A40 Antioxidant, Anti-Inflammatory, and Antiapoptotic Potential of Curcumin in Benzo(a)pyrene (BaP)-Induced Lung Injury in Rats

Abstract

Benzo(a)pyrene (BaP) is a well-known pollutant that directly induces inflammatory microenvironment in the lung. It also enhances oxidative stress and apoptosis and interferes with several other molecular pathways including cell death, survival, and proliferation that disturb normal homeostasis of the lung. Curcumin (Cur) has potent anti-inflammatory, antioxidant activity that defends cells from oxidative stress and cell death. The objectives of the present study were to explore the protective effects of curcumin against long-term administration of BaP-induced disturbances in lungs of rats. Male rats were randomly divided into four groups: saline control, BaP only, BaP + Cur, and Cur only. Lung injury histopathology, electron microscopy, inflammatory cytokine release, antioxidant levels, apoptosis, and cell cycle were examined. Instillation of BaP significantly increased infiltration of inflammatory cells in alveolar space and inflammatory cytokine in blood. Histopathologic examination found BaP-induced pulmonary inflammatory changes were improved after administration of curcumin as evident by less infiltration of macrophages and neutrophils in alveolar space, less deposition of collagen, and edema. Furthermore, electron microscopy results also showed necrotic changes and broken cell membrane of Type II epithelial cell (T2E) of alveoli in BaP group, which was reduced after addition of curcumin treatment. In addition, we found BaP plus curcumin treatment effectively reduced inflammatory cytokines TNF-α and IL-6 in blood serum, but no significant changes were found in CRP levels. Moreover, the levels of tunnel staining and p53 expression were significantly increased by BaP, whereas these changes were noticeably modulated after curcumin treatment. Bap also interferes in normal cell cycle, which was markedly improved with curcumin treatment. Overall. these findings suggest that curcumin attenuates BaP-induced lung injury, probably through inhibiting inflammation, oxidative stress, and apoptosis in lung epithelial cells, and improving cell proliferation and antioxidants' level. Thus, curcumin may be an alternative therapy for improving the outcomes of benzo(a)pyrene-induced lung injury.