Increased production of oxygen free radicals in cigarette smokers

Oxygen free radicals are known to produce damage in many biological tissues. Cigarette smoking is a major risk factor for various diseases. It is possible that oxygen free radical producing activity of polymorphonuclear (PMN) leucocytes is increased by cigarette smoking. We studied the oxygen free radical producing (luminol-dependent chemiluminescent) activity of PMN leucocytes in blood and the malondialdehyde (lipid peroxidation product) content of blood and serum in nonsmokers and smokers. The zymosan-induced chemiluminescent activity was measured on a LKB 1251 luminometer. The malondialdehyde (MDA) was measured as thiobarbituric acid (TBA) reactive substances. The chemiluminescent activity due to oxygen-derived free radicals (superoxide anion, hydrogen peroxide, hydroxyl radical) and superoxide dismutase (SOD)-inhibitable (superoxide anion) in nonsmokers were 1215.1 +/- 91.1 and 849.3 +/- 72.3 mV min/10(6) PMN leucocytes respectively. There was a significant increase in the oxygen-derived free radicals and SOD-inhibitable chemiluminescence in smokers. The values of blood and serum MDA were 171.7 +/- 6.1 and 222.2 +/- 5.6 nmoles/l respectively in nonsmokers. There was an increase in both blood and serum MDA in smokers. These results suggest that the increased generation of oxygen free radicals by PMN leucocytes might be responsible for an enhanced risk of various diseases related to cigarette smoking.