Effect Of Lianxia Formula Granule On Cardiac Autonomic Nerve Reconstruction In Rats After Myocardial Infarction

After myocardial infarction, the cardiac sympathetic nerve and vagus nerve remodel at infarcted border zone. And this will be a keypoint to induce disorders of electrophysiology and dispersion of ventricular repolarization which can both finally induce fatal arrhythmias after myocardial infarction.And the most significant area is at the infarcted border zone where tissue repair and nerve sprouting after myocardial infarction,and nowhere is more serious than this.And it is extremely urgent for us to discuss the present situation of cardiac autonomic nerve remodeling, and decompose the existence reason, and find out a settlement method.And this paper explored the effects and mechanism of those in ways of literature summary, systematic review and experimental study.Part I:Literature summaryLiterature reviews on research progress,both at home and abroad in recent years,of sympathetic nerve remodeling after myocardial infarction and arrhythmia, nerve growth factor and cardiovascular diseases and nerve growth factor receptors have be summarized. And the latest views, latest developments and the prospective trend of development of cardiac autonomic nerve remodeling after myocardial infarction have been introduced. And unresolved problems at present have been preliminarily discussed also.Part II:Systematic ReviewObjective:To evaluate the efficacy of huanglian wendan decoction in treatment of arrhythmia.Methods:Randomized controlled trials(RCT)of the efficacy of huanglian wendan decoction in treatment of arrhythmia were collected completely and sieved according to the inclusion criteria. All the dada were analyzed with STATA11.0 software.Results:The curative effect of huanglian wendan decoction in treatment of arrhythmia was better than control groups. In the total effective rate of comprehensive curative effect[RR=1.267,95%CI:1.157-1.386, P=0.000],significant efficiency of comprehensive curative effect[RR=1.340,95%CI:1.111-1.616, P=0.002],total effective rate of clinical symptoms[RR=1.238,95%CI:1.015-1.510, P=0.035]and ECG[RR=1.256,95%CI: 1.003-1.573, P=0.047].Conclusion:Systematic review indicates that huanglian wendan decoction can improve symptoms of arrhythmia, however, further and multi-centre randomized double-blind control trials using huanglian wendan decoction are still needed because of the limited quality of the included studies.Part III:Experimental StudyObjective:To investigate the effects and mechanism of LianXia Formula Granule(LXFG) on TH mRNA,AchE mRNA,NGF mRNA,TrKA mRNA,SH2B mRNA,Erkl/2 mRNA and TH,AchE,NGF,TrKA,p-TrkA,SH2B,Erkl/2,p-Erkl/2 expression level at infarcted border zone of rats after myocardial infarction.Methods:One hundred and five healthy adult male Wistar rats were randomly assigned to seven groups:normal group, sham operated group, model group, metoprolol group,189.00 mg/kg-dose of LXFG group(high-dose group),94.50 mg/kg-dose of LXFG group(middle-dose group) and 47.25 mg/kg-dose of LXFG group(low-dose group),and fifteen rats in one group.The sham operated rats were not ligated in the left anterior descending coronary artery except metoprolol group, LXFG high-dose group, LXFG middle-dose group and LXFG low-dose group.And normal group rats didnot accept any operation.The normal group, sham operated group and model group were given with normal saline by intragastric administration, and the rest groups were given with medicine for testing by intragastric administration.Thirty days later, rats of all groups were anesthetized and plenty of their myocardial tissue at the same place of infarcted border zone was collected on the ice pack. TH mRNA, AchE mRNA, NGF mRNA, TrKA mRNA,SH2B mRNA,Erkl/2 mRNA expression level in myocardial tissue were separately measured in all groups with Real Time PCR. And TH, AchE, NGF, TrKA, p-TrkA, SH2B, Erkl/2, p-Erkl/2 expression level in myocardial tissue were separately measured in all groups with Western Blot.Results: ① Effects of LXFG on TH mRNA of Rats after AMI:Compared with the normal group and sham operated group, TH mRNA expression level in myocardial tissue at infarcted border zone of rats after myocardial infarction in the model group obviously increased(P<0.05). After treatment, compared with the model group, TH mRNA expression level in the metoprolol group,189.00 mg/kg-dose of LXFG group,94.50 mg/kg-dose of LXFG group,47.25 mg/kg-dose of LXFG group obviously decreased (P<0.05).Compared with the metoprolol group, TH mRNA expression level in the 189.00 mg/kg-dose of LXFG group obviously decreased (P<0.05). ② Effects of LXFG on AchE mRNA of Rats after AMI:Compared with the normal group and sham operated group, AchE mRNA expression level in myocardial tissue at