Objective: To explore the effects of wind and dampness pathogens on cytokines in the lung tissue of rats with cold syndrome due to different gradient cold pathogens.
Methods: One hundred and four Wistar rats of SPF grade were randomly divided into 13 groups: normal temperature group, six cold pathogen groups and six cold plus wind-dampness pathogen (wind of grade 5 and 90%-100% relative humidity) groups. The cold pathogens were constant low temperature (including 10 ℃, 0 ℃, –10 ℃) and temperature change (including 20 to 10 ℃, 20 to 0 ℃, and 20 to –10 ℃). The rats in different groups were kept in a temperature-controlled box under the corresponding condition for 2 hours on the first day of experiment. Then, the rats were all raised in normal temperature for 4 days and the rats' behaviors were observed. The contents of tumor necrosis factor α (TNF-α), interleukin-6(IL-6) and interleukin-4(IL-4) in lung homogenate were measured by radioimmunoassay and the content of interferon-γ (IFN-γ) was detected by enzyme-linked immunosorbent assay.
Results: In comparison with cold pathogen groups, contents of TNF-α, IL-6 and IL-4 were obviously increased in lung homogenate of rats in cold plus wind-dampness pathogen groups (P<0.01), and the content of IFN-γ and IFN-γ/IL-4 ratio were obviously decreased (P<0.01).
Conclusion: Wind-dampness pathogen can seriously aggravate the injury to lung tissue caused by cold pathogen, and the unbalance of Th₁/Th₂ in lung homogenate of rats.

Key words: pathogenic cold, pathogenic wind, pathogenic dampness, rats, pathogen-cold invading lung, cytokines