The Activation Mechanism Of CRH Neurons In The Hypothalamic Paraventricular Nucleus Of Rats With Chronic Congestive Heart Failure And The Study Of Qiliqiangxin Capsule Intervention Effect

ABSTRACTObjective: Guided by the theory of TCM, the chronic congestive heart failure(CHF)animal model in SD,Lewis and Fisher344 rats will be established by left anterior descending branch ligation of coronary and intervened by the Chinese herb Qiliqiangxin capsule. The purpose is to discuss the relationship among activation of hypothalamic paraventricular nucleus(PVN) corticotropin releasing hormone(CRH) neurons, enhancement of the sympathetic activity, hemodynamic changes and ventricular remodeling, and to observe therapeutic effect of traditional Chinese medicine of Qiliqiangxin capsule and its possible mechanism.Methods: The study includes three sections:1 The establishment of chronic congestive heart failure(CHF) model in rat and the study of CRH neurons activation in the hypothalamic paraventricular nucleusLewis, Fisher344 and SD rats was considered as the research objects. The left anterior descending coronary artery was ligated to cause the acute cardiac muscle infarction and cardiac failure of the rat. The rats were divided into SD normal control group(control),SD sham-operated group(sham) and SD model group(model), Lewis group, and Fisher344 group.There were 5 groups in total, and 15 rats in each group. 4 weeks after the administration, the rats, biological characterization were observed and the haemodynamics of each group of rats were determined. The content of brain natriuretic peptide(BNP), angiotensin II(Ang II), norepinephrine(NE), adrenocorticotropic hormone(ACTH) and prostaglandin E2(PGE2) in blood of each group of rats was tested. The expression level of CRH neurons of the hypothalamus and ACTH neurons of the hypophysis were compared, and the activation mechanism of CRH neurons of the hypothalamus of rats suffering from heart failure was discussed about.2 The intervention effect of Qiliqiangxin Capsule administered through the lateral ventricle on cardiac function and ventricular remodeling of rat model suffering from the heart failureSD rats were considered as the research objects. The left anterior descending coronary artery was ligated to cause the acute cardiac muscle infarction and cardiac failure of the rat. The SD rats were divided into normal control group(Control), sham-operated group(Sham), model group(Model), αlpha-helical corticotrophin releasing hormone group(αh-CRH), Qiliqiangxin low dose solution group(QLRY-L) and Qiliqiangxin high dose solution group( QLRY-H), and there were 6 groups in total, and 15 rats in each group. 4 weeks after the administration, αh-CRH group were administered αlpha-helical corticotrophin releasing hormone, and QLRY-L group, QLRY-H group were administered Qiliqiangxin solution through the lateral ventricle.The normal control group, sham-operated group, model group were administered artificial cerebrospinal fluid(a CSF) by the same means. 4 weeks after the administration, the haemodynamics of each group of rats were determined, heart was HE stained and the heart weight index, lung weight index, infarction area weight/ heart weight were texted. The intervention effect of Qiliqiangxin Capsule administered through the lateral ventricle on cardiac function and ventricular remodeling of rat model suffering from the heart failure was observed.3 Related mechanism of the activation of CRH neurons of paraventricular nucleus of hypothalamus of rats suffering from chronic heart failure and the intervention effect of Qiliqiangxin CapsuleThe experimental group, the mold method and administration method were same with the second part. 4 weeks after the administration, the expression level of CRH m RNA, tumor necrosis factor-αlpha(TNF-α) m RNA, and neuronal nitricoxide synthase(n NOS) m RNA of the hypothalamus and ACTH m RNA of the hypophysis were compared. The content of NE, 5-hydroxytryptamine(5-HT) in the hypothalamus and PGE2, NE, ACTH in blood was tested by ELISA. Finally the intervention effect and mechanism of Qiliqiangxin Capsule on rats suffering from heart failure was discussed about. The correlation of the activation of CRH neurons of heart failure and the relationship with excessive activation of sympathetic nerve was explained.Results: 1 The establishment of chronic congestive heart failure(CHF) model in rat and the study of CRH neurons activation in the hypothalamic paraventricular nucleus 1.1 Observation of biological characterization of each group of ratsThe rats in the control Group and sham-operated group were lively and active. They had bright hair and the response was sensitive; the rats in the model group were tired and lazy. Some rats’ hair was yellow, not bright, and even fall off.The action against the attack reduced or disappeared; The Lewis rats have slightly slow response, their hair were yellow, not bright and their locomotor activity was reduced;and the Fisher344 rats were more tired and lazy. They had symptoms such as shortness of breath and low energy. Their hair was yellow, not bright, and fall off. They had low energy, and the action against the attack disappeared. 