Abstract
Objective: To investigate the role of neurogenic inflammation in increasing cough responsiveness in respiratory syncytial virus (RSV) -infected guinea pigs
Methods: Fifty guinea pigs were randomly divided into a control group and four RSV-inoculated groups: post-infection day (PID) 6, 12, 28 and 42. cough responsiveness, airway inflammation, RSV antigen and nucleic acid, substance P (SP) protein content and expression, and neurokinin receptor 1 (NK1) mRNA expression were evaluated and the correlation between cough responsiveness and SP and NK1 mRNA levels determined.
Results: Cough responsiveness of infected groups was significantly higher than control and reached a peak at PID 12. Inflammatory cells and lymphocytes increased in bronchoalveolar lavage fluid, and lung tissue pathology showed airway inflammation without pneumonia. RSV RNA content was highest at PID 6 and then gradually decreased. SP peaked at PID 28 and remained high at PID 42, SP protein staining could be seen in lung tissue. NK1 mRNA levels were also significantly increased at PID 12, 28 and 42. cough responsiveness was positively correlated with and SP and NK1 mRNA levels.
Conclusion: The increase in cough responsiveness was consistent with the clinical features of cough caused by RSV. The accompanying increase in SP and its receptor with the positive correlation between these parameters and cough responsiveness suggests that neurogenic inflammation may play a decisive role in the increase in cough responsiveness and cough induced by RSV.
- © 2011 ERS