气体信号分子硫化氢对慢性不可预知性应激所致大鼠抑郁样行为的作用及机制

发布时间：2018-10-23 20:26

【摘要】：第一部分硫化氢对慢性不可预知性应激诱导的大鼠抑郁样行为的作用目的：硫化氢(hydrogen sulfide,H2S)是哺乳动物体内的一种内源性气体信号分子,在中枢神经系统具有广泛的生物学效应。研究报道,阿尔茨海默病、帕金森病、脑卒中等疾病的产生皆与脑内H2S水平失调有关。然而,脑内H2S的含量变化是否参与抑郁症的发病过程,外源性调控脑内H2S含量是否对抑郁症的治疗具有促进作用,目前鲜有报道。因此,本实验将探讨抑郁症大鼠脑内H2S水平的变化,并研究外源性补充H2S对大鼠抑郁样行为的作用。方法：应用性不可预知性温和应激(chronic unpredictable mild stress, CUMS)大鼠模型进行研究；采用气相色谱-质谱联用仪(gas chromatograph-mass spectrometer, GC-MS)检测CUMS大鼠海马脑区内源性H2S水平的改变；采用糖水偏好实验(sucrose preference test, SPT)、新奇环境摄食抑制实验(novelty-suppressed feeding test, NSFT).强迫游泳实验(forced swimming test. FST)观察大鼠抑郁样行为；采用高尔基染色观察H2S对CUMS大鼠海马神经元树突棘密度的影响；采用酶联免疫吸附测定(enzyme linked immunosorbent assay, ELISA)试剂盒来检测CUMS大鼠血清皮质酮水平。结果：CUMS大鼠海马脑区H2S含量显著降低。腹腔注射硫氢化钠(NaHS,11.2mg/kg)、吸入H2S气体(3小时,120ppm)两种给药方式,均可升高CUMS大鼠海马脑区H2S水平。腹腔注射硫氢化钠(sodium hydrosulfide, NaHS)显著降低正常大鼠急性FST的不动时间,该作用在30分钟内即可快速起效,且药效能够维持一周,其效果优于NMDA受体拮抗药MK-801和氟西汀。腹腔注射NaHS对CUMS诱导的大鼠抑郁样行为也有改善作用,即增加CUMS大鼠SPT的糖水偏好率、缩短NSFT的摄食潜伏期、降低FST的不动时间。此外,H2S可减轻CUMS所致的大鼠海马神经元树突棘密度的降低,但对大鼠血清皮质酮水平无明显影响。结论：慢性应激降低大鼠海马脑区H2S水平,而外源性补充H2S对急、慢性应激导致的大鼠抑郁样行为均有改善作用,提示调控海马脑区H2S含量可能是治疗抑郁症的新策略。第二部分硫化氢拮抗慢性不可预知性应激诱导的大鼠抑郁样行为的机制目的：近年来,氯胺酮的抗抑郁作用的发现,推动了快速起效抗抑郁药物的研究并取得了突破性进展,而对快速起效抗抑郁药物机制的探索也在不断深入。哺乳动物雷帕霉素靶蛋白(mammalian target of rapamycin,mTOR)信号及其下游通路的激活,对药物产生快速的抗抑郁作用具有重要意义。气体信号分子H2S所产生的快速抗抑郁样行为的作用机制是否与mTOR信号的激活有关?本部分实验将进行研究。方法：应用蛋白质印迹法(Western blot)检测H2S对CUMS大鼠海马脑区mTOR信号下游的P70S6k的调控作用,通过药理学阻断和分子生物学技术,并结合行为学检测,观察H2S的抗抑郁作用并探讨其作用机制。结果：Western blot实验发现H2S可迅速激活海马脑区哺乳动物雷帕霉素靶蛋白复合物1(mammalian target of rapamycin complex1, mTORC1)信号下游的核糖体蛋白S6激酶70kD (ribosomal protein S6kinases70kD, P70S6k)。而通过mTORC1特异性阻断剂雷帕霉素(rapamycin)或慢病毒载体构建mTOR调节相关蛋白(regulatory associated protein of mTOR, Raptor)的shRNA阻断mTORC1,并结合行为学检测,发现H2S的抗抑郁作用与mTORC1的激活有关。此外,H2S促进突触后密度95(postsynaptic density95, PSD95)、突触素(synaptophysin)的合成,并通过上调酪氨酸激酶受体B (tyrosine kinase receptor B, TrkB)表达,促进AMPA受体GluR1亚基总蛋白及磷酸化蛋白水平。结论：H2S通过激活mTORC1信号通路,促进突触蛋白合成,并上调TrkB受体,进一步促进AMPA受体GluRl亚基总蛋白及磷酸化蛋白水平,从而发挥抗抑郁作用。
[Abstract]:Effect of the first part of hydrogen sulfide on depression-like behavior in rats induced by chronic unpredictable stress Objective: Hydrogen sulfide (H2S) is a kind of endogenous gas signal molecule in mammals, which has extensive biology in the central nervous system. Effect: It is reported that the generation of Alzheimer's disease, Parkinson's disease, stroke and other diseases is associated with the level of H2S in the brain. However, whether the content of H2S in the brain is involved in the pathogenesis of depression, the exogenous regulation of the content of H2S in the brain can promote the treatment of depression, Therefore, this study will explore the changes of the levels of H2S in the brain of depression rats and study the effects of exogenous supplemental H2S on depression-like behavior in rats. Methods: The model of the rat model was studied by using gas chromatography-mass spectrometry (GC-MS). Gas chromatography-mass spectrometry (GC-MS) was used to detect the changes of endogenous H2S levels in hippocampus of CUMS rats. SPT), novel environment feeding inhibition experiment (SPT), NSFT). Forced swimming test (for swimmin) g