The results of the present study revealed decreased SOD activity in the pulmonary tissues in groups M, N, and D, indicating that the pulmonary tissues in the COPD rats had a reduced ability to locally destroy the free radicals generated by various oxidative reactions and a reduced antioxidant capacity, resulting in an oxidative/antioxidant imbalance. The gene discussed is SOD1; the disease is chronic obstructive pulmonary disease.