可产生抑郁样行为,成年后继续施加刺激诱导会进一步加重抑郁状态.抑郁大鼠海马内5-HTT改变可能是加味四逆散干预作用的重要通路.%Objective To investigate the cell morphology and expression of 5-hydroxytryptamine transporter(5-HTT) in hippocampal CA1 region of depression rats induced by adolescent and post-adult stress,and to observe the inter-vention effect of modified Sini San (MSS). Methods One hundred and thirty-two Wistar rats were randomly divided into blank group,model group,JSS group,and fluoxetine group,33 rats in each group. And then the rats in each group were randomly subdivided into adolescent group, adult group, post-adult group acaccording to the age day, 11 rats in each subgroup. Age day 44,56 and 78 were used as the sampling time points for adolescent group,adult group,post-adult group respectively. Chronic unpredictable mild stress(CUMS)rat model was used. From day 21 to 44 and from day 57 to 78, the rats were modeled and given medication, but from day 44 to 55, the rats were fed normally. The rat general condition and body mass of various groups were observed,the cell morphology of hippocampal CA1 region was observed by hematoxylin-eosin (HE) staining , and the distribution of 5-hydroxytryptamine transporter (5-HTT)positive cells in CA1 region of hippocampus was observed by immunohistochemical staining. Results The general condition of the rats at different age stages in the model group was poor,while that in MSS group and fluoxetine group was improved obviously. The body mass of rats at different age stages in the model group was obviously decreased (P<0.01 compared with the blank group). After adulthood stage,the body mass of rats in model group, MSS group, and fluoxetine group was lower than that of the blank group(P < 0.01), but there was no difference between the 3 groups (P > 0.05). In aspect of cell morphological manifestation in hippocampal CA1 region, rats in the adolescent model group had more deeply-staining atrophy neurons, with unclear hyperchromatic nucleus and cytoplasm. The morphological manifestations in modeled rats at adult stage and post-adulthood stage showed progressive aggravation,manifested as a large amount of neurons stained deeply with unclear nucleus and cytoplasm, and a small amount of glial cells proliferated. Compared with the model group at the same stage,the neuronal atrophy and deeply staining decreased in fluoxetine group and MSS group. The average optical density value of 5-HTT expression in the model group was decreased significantly at the adult stage and after adulthood stage(P<0.05 or P<0.01 compared with the blank group). Compared with the model group, the average optical density value of 5-HTT expression in MSS group after adulthood stage, and in the fluoxetine group at the adult stage and after adulthood stage were increased (P<0.05 or P<0.01). Conclusion Rats suffering CUMS in adolescence presents depressive behavior, and post-adult stimulation can aggravates depression. 5-HTT expression in hippocampus may be an important pathway for MSS to achieve the therapeutic efficacy.
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