慢性应激诱导的抑郁大鼠海马脑源性神经营养因子蛋白和miR-16的表达

目的 研究慢性应激对大鼠行为及海马中脑源性神经营养因子（BDNF）和microRNA-16（miR-16）表达的影响.方法 在大鼠出生后1d,按窝别分为慢性应激组和对照组,各6只.慢性应激组大鼠在其出生后第1-14天每天接受6h母爱剥夺应激,然后喂养至10周龄时给予21d慢性温和应激,对照组不给予任何处理.两组大鼠均于13周龄时,采用强迫游泳、糖水偏爱和旷场试验测定大鼠的行为,采用免疫印迹法检测BDNF蛋白的表达情况,采用实时定量聚合酶链反应检测海马miR-16表达水平.结果 旷场实验中,应激组大鼠直立次数少于对照组（P＜0.05）,而爬行总路程,中央格比例和大便颗数差异均无统计学意义（P＞0.05）;强迫游泳实验中应激组大鼠的被动漂浮时间长于对照组（P＜0.05）;糖水测验中应激组大鼠的糖水偏爱率低于对照组（P＜0.05）.应激组大鼠海马BDNF蛋白表达量低于对照组（P＜0.05）;应激组大鼠海马内miR-16的表达量高于对照组（P＜0.05）.Pearson相关分析显示,两组大鼠的miR-16表达水平均与BDNF蛋白表达水平呈负相关（P＜0.05）.大鼠直立次数和糖水偏爱率分别与海马内BDNF蛋白表达量与呈正相关（P＜0.05）,与miR-16表达量呈负相关（P＜0.05）而被动漂浮时间与海马内BDNF蛋白表达量呈负相关（P＜0.05）,与miR-16表达量呈正相关（P＜0.05）.结论 慢性应激可导致大鼠抑郁样行为的出现及海马中miR-16与BDNF蛋白表达发生改变,并且大鼠的抑郁样水平与海马中miR-16和BDNF蛋白表达水平明显相关;大鼠海马中miR-16与BDNF蛋白可能参与了调节抑郁症的病理过程.

Chronic stress-induced depressive behaviors correlated with BDNF and miR-16 expression in rat hippocampus

Objective To study the expression of brainderived neurotrophic factor （BDNF） and mieroRNA--16 （miR--16） in hippocampus of depressed rats induced by the chronic unpredictable stress , and to investigate whether miR--16 is involved in the regulation of the process in which BDNF gene mediated rats＇ depressive behaviors during chronic stress response. Methods Newborn SD rats were randomly divided into two groups. The stress group rats （n = 6） were deprived from their mothers 6 hours per day from postnatal day 1 to 14 and received continuous 21 days chronic unpredictable stressors when 10 weeks old while the control group rats （n =6） received no experimental handle. When they grew up to 13 weeks, depressive behaviors were assessed with forced swimming test, sucrose preference test and open field test. The expressions of miR--16 and BDNF protein in rats＇ hippocampus were detected by re- al-time Polymerase Chain Reaction （Real--time PCR） and Western Blotting respectively. Results In the open field test, the number of vertical activity of the stress group was significantly less than that of the control group （P 〈 0.05）. The total distance, the central area rate and the number of the fecal pel- lets were not different between two groups （P〈0.05）. In the forced swimming test, the floating time of the stress group was significantly longer than that of the control group （P 〈 0.05）. In the sucrose pref erence test, the stress group consumed significantly less sucrose than control group did （P 〈0.05）. The expression of BDNF protein in stress group was significantly lower than that in control group （P 0.05）. The expression of miR--16 in stress group was significantly higher than in control group （P 0.05）. Pearson correlation analysis revealed that the expression of miR-- 16 was negatively correlated with the expression of BDNF in hippocampus （P 〈0.05）. The number of vertical activity and the su- crose preference were negatively correlated with the expression of BDNF