Objective: To observe the role of bacterial infection in pathogenesis of COPD.
Methods: The COPD animal model was developed by intranasal repeated injecting Klebsiella pneumoniae(K) or pneumococcal pneumoniae(P) into rat respiratory tract. Histomorphyological changes were observed, PaO2, PaCO2 and right ventricular systolic pressure (RVSP) were analysed.
Results: 1 week after injecting K and 4 week after injecting P, the epithelia of bronchioles showed obvious injury. From the 4th week there was severe chronic inflammatory process of bronchioles in 2 experimental groups including thickened wall, narrowed lumen and developed emphysema. In addition, the walls of arterioles accompanying bronchioles were also thickened obviously. Right ventricular systolic pressure raised in 2 experimental groups (P < 0.01). From the 16th week, PaO2 dropped and PaCO2 raised in K group.
Conclusions: Repeated injecting intranasally of the proper amount of klebsiella pneumoniae or pneumococcal pneumoniae into rats' lungs can induce rat small airway inflammation and emphysema. Combining with PaO2, PaCO2 and RVSP analysis, we suggest the model established shows main features of COPD.