Effects of N-acetylcysteine on oxidative stress and the expression of p22phox in lung tissue of diabetic rats

Objective To observe the changes of oxidative stress and the expression of p22phox,a membrane subunit of Nicotinamide Adenine Dinucleotide Phosphate-oxidase(NADPH), and effects of the antioxidant N-acetylcysteine(NAC) in the lung tissue of diabetic rats. Methods A total of 18 male SD rats (220-250 g) were randomly divided into normal control group (group C,n=6), diabetic group (group D,n=6), and diabetes with NAC treated group (group (D+N),n=6) by random digital table method. After 4 weeks, the plasma and lung tissue of rats were collected for detection of the total antioxidant, free 15-F2t-isoprostane, total superoxide dismutase(SOD) activity and Catalase(CAT) activity by kits, and p22phox protein expression by Western blotting. Results Compared with C group rats,the levels of p22phox expression in lung tissues in diabetic rats significantly increased (1.25±0.18 vs 1.00±0.00,t=3.39,P<0.05).The levels of 15-F2tisoprostane in plasma and lung tissue and total antioxidant concentration in diabetic rats significantly increased(t=14.39, 8.48, 14.72,allP<0.05) as compared with that in C rats, but the total antioxidant concentration in lung tissue, and total SOD activity and CAT activity in plasma and lung tissue significantly decreased(t=22.70, 12.64, 11.39, all P<0.05).The levels of p22phox, total antioxidant, free 15-F2tisoprostane,total superoxide dismutasein lung tissue by NAC treatment for 4 weeks were significantly improved than that of D group (1.01±0.14 vs 1.25±0.18, (0.69±0.06) vs (0.41±0.03) mmol/g, (390±21) vs (505±40)pg/mg, (2.22±0.12)vs (1.84±0.05)U/mg;t=10.54,3.19,2.56,6.26,allP<0.05). All these changes were reversed or attenuated (t=8.90,6.23,2.58,6.26,10.54,1.81,7.19,all P<0.05)remarkably by NAC treatment for 4 weeks, while the CAT activity in lung tissue unexpectedly declined (t=8.65, all P<0.05). Conclusions NAC can attenuate oxidative stress in plasma and lung tissue of diabetic rats, while decrease p22phox expression levels in lung tissue. Key words: N-acetylcysteine; Diabetic lung; Oxidative stress; Nicotinamide adenine dinucleotide phosphate oxidase; p22phox