infarcted border zone of rats after myocardial infarction in the model group significantly increased (P<0.01).After treatment, compared with the model group, AchE mRNA expression level in the metoprolol group did not obviously decrease (P >0.05) but significantly decreased (P<0.01) in 189.00 mg/kg-dose of LXFG group,94.50 mg/kg-dose of LXFG group,47.25 mg/kg-dose of LXFG group. Compared with the metoprolol group, AchE mRNA expression level in the 189.00 mg/kg-dose of LXFG group significantly decreased (P<0.01) and obviously decreased (P<0.05) in the 94.50 mg/kg-dose of LXFG group. ③ Effects of LXFG on NGF mRNA of Rats after AMI: Compared with the normal group and sham operated group, NGF mRNA expression level in myocardial tissue at infarcted border zone of rats after myocardial infarction in the model group significantly increased (P<0.01). After treatment, compared with the model group, NGF mRNA expression level in the metoprolol group,189.00 mg/kg-dose of LXFG group,94.50 mg/kg-dose of LXFG group,47.25 mg/kg-dose of LXFG group significantly decreased (P<0.01).Compared with the metoprolol group, NGF mRNA expression level in the 189.00 mg/kg-dose of LXFG group obviously decreased (P< 0.05). ④ Effects of LXFG on TrKA mRNA of Rats after AMI:Compared with the normal group and sham operated group, TrKA mRNA expression level in myocardial tissue at infarcted border zone of rats after myocardial infarction in the model group significantly increased (P< 0.01). After treatment, compared with the model group, TrKA mRNA expression level in the metoprolol group,189.00 mg/kg-dose of LXFG group,94.50 mg/kg-dose of LXFG group significantly decreased (P<0.01).Compared with the metoprolol group, there were no obvious differences among the metoprolol group and 189.00 mg/kg-dose of LXFG group and 94.50 mg/kg-dose of LXFG group (p>0.05). ⑤ Effects of LXFG on SH2B mRNA of Rats after AMI: Compared with the normal group and sham operated group, SH2B mRNA expression level in myocardial tissue at infarcted border zone of rats after myocardial infarction in the model group significantly increased (P<0.01). After treatment, compared with the model group, SH2B mRNA expression level in the metoprolol group,189.00 mg/kg-dose of LXFG group,94.50 mg/kg-dose of LXFG group,47.25 mg/kg-dose of LXFG group significantly decreased (P<0.01).Compared with the metoprolol group, SH2B mRNA expression level in the 189.00 mg/kg-dose of LXFG group obviously decreased (P< 0.05). ⑥ Effects of LXFG on Erkl/2 mRNA of Rats after AMI:Compared with the normal group and sham operated group, Erkl/2 mRNA expression level in myocardial tissue at infarcted border zone of rats after myocardial infarction in the model group significantly increased (P<0.01). After treatment, compared with the model group, Erkl/2 mRNA expression level in the metoprolol group,189.00 mg/kg-dose of LXFG group,94.50 mg/kg-dose of LXFG group significantly decreased (P<0.01). Compared with the metoprolol group, Erk1/2 mRNA expression level in the 189.00 mg/kg-dose of LXFG group significantly decreased (P<0.01). ⑦ Effects of LXFG on TH of Rats after AMI:Compared with the normal group and sham operated group, TH expression level in myocardial tissue at infarcted border zone of rats after myocardial infarction in the model group obviously increased (P<0.05). After treatment, compared with the model group, TH expression level in the metoprolol group obviously decreased (P<0.05) and significantly decreased (P<0.01) in 189.00 mg/kg-dose of LXFG group. Compared with the metoprolol group, there were no obvious differences between metoprolol group and 189.00 mg/kg-dose of LXFG group (p>0.05). ⑧ Effects of LXFG on AchE of Rats after AMI:Compared with the normal group and sham operated group, AchE expression level in myocardial tissue at infarcted border zone of rats after myocardial infarction in the model group obviously increased(P<0.05). After treatment, compared with the model group, AchE expression level in the metoprolol group did not obviously decrease (P>0.05) but obviously decreased (P<0.05) in 189.00 mg/kg-dose of LXFG group and 94.50 mg/kg-dose of LXFG group. Compared with the metoprolol group, AchE expression level in 189.00 mg/kg-dose of LXFG group obviously decreased(P<0.05). ⑨ Effects of LXFG on NGF of Rats after AMI: Compared with the normal group and sham operated group, NGF expression level in myocardial tissue at infarcted border zone of rats after myocardial infarction in the model group obviously increased (P<0.05). After treatment, compared with the model group, NGF expression level in the metoprolol group and 189.00 mg/kg-dose of LXFG group obviously decreased(P<0.05). Compared with the metoprolol group, there were no obvious differences between metoprolol group and 189.00 mg/kg-dose of LXFG group (p>0.05). ⑩ Effects of LXFG on TrKA of Rats after AMI:The mean value of TrKA expression level in myocardial tissue at infarcted border zone of rats after myocardial infarction in the model group was higher than any other groups. After treatment, all the mean value of TrKA expression level in metoprolol group,189.00 mg/kg-dose of LXFG group,94.50 mg/kg-dose of LXFG group,47.25 mg/kg-dose of LXFG group were lower than the model group. 