Effect Of Non-peptide Nociceptin/orphanin FQ Receptor Antagonist On Arrhythmia After Acute Myocardial Ischemia In Rats

Objective:Arrhythmia after acute myocardial ischemia is one of the causes of sudden cardiac death.Endogenous nociceptin/orphanin FQ（N/OFQ）is involved in the occurrence of arrhythmia after ischemia.Here we discuss the effects of non-peptide orphanin effects of body antagonists J-113397,SB-612111 and compound-24（C-24）on arrhythmia after acute myocardial ischemia in rats.And find their respective optimal concentration.To explore whether the mechanism of action of the three non-peptide orphaninfin receptor antagonists on arrhythmia after acute myocardial ischemia is related to the inflammatory system and the sympathetic nervous system.Methods:110 clean-grade male SD rats,6-8 weeks old,weighing 250-300g,experiment after one week of adaptive feeding.This experiment consists of two parts.Part One:The effect of non-peptide nociceptin/orphanin FQ receptor antagonist on arrhythmia and cardiac function within 15 minutes after acute myocardial ischemia in ratsA rat model of acute myocardial ischemia was prepared by ligating the left anterior descending coronary artery,and 110 rats were divided into 11 groups according to the random number table method.Divided into sham operation group（Sham group,which only opens the chest and does not ligate the coronary arteries）,the coronary artery ligation group（CAO group,which opens the chest and ligates the coronary arteries）and three non-peptide N/OFQ receptors Antagonist group（J group,S group,C group,these three groups were opened and ligated the coronary arteries.Before ligation,according to the group,the corresponding concentration of drugs was injected through the tail vein at a loading amount of 1ml/kg）.According to the concentration gradient of the antagonist,the three groups of antagonist groups are divided into three subgroups.J group（J-113397）is divided into J-Ⅰgroup(1×10^-7mol/l),J-Ⅱgroup(1×10^-9mol/l),J-Ⅲgroup(1×10^-11mol/l),S group（SB-612111）is divided into S-Ⅰgroup(1×10^-9mol/l),S-Ⅱgroup(1×10^-11mol/l),S-Ⅲgroup(1×10^-13mol/l)),C group（C-24）is divided into C-Ⅰgroup(1×10^-9mol/l),C-Ⅱgroup(1×10^-11mol/l),C-Ⅲgroup(1×10^-13mol/l)l),10 per group.After each group of rats were treated according to regulations,the number of occurrences of ventricular arrhythmia and cardiac function data within 15 minutes after acute myocardial ischemia were recorded.Part Two:The effect of non-peptide nociceptin/orphanin FQ receptor antagonists on heart rate variability and inflammatory factors in myocardial tissue within 15minutes after acute myocardial ischemiaThe first part of the experiment dynamically monitored the rat’s ECG signal within15 minutes,and used the RM6240 biological signal acquisition and processing system to analyze the heart rate variability index.All rats were sacrificed 15 minutes after coronary artery ligation.The rat myocardial tissue was ground and the supernatant was frozen and stored at-20℃.The concentration of inflammatory factors including tumor necrosis factor（TNF-α）and interleukin 1β（IL-1β）was detected by ELISA.Correlation analysis between the frequency of ventricular premature beats and the concentration of inflammatory factors TNF-αand IL-1βwithin 15 minutes after acute myocardial ischemia.Results:Part One:The effect of non-peptide nociceptin/orphanin FQ receptor antagonist on arrhythmia and cardiac function within 15 minutes after acute myocardial ischemia in ratsCompared with the Sham group,the number of VEBs in the CAO group,J group,S group and C group was significantly increased（P<0.05）;the CAO group VT+VF number,duration and arrhythmia score increased significantly（P<0.05）.The number of VT+VF and arrhythmia scores in C-Ⅲgroup increased significantly（P<0.05）,and the arrhythmia scores in J-Ⅲgroup and S-Ⅲgroup increased significantly（P<0.05）.Compared with the CAO group,the number of VEBs in the J group,S group,and C group decreased significantly（P<0.05）;the number,duration,and arrhythmia score of the C-I group decreased significantly（P<0.05）.For the comparison of the