N-(2-mercaptopropionyl)-glycine but not Allopurinol prevented cigarette smoke-induced alveolar enlargement in mouse

We investigated the possible protective effects of the Allopurinol (A), N-(2-mercaptopropionyl)-glycine (M) and N-acetylcysteine (N) against lung injury caused by long-term exposure to cigarette smoke (CS) in mouse. C57BL6 mice were exposed to 12 cigarettes a day for 60 days and concomitantly treated with either one of the antioxidant drugs diluted in saline (CS + A-50 mg/kg; CS + M-200 mg/kg/day; CS + N-200 mg/kg/day). Control groups were sham-smoked (AA). Long-term CS exposure results in extensive parenchyma destruction in CS group. Both CS + N and CS + M groups showed preserved alveolar structure and showed preserved lung function when compared to CS group. Macrophage and neutrophil counts were decreased in CS + M, and CS + N groups when compared to CS group (p < 0.05). Antioxidant enzyme activities were reduced in all treated groups. CS + A showed the highest reduction in catalase activity (−25%, p < 0.01). We conclude that M treatment reduced long-term CS-induced inflammatory lung parenchyma destruction and lung function, comparable to N treatment, however, antioxidant administration did not reverse CS-induced antioxidant enzyme activity reduction.