母鼠慢性不可预见性应激后对子代大鼠海马脑源性神经营养因子表达的影响

Effect of progestational stress on the expression of brain-derived neurotrophic factor in hippocampus of the offspring rats

【目的】探讨母鼠接受慢性不可预见性应激(chronic unpredictable stress,CUS)后短期内受孕对1月龄子代大鼠大脑海马中脑源性神经营养因子(brain-derived neurotrophic factor,BDNF)表达的影响。【方法】SD系成年雌性大鼠随机分为正常对照母鼠组(8只)和CUS母鼠组(12只)。采用11种刺激方法对CUS母鼠组进行21 d慢性不可预见性应激。于应激前、后,两组母鼠进行开场试验及蔗糖水消耗试验,分析CUS对母鼠自主行为的影响。用免疫组织化学染色和实时聚合酶链反应(Realtime Polymerase Chain Reaction,RT-PCR)法检测1周内受孕的CUS母鼠组所得子代大鼠(雌雄各30只)1月龄时海马中BDNF的表达情况,并与同期受孕的正常对照母鼠组所产子代大鼠进行同性别间的比较。【结果】CUS母鼠组应激后开场试验的总路程、周边路程、中央路程和蔗糖水消耗试验的蔗糖水消耗量明显少于应激前及正常对照母鼠组。子代大鼠海马中BDNF免疫反应阳性细胞的相对灰度值在正常雌性子代组为42.4±6.9,CUS雌性子代组为36.1±8.5(P<0.05);在正常雄性子代组为43.7±6.4,CUS雄性子代组为39.6±8.4(P<0.05)。子代大鼠海马中BDNF mRNA的表达量在正常雌性子代组为6.65±0.26,CUS雌性子代组为4.55±0.37(P<0.05);在正常雄性子代组为6.77±0.20,CUS雄性子代组为4.75±0.30(P<0.05)。【结论】母鼠接受慢性不可预见性应激后短期内受孕,会使子代大鼠海马中BDNF mRNA转录水平显著下降,而且这种改变与BDNF阳性细胞在海马中表达减少一致。

【Objective】To investigates the effect of progestational stress on the expression of brain-derived neurotrophic factor（BDNF） in hippocampus of the offspring rats when they were one month old. 【Methods】Adult female SD rats which as the maternal rats were randomly divided into two groups： control group and CUS group.The maternal rats of chronic unpredictable stress（CUS） group accepted 21 days CUS which consisted of eleven different stressors.All maternal rats were tested in the open field test and sucrose intake test before and after CUS protocol.When the procedure of CUS finished,maternal rats were housed by pairs which were the same group for 1 week with a male rat for mating.When the offspring rats were one months old,they were divided into four groups： female offspring of control group（n=30）,male offspring of control group（n=30）,female offspring of US group（n=30）.male offspring of CUS group（n=30）.The expression of BDNF in hippocampus of the offspring rats were studied by immunoreactivity quantitative analysis and RT-PCR. 【Results】1）CUS group showed decrease activities in the open field test and decrease sucrose comsumption in sucrose intake test compared to control group.2）Immunoreactivity quantitative analysis shows that the gray values of BDNF in the female offspring of CUS group（36.1±8.5）was decreased than control group（42.4±6.9）,as well as the male offspring of CUS group（39.6±8.4）comparing with control group（43.7±6.4）.3）RT-PCR shows that the level of BDNF mRNA in the hippocampus of female offspring of CUS group（4.55±0.37）was less than control group（6.65±0.26）,as well as male offspring of CUS group（4.75±0.30）comparing with control group（6.77±0.20）. 【Conclusion】Progestational stress reduce the expression of BDNF in hippocampus of the offspring rats,which the decrease of the level of BDNF mRNA is consonance with the gray values of BDNF immunoreactivity positive cells.