慢性应激抑郁模型大鼠海马组织SIOOB表达及氟西汀的干预作用

目的探讨慢性应激抑郁模型大鼠脑内S100B表达与抑郁样行为之间的关联及氟西汀的干预作用。方法40只成年雄性SD大鼠随机数字表法分为对照组、氟西汀组、应激组和应激加氟西汀组。依组名接受相应应激和（或）氟西汀干预。应激于实验第1～42天进行，为慢性不可预见性应激；氟西汀干预5mg／（kg·d），灌胃]于实验22～42d进行。行为学评定采用旷场试验，蔗糖水消耗试验及体质量测定，分别于实验前、实验21d及42d进行。用免疫组化法观察比较干预结束后各组大鼠CA1、CA2、CA3、DG区及前额皮质S100B表达水平。结果应激42d使大鼠行为学评分明显下降（应激单独效应，均P〈0．05），21d氟西汀干预逆转上述过程（交互作用，均P〈0．05）。应激使大鼠脑内CA1、CA3、DG区SIOOB表达升高（平均光密度，应激组分别为0．331±0．01，0．353±0．01，0．381±0．007；对照组分别为0．238±0．007，O．237±0．010，0．228±0．006。应激单独效应，P=0．000；P=0．000；P=0．000）。氟西汀逆转应激对CA1、CA3、DG区S100B表达的影响（平均光密度，应激＋氟西汀组为O．233±0．015，0．240±0．005，0．254±0．015；氟西汀组分别为0．241±0．007，0．233±0．013，0．227±0．017。氟西汀与应激交互作用，P=0．000；P=0．000；P=0．000）。结论慢性不可预见性应激所致大鼠抑郁样表现与海马内CA1，CA3，DG区S100B过度表达有关；逆转海马内S100B过度表达是氟西汀抗抑郁有效的标志而非作用机制。

Expression of SIOOB in hippocampus of depression model rats induced by chronic unpredictable stress andthe effect of fluoxetine in bolcking it

Objective To explore the relationship between expression of S100B in hippocampus of de- pression model rats induced by chronic stress and its depression like behavior, and the antidepressant effect of flu- oxetine. Methods 40 rats were put into control group, fluoxetine group, CUS group and CUS plus fluoxetine group, using random number table. Rats in each groups received corresponding treatment. Chronic unpredictable stresses（CUS） were performed on rats for 42 days. Fluoxetine（ 5 mg/（ kg ~ d） ） were delivered to rats by intragas- tric administration from day 22 to day 42. Then, S100B protein were marked and observed by immunohistochemical method. Open-field test, sucrose consumption and body weight were used to evaluate behavioral changes. Re- suits Scores in behavioral test were reduced significantly by 42 days of stress （ main effects of stress, P〈0.05 ） . Effects of stress on behavioral scores were reversed by 21 days fluoxetine treatment （interactions, P〈0.05）. CUS resulted in elevated expression of S100B in CA1, CA3 and DG sub-regions in experimental rats （OD values, CUS, 0.331 ±0.01,0.353 ± 0.01,0.381 ±0.007 ; control, 0.238 ± 0. 007 , 0. 237± 0.010,0.228 ±0.006. Simple effects of stress, P= 0.000; P= 0.000; P= 0.000）. Fluoxetine treatment reversed the elevated expression of S100B in CA1, CA3 and DG sub-regions in model rats （ OD values ： CUS plus fluoxetine, 0. 233 ± 0. 015 , 0. 240± 0.005,0.254± 0.015; fluoxetine,0.241±0.007,0.233±0.013,0.227±0.017; Interactions between fluoxetine and CUS, P= 0.000; P=0.000; P=0.000）. Conclusion Sub-regional over expression of S100B in hippoeampus is associated with de- pression like behavior of rats. Reversed S100B expression in these sub-regions is an indicator of effective antide- pressant treatment but not a mechanism for it.