Effect of Cigarette Smoking on Selected Antioxidant Enzymes and Oxidative Stress Biomarkers

Introduction: Cigarette Smoking (CS) is the single greatest preventable cause of disease and death and is rich in Reactive Oxygen and Nitrogen Species (ROS and RNS). These can cause the production of other free radicals, which, in turn, initiate lipid peroxidation and cause several diseases. Free radical scavenger enzymes namely Superoxide Dismutase (SOD), Catalase (CAT) and Glutathione Peroxidase (GPx) represent the enzymatic part that have the ability to inhibit oxidative stress by scavenging the highly destructive free radicals. Aim: To study the effect of CS on selected antioxidant enzymes and oxidative stress biomarkers. Materials and Methods: A case control study was conducted from September 2016 to September 2019 in which total of 284 healthy (without any systemic diseases) cigarette smokers (cases) in the age group of 18-60 years compared with age and sex matched 284 nonsmokers (controls) were included in the study. Estimation of serum 8-hydroxydeoxyguanosine (8-OHdG) by Enzyme Linked Immunosorbant Assay (ELISA), Malondialdehyde (MDA) by Thiobarbuturic Acid Reactive Substances (TBARS), SOD by water soluble tetrazolium salt 1, GPx and CAT by colorimetric method. The analysis was carried out using the SPSS 19.0.2 program for windows. Unpaired t-test and one-way ANOVA were used to analyse all the data for statistical significance. Results: The mean Serum MDA and 8-OHdG levels were significantly raised 7.47 +/- 1.84, 63.41 +/- 22.44 as compared to nonsmokers (3.90 +/- 1.03, 40.04 +/- 20.14) and serum SOD, Gpx and CAT levels were decreased 62.55 +/- 19.97, 44.45 +/- 16.60 and 12.92 +/- 10.16 in cigarette smokers as compared to nonsmokers 274.04 +/- 68.37, 208.56 +/- 75.63 and 127.82 +/- 18.68, respectively. These differences were also found to be statistically significant in cigarette smokers according to duration and number of cigarette smoked at the level of <0.05. Conclusion: In conclusion CS, especially long-term smoking may leads to significant changes in the enzymatic antioxidant defense systems of smokers. Discontinuation of smoking and general awareness needs to be created to minimise the risk of smoking related diseases.