阻断促肾上腺皮质激素释放激素1受体对慢性束缚应激致大鼠类抑郁症状的改善

Blocking corticotropin-releasing hormone 1 receptor regulates expression of BDNF and GAP-43 in hypothalamus of depression rats induced by chronic restraint stress

目的研究束缚应激对大鼠下丘脑脑源性神经营养因子(brain derived neurotrophic factor,BDNF)和生长相关蛋白(growth associated protein 43,GAP-43)表达的影响,并分析BDNF和GAP-43在慢性应激致类抑郁样症状发生中的作用以及CP-154526的治疗作用。方法将30只雄性SD大鼠随机分成3组,即束缚应激组、CP-154526治疗组和对照组。束缚应激组采用每日束缚3 h、连续21 d的方法建立抑郁症模型,促肾上腺皮质激素释放激素1受体(corticotrophin-releasing hormone type 1receptor,CRH1R)阻断剂CP-154526治疗组自实验开始用CP-154526对抑郁模型动物予以治疗,对照组注射CP-154526的溶剂DMSO。观测各组大鼠行为学变化;酶联免疫吸附实验检测血浆促肾上腺皮质激素释放激素(corticotropin releasing hormonecorti,CRH)浓度;Western blot检测模型大鼠下丘脑BDNF、GAP-43蛋白表达表达情况。结果束缚应激组与对照组和治疗组相比体质量增长下降(P<0.05)、和糖水偏好率均显著下降(P<0.05),在穿格次数、站立次数、修饰次数均少于对照组(P<0.05);而治疗组与对照组以上实验结果无统计学差异(P>0.05)。束缚应激组血浆CRH浓度较对照组升高(P<0.05),但治疗组血浆CRH浓度较对照组无统计学差异(P>0.05)。束缚应激组下丘脑BDNF、GAP-43表达较对照组与治疗组增多(P<0.05)。结论慢性束缚应激可致大鼠下丘脑BDNF、GAP-43蛋白表达上调,导致下丘脑发生可塑性变化,与下丘脑CRH分泌增多以及抑郁症行为的变化相关。CRH1R阻断剂CP-154526可逆转下丘脑BDNF和GAP-43蛋白的表达,改善类抑郁症状。

Objective To determine the effect of chronic restraint stress on the expression of brain derived neurotrophic factor（ BDNF） and growth associated protein 43（ GAP-43） in the hypothalamus of rats,the role of BDNF and GAP-43 in the pathogenesis of depression induced by chronic restraint stress,and the regulation effect of CP-154526 [corticotrophin-releasing hormone type 1 receptor（ CRH1R） antagonist].Methods A total of 30 male Sprague-Dawley rats were randomly divided into 3 groups： restraint stress group,CP-154526 treatment group and control group. The rats were restrained for 3 h daily over a period of21 d to construct depression model. The treatment group was injected with CP-154526 from the beginning of the experiment,while the control group was injected with dimethyl sulfoxide（ solvent of CP-154526）. Then the behaviors of the rats were observed. The level of corticotrophin-releasing hormone（ CRH） in the blood serum was detected by enzyme-linked immunosorbent assay（ ELISA）,and the expression of BDNF and GAP-43 in the hypothalamus was verified by Western blotting. Results Compared with the control group and the CP-154526 treatment group,the restraint stress group showed decreased body weight（ P 0. 05）,reduced sucrose preference（ P 0. 05）,and decreased spanning lattice times,standing times and modification times（ P 0. 05）. There was no statistical difference between the CP-154526 treatment group and the control group in the above tests（ P 0. 05）. The restraint stress group showed significant increase in the serum CRH concentration compared with the control group（ P 0. 05）,but there was no significant difference between the CP-154526 treatment group and the control group（ P 0. 05）. Compared with the control group and CP-154526 treatment group,the restraint stress group showed higher expression of BDNF and GAP-43 in the hypothalamus（ P 0. 05）. Conclusion Chronic restraint stress can induce up-regulation of BDNF protein and GAP-43 protein in the hypothalamus,and lead to plastic changes in the hypothalamus,which are consistent with the changes of CRH secretion and depression-related behavior. CP-154526 significantly alleviates the symptoms of depression through inhibiting the up-regulation of BDNF protein and GAP-43 protein in the hypothalamus.