氯胺酮联合氟西汀对抑郁大鼠前额叶nNOS及其配体CAPON表达的影响

Effects of ketamine plus fluoxetine on nNOS and CAPON expression in the prefrontal lobe of mentally depressed rats

目的 探讨氯胺酮联合氟西汀对抑郁大鼠行为学以及对大鼠脑内前额叶神经型一氧化氮合酶（nNOS）羧基末端PDZ配体（CAPON）的影响。方法 健康成年♂SPF级SD大鼠,体重220～270g,2.5～3mon龄,采用慢性轻度不可预见性应激法建立抑郁模型。选建模成功的大鼠96只,采用随机数字表法,将其随机分为4组（n=24）：抑郁对照组（D组）、氯胺酮组（K组）、氟西汀组（F组）及氯胺酮联合氟西汀组（KF组）。再根据给予药物处理时间的不同,各组随机分为2个亚组（n=12）：处理3d组（D3、K3、F3、KF3）和处理7d组（D7、K7、F7、KF7）。D组行空白对照处理,K组给予氯胺酮10mg·kg^-1腹腔注射;F组给予氟西汀1.8mg·kg^-1灌胃;KF组氯胺酮10mg.kg-1腹腔注射后,即刻给予氟西汀1.8mg·kg^-1灌胃。根据所在亚组分别给予各组连续3d或7d处理,每天1次。于建模前1d,建模后1d及药物处理结束后1d采用旷场实验和糖水偏好实验评价其抑郁状态。所有行为学检测完成后1d处死大鼠,分别采用免疫组织化学法和RTPCR法检测前额叶nNOS、CAPON蛋白及其mRNA的表达。结果 与建模前比较,各组大鼠建模后水平运动距离、直立次数减少,糖水偏好比下降（P〈005）,且各组间差异无统计学意义（P〉005）。在药物处理3d后,与D3组比较,K3组和KF3组水平运动距离、直立次数增多,糖水偏好比升高,nNOS及其mRNA表达下调,CAPON蛋白及其mRNA表达上调（P〈005）。在药物处理7d后,与D7组比较,K7组,F7组和KF7组水平运动距离、直立次数增多,糖水偏好比升高,nNOS及其mRNA表达下调,CAPON蛋白及其mRNA表达上调（P〈005）;与F7组比较,KF7组水平运动距离、直立次数增多,糖水偏好比升高,nNOS及其mRNA表达下调,CAPON蛋白及其mRNA表达上调（P〈005）。结论 氯胺酮联合氟西汀较单独使用氟西汀对抑郁大鼠的抗抑郁作用更强,且抗抑郁起效时间缩短,其机制可能与氯胺酮联合氟西汀可降低大鼠脑内前额叶nNOS表达及升高其配体CAPON的表达有关。

Aim To investigate the effect of ketamine plus fluoxetine on depressed behavior and the expression of neuronal nitric oxide synthase（ n NOS） and CAPON in prefrontal lobe of mentally depressed rats at different time points,so as to study the possible mechanism of ketamine plus fluoxetine inducing antidepressant behavior. Methods Healthy adult male SpragueDawley rats,aged 2. 5 ~ 3 months,weighing 220 ~ 270 g,were induced as the rodent model of depression by chronic unpredictable mild stress（ CUMS）. After the models of depression were established,96 of CUMS modeling successfully depressed rats were selected.Then they were randomly divided into four groups（ n =24 each） ： the depressed group（ group D,untreated group）,ketamine group（ group K,treated with intraperitoneal injection of ketamine 10 mg·kg^- 1once a day for 3 days or 7 days）,fluoxetine group（ group F,treated with gavage of fluoxetine 1. 8 mg·kg^- 1once a day for 3 days or 7 days）,or ketamine plus fluoxetine group（ group KF,treated with intraperitoneal injection of ketamine 10 mg·kg^- 1plus gavage of fluoxetine 1. 8mg · kg^- 1once a day for 3 days or 7 days）. Open field test and sucrose preference test were performed 1day before depression model was established,and 1day before and after treatment. The rats were sacrificed1 day after the last test for determination of the expression of n NOS and CAPON protein（ using immuno-histochemisity） and mRNA（ by RT-PCR） in the prefrontal lobe. Results After the models of depression were established,the total distance,rearing number and the sucrose preference percentage（ SPP） were decreased significantly compared with those before（ P 〈0. 05）.There was no significant difference among all groups in the total distance,rearing number and the SPP before treatment（ P〈 0. 05）. Compared with groups D and F,the total distance was prolonged,the number of rearing and SPP were significantly increased,the expression of n NOS protein and mRNA was down-regulated and the expression of CAPON protein and mRNA was up-regulated in groups K and KF,with 3 days＇ treatment（ P〈 0. 05）. Compared with group D,the total distance was prolonged,the number of rearing and SPP were significantly increased,the expression of n NOS protein and mRNA was down-regulated and the expression of CAPON protein and mRNA was up-regulated in groups K,F and KF with 7 days ＇ treatment（ P 〈0. 05）. Compared with group F,the total distance was prolonged,the number of rearing and SPP were significantly increased,the expression of n NOS protein and mRNA was down-regulated and the expression of CAPON protein and mRNA was up-regulated in group KF with 7 days＇ treatment（ P 〈0. 05）. Conclusion Coadministration of antidepressant fluoxetine with ketamine may induce a more pronounced antidepressant activity than treatment with each antidepressant alone and it can shorten the time to improve the depressive state through promoting the expression of CAPON and inhibiting n NOS activity in the prefrontal lobe of mentally depressed rats.