Objective: To observe the effects of different doses of modified Yupingfeng San on Haemophilus influenza

Klebsiella pneumoniae and Pseudomonas aeruginosa in airway of chronic obstructive pulmonary disease(COPD) rats

and provide experimental basis for the treatment of COPD by modified Yupingfeng San. Method: COPD rat models were induced by intratracheal instillation of LPS plus smoked method. The Wistar rats were randomly divided into normal group

model group

modified Yupingfeng San high dose

middle dose and low dose groups(4.644

9.288

27.864 g·kg-1·d-1)

n=10 in each group. The contents of 3 kinds of bacteria were analyzed by high-throughput sequencing method in each group

and the histopathological changes of the right lung were observed by HE staining. Result: As compared with the normal group

the contents of H. influenza

K. pneumoniae and P. aeruginosa were increased in the airway of model group mice(P<0.05); right lung pathological observation results showed increase of chronic inflammatory cells in right lungs of model group and a small amount of neutrophil infiltration. As compared with the model group

the contents of H. influenza

K. pneumoniae and P. aeruginosa were decreased in modified Yupingfeng San low dose and middle dose groups(P<0.05); the contents of the above bacteria were decreased in modified Yupingfeng San low dose

middle dose and high dose groups(P<0.05

P<0.01)

and the lesions in right lung tissues were significantly improved. Conclusion: Modified Yupingfeng San could significantly reduce the contents of H. influenza

K. pneumoniae and P. aeruginosa in airway of COPD rats

and the low dose group had more obvious effects on P. aeruginosa. This may be one of the important mechanisms for the treatment of COPD.