[The changes and significance of interleukin-17 in rat models of chronic obstructive pulmonary disease and asthma].

OBJECTIVE

To investigate the changes of interleukin-17 (IL-17) both in rat models of chronic obstructive pulmonary disease (COPD) and in asthma.

METHODS

Male SD rats were randomly divided into COPD group, asthma group, smoking group and control group. The concentrations of IL-17 in lung tissues and in bronchoalveolar lavage fluid (BALF) were measured by enzyme-linked immunosorbent assay (ELISA). The expression of IL-17 in lung tissue was determined by immunohistochemical staining and photographic analysis.

RESULTS

The concentrations of IL-17 both in the lung tissue and in the BALF were significantly higher in the COPD group and the asthma group than in the controls and the smoking group (all P <0. 01). IL-17 was mainly expressed in airway epithelial cells of COPD rats and in T lymphocytes around the airway in rats with asthma. The levels of IL-17 were also higher both in the COPD group and in the asthma group than in the smoking group and the controls (all P < 0. 01) evaluated by immunohistochemical staining and photographic analysis. In the COPD group,IL-17 concentration of lung tissue was positively correlated with percentage of neutrophils in BALF; it also tended to be positively correlated with the level of intercellular adhesion molecule-1 (ICAM-1) in airway epithelial cells, and the concentration of IL-17 in BALF was positively correlated with the degree of smooth muscle proliferation as well. The concentration of IL-17 in the lung tissue of the asthma group was positively correlated with the number of eosinophils in BALF and with the number of CD3 T lymphocytes in lung tissues respectively.

CONCLUSIONS

The production of IL-17 in COPD and in asthma might be distinct. IL-17 probably recruits neutrophils into airways by enhancing the expression of ICAM-1 in airway epithelial cells, and it might play a role in pathological changes of small airways in COPD. The role of IL-17 in asthma maybe associated with the recruitment of eosinophils into airways.