The Expression And Significance Of IL-4 In Bleomycin-Induced Pulmonary Fibrosis In Rats

OBJECTIVE: To detect the expression of IL-4 in bleomycin-inducedpulmonary fibrosis in rats and to study the effect of IL-4 in pulmonaryfibrosis pathogenesis. METHODS: Female wistar rats (170～190g weight) were treatedwith bleomycin(5 mg/kg weight) by intratracheal perfusion on day 0 toinduce pulmonary fibrosis, while the controlled animals received onlynormal saline (NS). The rats were killed on day 7 and 14, and lung tissueand blood serum were collected. Lung Coefficient [ lung weight (mg) /body weight (g) ] was counted at the same time. The right lung was stainedwith hematoxylin-eosin to observe the lesion of lung tissue. Reversetranscription polymerase chain reaction (RT-PCR) was used to get theexpression of IL-4mRNA in the left lung and ELISA was used to detect thelevels of IL-4 in blood serum. RESULTS: Alveolus inflammation was observed on day 7 andfibrosis focus was found on day 14. Lung Coefficient of model groupsincreased significantly. Compared with controlled group, the expressionlevels of IL-4mRNA in lung tissue and the levels of IL-4 in blood serumwere elevated significantly in model groups (P<0.05). CONCLISIONS: IL-4 may play an important role in pathogenesis ofpulmonary fibrosis, and possibly, the down-regulation of IL-4 level orantagonist of IL-4 could be taken as new direction in studying the treatmentof pulmonary fibrosis.