Supplementation with vitamins C and E improves mouse lung repair.

Cigarette smoke (CS) induces emphysema by tissue destruction through the production of oxidants and metalloproteinases [matrix metalloproteinases (MMPs)]. The possibility of lung repair after emphysema remains unclear. Our aim was to study the effects of vitamins C and E on mouse lung repair evaluated by catalase (CAT), superoxide dismutase (SOD) and MMP-9 activities; by the amount of tumor necrosis factor (TNF)-alpha in lung homogenates; by cell quantification in bronchoalveolar lavage (BAL) fluid; and by lung histology. Male C57BL/6 mice (n=25) were exposed to nine cigarettes per day, 7 days/week, for 60 days in a whole-body exposure chamber. The control group was sham smoked (n=10). After 60 days of CS exposure, a group of animals was sacrificed (n=5) and the others were divided into two groups: (a) CSv (n=10) supplemented with saline and olive oil (vehicles) for 60 days and (b) CSr (n=10) supplemented with vitamins C and E (50 mg/kg/day) for 60 days. These mice were then sacrificed; BAL was performed and the lungs were removed for biochemical and histological analysis. The results demonstrated that CAT activity was decreased in the CSv and CSr groups compared to the control group. SOD activity was higher in the CSv group than in the control and CSr groups. The CSv group showed a higher neutrophil count in BAL fluid, associated with more TNF-alpha in lung homogenates, than the control or CSr groups. Finally, emphysema in the CSv group was associated with fewer collagen and elastic fibers than in the control and CSr groups. These results indicate a possible role of vitamins C and E in lung repair after emphysema induced by long-term CS exposure in mice.