RESUMO
OBJECTIVE: To determine the protective role of irisin in attenuating nicotine-induced oxidative stress in vascular tissue in mice. STUDY DESIGN: Experimental study. PLACE AND DURATION OF STUDY: Foundation University, Islamabad, Pakistan, from January 2019 to June 2020. METHODOLOGY: Thirty healthy BALB/c mice were divided into 3 groups. Group 1 was control, group II received nicotine 2 mg/Kg body weight intraperitoneally for 28 days, and group III, in addition, received r-irisin 0.5 µg/g body weight /day via tail vein, for the last 14 days. The tissue anti-oxidant enzymes (SOD, CAT, and GR) and lipid peroxidation marker (TBARS) were estimated. Aortic endothelium was analysed for atherosclerotic changes. The significant difference across groups was calculated using ANOVA. RESULTS: Group II showed statistically significant increase in lipid peroxidation marker (TBARS) levels (1059.04±32.31 ng/ml, p<0.001) and reduction in anti-oxidative enzymes (SOD, CAT and GR) levels (5479.24±25.38 pg/ml, 11.51±0.24 ng/ml and 1924.88±31.23 ng/ml, p<0.001) in aortic tissue homogenate as compared to group I. In Group III, with co- administration of r-irisin, significant improvement in antioxidant enzymes i.e. SOD, CAT, and GR levels (7958.70±110.54 pg/ml, 20.86±0.57 ng/ml, and 2897.18±52.93 ng/ml) and reduction in TBARS levels (239.14±19.90 ng/ml) was observed as compared to Group II (p<0.001). Endothelial damage manifested to type IV on histological examination. Co-administration of r-irisin in group III showed significant improvement in histological grading (only Type I and II lesions were seen). CONCLUSION: Exogenous administration of irisin improves anti-oxidant enzyme levels, ameliorates nicotine-induced oxidative stress, and endothelial dysfunction in the BALB/c mice. KEY WORDS: Irisin/FNDC-5, Oxidative stress, Anti-oxidant enzymes, Endothelial dysfunction, Atherosclerosis.