test. FST) observation of depression-like behavior in rats; observation of the effect of H2S on the dendritic spines density of hippocampal neurons in CUMS rats by Golgi staining; ELISA kits were used to detect the serum of CUMS rats. Corticosterone levels. Results: brain region H of hippocampus in CUMS rats The content of 2S was significantly reduced, and both modes of administration of H2S gas (NaHS, 11.2mg/ kg) and H2S gas (3 hours, 120ppm) could increase the sea level of CUMS rats. The levels of H2S in the brain of horse brain were significantly lower than that in normal rats by intraperitoneal injection of sulfocyanide (NaHS). The effect could quickly take effect within 30 minutes, and the effect could be maintained for one week. The effect was better than that of NMDA receptor antagonist. The effect of NaHS on the depression-like behavior of the rats induced by CUMS was also improved, that is to increase the rate of appetite of the SPTs in the CUMS rats, shorten the feeding latency of the NSFT, and decrease the feeding latency of the NSFT rats. In addition, H2S can reduce the decrease of dendritic spines density in rat hippocampal neurons induced by CUMS, Conclusion: Chronic stress reduces the level of H2S in hippocampus of rats, while exogenous supplemental H2S has an improved effect on depression-like behavior in rats with acute and chronic stress. It is suggested that the content of H2S in brain region of hippocampus can be regulated and controlled. can be a new strategy for treating depression, and the second part of hydrogen sulfide antagonizes chronic unpredictable The mechanism of stress-induced depression-like behavior in rats: the discovery of anti-depressant effects of ketamine in recent years has contributed to rapid onset of action The study of anti-depressant drugs has made breakthrough progress, and fast The study of the mechanism of anti-depressant drugs has also been deepening. Activation of the mTOR signal and its downstream pathway in mammalian Repamycin target protein (mTOR) signal and its downstream pathway The rapid antidepressant action of the substance is of great significance. The rapid antidepressant action produced by the molecular H2S of the gas signal Whether or not the mechanism works with mTOR The effects of H2S on the P70S6k downstream of the mTOR signal in the hippocampus of CUMS rats were detected by Western blot. Results: Western blot showed that H2S can rapidly activate the ribosomal protein S6 kinase 70kD (ribosomal prote) downstream of the MTORC1 signal. in S6kinases70kD, P70S6k). It was found that the antidepressant effect of H2S is related to the activation of mTORC1. In addition, H2S promotes the synthesis of postsynaptic density 95 (PSD95) and synaptosin and promotes A by up-regulating the expression of tyrosine kinase receptor B (TrkB). Conclusion: H2S can promote the synthesis of synaptosin by activating mTORC1 signaling pathway and upregulate the TrkB receptor to further promote AMPA receptor Gl.
【学位授予单位】：华中科技大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：R965

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