11 Effects of LXFG on p-TrKA of Rats after AMI:Compared with the normal group and sham operated group, p-TrKA expression level in myocardial tissue at infarcted border zone of rats after myocardial infarction in the model group significantly increased(P<0.01). After treatment, compared with the model group, p-TrKA expression level in the metoprolol group,189.00 mg/kg-dose of LXFG group,94.50 mg/kg-dose of LXFG group significantly decreased (P< 0.01). Compared with the metoprolol group, p-TrKA expression level in the 189.00 mg/kg-dose of LXFG group significantly decreased (P<0.01).12 Effects of LXFG on SH2B of Rats after AMI:Compared with the normal group and sham operated group, SH2B expression level in myocardial tissue at infarcted border zone of rats after myocardial infarction in the model group obviously increased (P<0.05). After treatment, compared with the model group, SH2B expression level in the metoprolol group and 94.50 mg/kg-dose of LXFG group obviously decreased (P<0.05). Compared with the metoprolol group, there were no obvious differences between metoprolol group and 94.50 mg/kg-dose of LXFG group (p>0.05).13 Effects of LXFG on Erk1/2 of Rats after AMI:Compared with the normal group and sham operated group, Erk1/2 expression level in myocardial tissue at infarcted border zone of rats after myocardial infarction in the model group obviously increased (P<0.05). After treatment, compared with the model group, Erkl/2 expression level in the metoprolol group and 94.50 mg/kg-dose of LXFG group and 47.25 mg/kg-dose of LXFG group obviously decreased (P<0.05). Compared with the metoprolol group, there were no obvious differences among metoprolol group and 94.50 mg/kg-dose of LXFG group and 47.25 mg/kg-dose of LXFG group (p>0.05).(?) Effects of LXFG on p-Erk1/2 of Rats after AMI:Compared with the normal group and sham operated group, p-Erk1/2 expression level in myocardial tissue at infarcted border zone of rats after myocardial infarction in the model group obviously increased(P<0.05). After treatment, compared with the model group, p-Erkl/2 expression level in the metoprolol group obviously decreased (P<0.05) and significantly decreased (P<0.01) in the 47.25 mg/kg-dose of LXFG group. Compared with the metoprolol group, there were no obvious differences between metoprolol group and 47.25 mg/kg-dose of LXFG group (p>0.05)Conclusion:① Animal model of acute myocardial infarction induced by ligating the left anterior descending branch of coronary artery is a desirable animal model for researching cardiac autonomic nerve remodeling at infarcted border zone of rats,where the expression level of TH and AchE increase and the nerve sprouting or neurogenesis of cardiac sympathetic nerve and vagus nerve come out after myocardial infarction. ② Metoprolol can inhibite the cardiac sympathetic nerve remodeling at infarcted border zone of rats after myocardial infarction but the cardiac vagus nerve remodeling. And LianXia Formula Granule can both do inhibite the cardiac sympathetic nerve remodeling and cardiac vagus nerve remodeling at infarcted border zone of rats after myocardial infarction. ③ Up-regulated expression of NGF at infarcted border zone of rats after myocardial infarction gives rise to the overexpression of TrKA and SH2B, and then lead to the the overexpression of Erkl/2, and result in the overexpression of TH and AchE to promote the nerve sprouting or neurogenesis of cardiac sympathetic nerve and vagus nerve at infarcted border zone after myocardial infarction, and ultimately result in cardiac autonomic nerve remodeling. And this process maybe is one of the mechanisms of cardiac autonomic nerve remodeling at infarcted border zone after myocardial infarction. ④ LianXia Formula Granule can inhibite the up-regulated expression of NGF at infarcted border zone of rats after myocardial infarction, and decrease the expression level of TrKA and SH2B, and reduce the overexpression of Erkl/2, that is to say, LianXia Formula Granule can inhibite the expression level of the key kinases in NGF/TrKA signaling pathway regulated by NGF, and result in the down-regulated expression level of TH and AchE to cut down the nerve sprouting or neurogenesis of cardiac sympathetic nerve and vagus nerve at infarcted border zone after myocardial infarction, and ultimately inhibite the progression of cardiac autonomic nerve remodeling.