RESUMEN
Objective To establish the immunization model with synthetic M3-muscarinic receptor peptides in rats and investigate the role of autoantibodies against M3-muscarinic receptor in the pathogenesis of chronic obstructive pulmonary disease. Methods The control and immunization models were established. The rate of positive of autoantibodies against M3-muscarinic receptor and the pulmonary function were detected. The blood gas analysis was also detected on the next day after finishing immunization. The tissues of lung were observed by light microscope. Results 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 statistical difference between the immunization group and control group (x2 =6. 68, P ＜0. 01). The inspiratory resistance (Ri) was [ ( 1. 77 ±0. 22) cm H2O/ml. sec] and [ ( 1.39±0. 21 )cmH2O/ml. sec] in immunization and control group, respectively. It was increased while the lung compliance (C1) and the percentage of forced expiratory volume in first 0. 3 second to forced vital capacity ( FEV0. 3/FVC% ) were decreased in immunization group. There was a statistical difference compared with control group ( t = 3. 11,2. 82,3.23, allP ＜ 0. 01 ). In immunization group, the PaCO2 was higher and the pH as well as the PaO2 were lower than that in control group. The values of blood gas analysis showed a statistical difference between the immunization group and control group ( t =3.86,3. 47 ,allP ＜0. 01 ). Lung tissueswere severely destroyed in immunization group. There were many inflammation cells and hyperplasia glands,alveolar septum was very thick, and part of pulmonary alveoli even expanded to form bullae lung. Positive correction were found between autoantibodies against M3-muscarinic receptor and pulmonary function as well as blood gas analysis in immunization group. Conclusion The autoantibodies against M3-muscarinic receptor maybe play an important role in the pathogenesis of chronic obstructive pulmonary disease.