Theophylline attenuates bleomycin-induced oxidative stress in rats: The role of IL-6, NF-κB, and antioxidant enzymes

Abstract The purpose of this study was to evaluate the antifibrotic and antioxidant roles of theophylline (Theo), a bioactive compound, in bleomycin (BLM)-induced pulmonary fibrosis in Wistar albino rats. Assigned into 4 groups were 32 Wistar albino rats, comprising the control group (administered 0.9% isotonic saline), BLM group (treated with BLM at a dose of 2.5 mg/kg), BLM+Theo group (treated with Theo at a dose of 75 mg/kg + BLM at a dose of 2.5 mg/kg), and Theo group (treated with Theo at a dose of 75 mg/kg). In the BLM group, a significant decrease was observed in the catalase and glutathione peroxidase enzyme activities, and reduced glutathione (GSH) (p < 0.05, p< 0.05, p< 0.001, respectively), while the malondialdehyde (MDA) levels (p< 0.001) were significantly elevated when compared to the control group. However, the MDA levels in the BLM+Theo group were also significantly higher than in the control group (p< 0.01). Similarly, the GSH levels were significantly higher in the BLM+Theo group than in the BLM group (p< 0.05). The results indicated that Theo reduced the BLM-induced activation of nuclear factor-kappaB (NF-κB) and decreased interleukin-6 (IL-6) levels, together with significant amelioration of the immunohistochemical and histopathological architecture in the lung tissues. It was concluded that the administration of Theo had a positive effect on the GSH level, and activation of NF-κB and IL-6 expression, which were significant proinflammatory markers in the BLM-treated rats.