number of VEB attacks among the subgroups,compared with the J-I group,the number of VEB attacks in the J-Ⅱgroup,J-Ⅲgroup,S-Ⅲgroup,C-Ⅱgroup,and C-Ⅲgroup was significantly increased（P<0.05）.Compared with J-Ⅱgroup,J-Ⅲgroup,S-Ⅲgroup,C-Ⅲgroup increased significantly（P<0.05）,S-I group,S-Ⅱgroup,and C-I group decreased significantly（P<0.05）).Compared with the J-Ⅲgroup,the S-Ⅰgroup,S-Ⅱgroup,C-Ⅰgroup and C-Ⅱgroup were significantly reduced（P<0.05）.Compared with S-Ⅰgroup,S-Ⅲgroup and C-Ⅲgroup increased significantly（P<0.05）.Compared with S-Ⅱgroup,S-Ⅲgroup,C-Ⅱgroup,C-Ⅲgroup increased significantly（P<0.05）.Compared with group C-Ⅰ,group C-Ⅱand group C-Ⅲincreased significantly（P<0.05）.Compared with C-Ⅱgroup,C-Ⅲgroup increased significantly（P<0.05）.Compared with C-Ⅰgroup,the arrhythmia score of C-Ⅲgroup was significantly higher（P<0.05）.After coronary artery ligation,the changes in the cardiac function indexes of each group were small.Compared with the Sham group,the HR of the J-Ⅲgroup was significantly reduced（P<0.05）.However,there were no statistically significant differences in LVSP,LVEDP,+dp/dtmax H and-dp/dtmax in each group.Part Two:The effect of non-peptide nociceptin/orphanin FQ receptor antagonists on heart rate variability and inflammatory factors in myocardial tissue within 15minutes after acute myocardial ischemiaCompared with the Sham group,the SDNN and RMSSD of the CAO group,J group,S group,and C group were significantly reduced（P<0.05）.For RMSSD,compared with the CAO group,there was a significant increase in the J-Ⅱ,S-Ⅰ,S-Ⅲ,C-Ⅱ,and C-Ⅲgroups（P<0.05）.Compared with C-Ⅰgroup,S-Ⅰgroup and C-Ⅲgroup increased significantly（P<0.05）.Compared with the CAO group,the LF/HF of the J group,S group,and C group were significantly lower（P<0.05）.The other two indexes,LFnorm and HFnorm,were not statistically different in each group.Compared with the TNF-αconcentration of rats in each group,compared with the Sham group,the concentrations of TNF-αand IL-1βin the J group,S group,and C group were all significantly increased（P<0.05）.Compared with the CAO group,the concentrations of TNF-αand IL-1βin the J-Ⅰgroup,J-Ⅱgroup,S-Ⅰgroup,S-Ⅱgroup,C-Ⅰgroup and C-Ⅱgroup were significantly decreased（P<0.05）.Compared with the CAO group,the TNF-αconcentration in the J-Ⅱgroup was significantly decreased（P<0.05）.Compared with the S-Ⅱgroup,the TNF-αconcentration in the J-Ⅲgroup,S-Ⅰgroup,S-Ⅲgroup and C-Ⅲgroup increased significantly（P<0.05）.Compared with the S-Ⅱgroup,the TNF-αconcentration in the J-Ⅲgroup and the C-Ⅲgroup was significantly increased（P<0.05）;compared with the C-Ⅰgroup,the IL-1βconcentration in the C-Ⅲgroup was significantly increased（P<0.05）.Correlation analysis shows:J group:the concentration of TNF-αand IL-1βwere positively correlated（r=0.668,P<0.01）;the concentration of TNF-αwas positively correlated with the number of VEB attacks（r=0.616,P<0.01）;The concentration of IL-1βwas positively correlated with the number of VEB attacks（r=0.614,P<0.01）.S group:the concentration of TNF-αand IL-1βwere positively correlated（r=0.560,P<0.01）;the concentration of TNF-αwas positively correlated with the number of VEB attacks（r=0.634,P<0.01）;the concentration of IL-1βwas positively correlated with VEB The number of episodes was positively correlated（r=0.652,P<0.01）.C group:The concentration of TNF-αand IL-1βwere positively correlated（r=0.503,P<0.01）;the concentration of TNF-αwas positively correlated with the number of VEB attacks（r=0.485,P<0.01）;the concentration of IL-1βwas positively correlated with VEB The number of episodes was positively correlated（r=0.511,P<0.01）.Conclusion:Pretreatment with three antagonists is effective for the occurrence of arrhythmia after acute myocardial ischemia,and the concentration of TNF-αand IL-1βin myocardial tissue is significantly reduced.Their respective optimal effective concentrations are J-113397(1×10^-7mol/l),S-612111(1×10^-11mol/l)and C-24(1×10^-9mol/l).Correlation analysis results show that the mechanism of action of the three antagonists is related to the regulation of sympathetic nerve activity and the occurrence of inflammation.