Valsartan attenuates bleomycin-induced pulmonary fibrosis by inhibition of NF-κB expression and regulation of Th1/Th2 cytokines.

OBJECTIVE

Pulmonary fibrosis (PF) is a chronic respiratory system disease. The role of inflammation and angiotensin in the development and progression of PF has previously been demonstrated. Alternation in antifibrotic/profibrotic mediators and NF-κB activation have important roles in PF development. NF-κB, a nuclear factor, induces the transcription of inflammatory and pro-inflammatory cytokines. The aim of this study was to evaluate the effect of valsartan as an angiotensin receptor blocker on IL-4, INF-γ, and NF-κB expression in the treatment of PF.

MATERIALS AND METHODS

Rats were divided into five groups: groups I (bleomycin) and II (control) received a single injection of bleomycin (7.5 IU/kg) or vehicle, respectively. Groups III-V received valsartan (20, 40, and 80 mg/kg, respectively) orally a week before and for 3 weeks after the bleomycin injection. Serum levels of IL-4 and INF- γ were then measured. Relative NF-κB expression was investigated by real-time PCR.

RESULTS

Histopathological examination showed the anti-inflammation effect of valsartan. Bleomycin significantly increased IL-4 serum level and decreased that of INF-γ in the serum. Valsartan could restore their levels to normal. Valsartan raised the decreased ratio of INF-γ/IL-4. Exposure to bleomycin elevated NF-κB expression; and valsartan decreased the increased gene expression.

DISCUSSION

Valsartan as an angiotensin receptor antagonist presumably by blocking angiotensin receptor causes to ameliorated PF, which was at least partly due to antifibrotic/profibrotic cytokine regulation and reduced NF-κB expression.

CONCLUSIONS

Valsartan showed a significant protective effect against bleomycin-induced PF.