降低脑脊液miR-16的水平对大鼠抑郁样行为的影响

Effects of decreasing miR-16 in cerebrospinal fluid on depression-like be⁃haviors in rats

目的:探讨降低脑脊液微小RNA-16(miR-16)的水平是否通过影响中缝核miR-16与5-羟色胺转运体(SERT)的表达参与抑郁症的发病。方法:SD大鼠侧脑室分别注入生理盐水、阴性对照液及miR-16拮抗剂5、10和20 nmol,隔天1次,共3次。而后进行蔗糖偏好实验和强迫游泳实验,并取脑脊液与中缝核组织,通过RTqPCR法测定miR-16水平,Western blot法测定SERT蛋白水平。结果:拮抗剂10和20 nmol组蔗糖偏好率[(46.67±9.35)%和(40.28±10.54)%]显著低于空白对照组[(54.72±11.25)%]和阴性对照组[(53.34±13.71)%],不动时间[(30.54±12.78)s和(36.23±8.57)s]则明显长于空白对照组[(16.71±5.58)s]和阴性对照组[(19.15±7.46)s](P<0.05),随着miR-16拮抗剂剂量的增加,抑郁样行为越明显。与空白对照组和阴性对照组相比,中缝核miR-16水平在拮抗剂3组均下降,并与注射剂量呈负相关(r=−0.57,P=0.000),中缝核中SERT蛋白水平则相反。结论:降低脑脊液miR-16水平可影响大鼠中缝核miR-16及SERT的表达,并与抑郁症的发病机制相关。

AIM:To study whether decreasing microRNA-16(miR-16)level in cerebrospinal fluid(CSF)participates in the mechanism of depression via regulating the expression of miR-16 and serotonin transporter(SERT)in raphe nuclei.METHODS:SD rats were intracerebroventricularly injected with the normal saline,negative oligonucle⁃otide control and 5,10 and 20 nmol miR-16 anatagomir,respectively,every other day for 3 times.Then,sucrose prefer⁃ence test and forced swimming test were performed.After that,CSF and raphe nuclei were collected.RT-qPCR was used for miR-16 examination and Western blot was performed for SERT determination.RESULTS:The antagomir at 10 and 20 nmol had obvious effect to decrease sucrose preference rates[(46.67±9.35)%and(40.28±10.54)%]as compared with saline group(54.72±11.25)%and negative control group(53.34±13.71)%,while the immobility time of these 2 groups[(30.54±12.78)s and(36.23±8.57)s]were significantly higher than those in saline group(16.71±5.58)s and nega⁃tive control group(19.15±7.46)s(P<0.05).The depression-like behaviors were more obvious with the increasing of an⁃tagomir injection dose.The miR-16 levels in raphe nuclein of the 3 antagomir groups were all decreased(F=6.174,P=0.000)and negatively correlated with the injecting doses of antagomir(r=−0.57,P=0.000).On the contrary,the pro⁃tein expression of SERT in raphe nuclei was opposed to the results of miR-16 level.CONCLUSION:Decrease miR-16 level in CSF affects the expression of miR-16 and SERT in raphe nuclei,which may be associated with the mechanism of depression.