The Effect of Curcumin on Carbon Tetrachloride-Induced Lung Injury

Background/Objectives: Carbon tetrachloride (CCl₄) is a potent toxic agent that induces oxidative stress, inflammation, fibrosis, and apoptosis in various tissues, including the lungs. This study aimed to investigate the potential protective effects of curcumin against CCl₄-induced lung injury in rats using histopathological, biochemical, and immunohistochemical analyses. Methods: A total of 40 male Wistar albino rats were allocated to four experimental groups: control, curcumin, CCl₄, and CCl₄ + Cur. Curcumin was administered orally at 200 mg/kg/day for three weeks, whereas CCl₄ was administered intraperitoneally at 0.5 mL/kg as a 1:1 mixture with olive oil every other day for three weeks. Results: Histopathological examination revealed marked alveolar septal thickening, hemorrhage, vasocongestion, inflammatory cell infiltration, vacuolization, and epithelial desquamation in the CCl₄ group, whereas lung tissue architecture was largely preserved in the CCl₄ + Cur group. Biochemically, CCl₄ exposure significantly increased the MDA levels and decreased SOD activity, while curcumin administration significantly reduced the MDA levels and increased SOD activity. Immunohistochemical H-score analysis showed significantly higher TNF-α, IL-1β, TGF-β, and caspase-3 immunoreactivity in the CCl₄ group, whereas these alterations were significantly reduced following curcumin administration. Conclusions: These findings indicate that curcumin attenuated pulmonary histopathological, biochemical, and immunohistochemical alterations associated with CCl₄ exposure, accompanied by improved oxidant-antioxidant balance and reduced inflammatory, profibrotic, and apoptotic immunoreactivity. However, because hepatic injury was not evaluated, the relative contributions of direct pulmonary effects and indirect liver-mediated systemic effects could not be determined.