1.2 The determination results of hemodynamics of rats in different groupsCompared with Lewis group, LVSP and ±dp/dtmax of the Fisher344 group were significantly decreased,and LVEDP was significantly increased(P<0.01); Compared with sham-operated group, LVSP and ±dp/dtmax of the model group were significantly decreased,and LVEDP was significantly increased(P<0.01); Compared with model group, LVSP and-dp/dtmax of Lewis group were increased,and LVEDP was reduced,and LVSP, ±dp/dtmax of Fisher344 group were reduced, and LVEDP was increased(P<0.05,P<0.01). 1.3 The change of content of BNP、AngⅡ、NE、ACTH and PGE2 in blood of rats in different groupsCompared with Lewis group, BNP、AngⅡ、NE、ACTH and PGE2 in the blood of the Fisher344 group were significantlyincreased(P<0.01); Compared with sham-operated group, BNP、AngⅡ、NE、ACTH and PGE2 in the blood of the model group were significantly increased(P<0.01); Compared with model group,BNP、ACTH and PGE2 in the blood of Lewis group were reduced,and all the indexes in the blood of Fisher344 group were increased(P<0.05,P<0.01). 1.4 The change of the expression level of CRH neurons of the hypothalamus and ACTH neurons of the hypophysisCompared with Lewis group, the expression level of CRHm RNA and ACTH m RNA of Fisher344 group were obviously improved(P<0.01); Compared with sham-operated group, the expression level of CRHm RNA and ACTH m RNA of model group were obviously improved(P<0.01); Compared with model group, the two indexes of Lewis group were reduced,and the two indexes of Fisher344 group were increased(P<0.05,P<0.01). 2 The intervention effect of Qiliqiangxin Capsule administered through the lateral ventricle on cardiac function and ventricular remodeling of rat model suffering from the heart failure 2.1 The determination results of hemodynamics of rats in different groupsCompared with the sham-operated group, LVSP and ±dp/dtmax of the model group were reduced obviousely,and LVEDP was increased remarkably(P<0.01).Compared to the model group, ±dp/dtmax of all the administration groups were significantly increased, LVEDP was significantly reduced, and LVSP of αh-CRH group and QLRY-H group was significantly increased(P<0.01). 2.2 Morphological observation of cardiac muscle tissue:The normal group and sham-operated group had normal cardiac muscle tissue. The cardiac muscle fibrosis and inflammatory cell infiltration was not seen. The model group had severe cardiac muscle fibrosis and a large number of inflammatory cell infiltration. Each administration group had different degree of inhibition of cardiac muscle fibrosis, and inflammatory cell infiltration was relieved. 2.3 Results of heart weight index, lung weight index and infarction area weight/ heart weight of rats of each group:Compared with the sham-operated group, the heart weight index, lung weight index and infarction area weight/ heart weight of model group increased obviously(P<0.01). Compared to the model group,all the indexes of αh-CRH group and QLRY-H group can be reduced to varying degrees; and The heart weight index and infarction area weight/ heart weight of QLRY-L group was reduced(P<0.05,P<0.01). 3 Related mechanism of the activation of CRH neurons of paraventricular nucleus of hypothalamus of rats suffering from chronic heart failure and the intervention effect of Qiliqiangxin Capsule 3.1The change of m RNA expression level of CRH、TNF-α、n NOS of hypothalamus and ACTH of hypophysis of rats of each groupCompared with the sham-operated group, the m RNA expression level of CRH、TNF-α、ACTH significantly increased,and the m RNA expression level of n NOS significantly decreased in model group(P<0.01).Compared with the model group, the expression level of CRH、TNF-α、ACTH obviously decreased,and n NOS increased in all the administration groups,and the change of αh-CRH group and QLRY-H group was especially remarkable(P<0.05,P<0.01). 3.2 The change of NE, 5-HT content in the hypothalamic of rats in each groupCompared with the sham-operated group, the NE, 5-HT content in the hypothalamic of model rats were remarkably increased(P<0.01).Compared with the model group, the NE, 5-HT content in the hypothalamic of all the administration groups were remarkably decreased(P<0.01). 3.3 The change of plasma BNP、NE、ACTH、PGE2 content of rats in each groupCompared with the sham-operated group, the plasma BNP、NE、ACTH、PGE2 content of model rats were remarkably increased(P<0.01).Compared with the model group, the plasma BNP、NE、ACTH、PGE2 content of all the administration groups were decreased, and the change of αh-CRH group and QLRY-H group was especially remarkable(P<0.05,P<0.01).Conclusion:1 By comparison of SD rats, Lewis rats and Fisher344 rats, these results indicated that CRH neurons activation in PVN, and sympathetic activity and expression of inflammatory factors promoted by the activation of CRH neurons involved in the progression of heart failure.2 Research showed that Chinese medicine Qiliqiangxin capsule by intraventricular administration could significantly improve the hemodynamics in rats with heart failure, and inhibit ventricular remodeling, protect the heart and delay the progression of heart failure.These results showed that Qiliqiangxin capsule can intervene with the process of heart failure by acting on PVN.3 The study demonstrated that the CRH activation of paraventricular nucleus of hypothalamus in heart failure rats and the mechanism on affecting the heart failure were related to inflammatory factors and an increase in the expression of neurotransmitter release. Qiliqiangxin capsule can inhibit the related factors.