Effects Of Immunization With Synthesizal Receptor Peptide On In Vivo Pulmonary Activity In Rats

Objective:To establish the immunization model with synthetic peptides corresponding to the sequence of the second extracellular loop of M₃-muscarinic receptor and study the effect of autoantibodies against M₃-muscarinic receptor on in vivo pulmonary activity in rats.It was investigated the role of autoantibodies against M₃-muscarinic receptor in the pathogenesis of chronic obstructive pulmonary disease.Methods:(1)To establish the control and immunization models for 12 weeks.(2)To detect the rate of positive of autoantibodies against M₃-muscarinic receptor and the titer of autoantibodies in the sera.(3)To determine pulmonary function and blood gas analysis on the day next finishing immunization.(4)To observe the tissues of lung by light microscopy.Results:(1)In immunization group,the rate of positive of autoantibodies against M₃-muscarinic receptor were 100%,the geometric means of autoantibody were 1:152.There was a significant difference between the immunization group and the control group(p＜0.001). (2)The inspiratory resitance(Ri)was 1.77±0.22(cmH₂O/ml.sec)and 1.39±0.21(cmH₂O/ml.sec) in immunization and control group,respectively,it was increased,while the lung compliance(Cl) and percentage of forced expiratory volume in first 0.3 second to forced vital capacity (FEV_0.3/FVC%)were decreased in immunization group.There was a significant difference compared with the control group(p＜0.01).(3)In immunization group,the PaCO₂ was higher and the PH as well as the PaO₂ were lower that these of the control group.The values of blood gas analysis showed a significant difference between the immunization group and the control group (p＜0.01).(4)lung tissues were severely destroyed in immunization group.There were many inflammation cells and hyperplasia glands,alveolar septum changed more thicked and pulmonary alveoli expanded even formed bullae lung.(5)Positive correction were existed between autoantibodies against M₃-muscarinic receptor and pulmonary function as well as blood gas analysis in immunization group.Conclusion:The changes of pathology and lung function of the immunization mode established with synthetic peptides corresponding to the sequence of the second extracellular loop of M₃-muscarinic receptor 1 is as the same as the changes of chronic obstructive pulmonary disease in patients.The autoantibodies against M₃-muscarinic receptor maybe play a important role in the pathyogenisis of chronic obstructive pulmonary disease.