M <sub> 2 </ Sub> Receptor Antibody In The Pathogenesis Of Pulmonary Heart Disease On Cardiac Function Of Experimental Research

Objective:To establish the typical model of chronic cor pulmonale and study the effect of antibodies to M2-muscarinic receptor(M2-Ab)to the cardiac function. It was deeply investigated that the effect and mechanism of antibodies to M2-muscarinic receptor to the cardiac in chronic cor pulmonale.Methods:(1) Control group were fed in normal condition. Hypoxic group in which the typical model of chronic cor pulmonale was constructed according to the method of XUE's. (2)To detect the rate of positive antibody and the titers of M2-Ab in the sera, the pulmonary artery pressure and cardiac anatomic measurements. (3)The cardiac function was observed by perfused isolated rat heart to consist of LVSP, LVDP, +dp/dtmax, -dp/dtmax, P,et al. Results: (1) In hypoxic group , the rate of positive of M2-Ab the sera were 70%. The geometric means of M2-Ab titers in hypoxic group were 1:97. There was a significant difference between the hypoxic group(70%)and the healthy control (10%,p<0.01). (2) The pulmonary artery pressure was 4.38±0.60(kPa)and 2.10±0.25(kpa),in hypoxic group and the control group, repectively. Pulmonary artery pressure in hypoxic group showed a significant difference compared with the control group(P<0.01).(3) Both the left and right ventricles were significantly enlarged in terms of cavity dimension in hypoxic group. There was a significant difference in the cavity dimansion of the both left and ventricle between the hypoxic group group and the control group(P<0.05). (4)The cardiac function: 1> M2-Ab weakened significantly the cardiac function in adose-dependent manner. At the dose of 40 nmol/L, M2-Ab decreased the LVSP-LVDP, +dp/dtmax and -dp/dtmax from the control value of 7.08±1.20(KPa),155.23±18.44(KPa/S),84.11±7.21(KPa/S)and 126±6 to 4.77±1.06(KPa),118.49±15.14(KPa/S),67.56±8.13(KPa/S)and 90±6, (all p<0.01),respectively. 2> Carb also weakened significantly the cardiac function. There was a significant difference compareing with the control group(P<0.01)and no significant difference compareing with 40 nmol/L M2-Ab. 3> M2-receptor could counteract this negative fuction of M2-Ab.Atropine could obstruct the negative fuction of M2-Ab and Carb.Conclusion: In hypoxic group, the rate of positive antibody and the titers of M2-Ab in the sera have been kept with a very high level, which experimentally indicates that there were a great relationship between the M2-Ab and the pathogenesis of chronic cor pulmonale. M2-Ab weakened significantly the cardiac function, while M2-receptor could counteract this fuction. By M2-receptor, M2-Ab maybe play a important role to the disorder of cardiac function in chronic cor pulmonale.