Biochemical and Molecular Studies on the Effects of Heavy Tobacco and Marijuana Smoking

Abstract

The study aimed to determine leukocyte telomere length and oxidative stress in heavytobacco and marijuana smokers. It was carried out on 90 male persons divided into three groups. Group I composed of 30 non smokers, group II comprised 30 tobacco smokers and group III included 30 tobacco and marijuana smokers.The following parameters were estimated: the leukocyte telomere length using qPCR-based technique,oxidative markers like malondialdehyde (MDA) spectrophotometrically, the total antioxidant capacity (TAC) spectrophotometrically, levels of the urinary 8OHdG as a biomarker of oxidative DNA damage using HPLC, cotinine as a biomarker of tobacco smoking by ELISA and tetrahydrocannibinol (THC) as a biomarker of marijuana smokingusing enzyme immunoassay method.A highly statistically significant difference was foundbetween the three groups regarding the LTL(P-value <0.001). MDA and urinary 8HdG levels were significantly increased in groups II and III compared to the control one(P-value <0.001). On the other hand leukocyte telomere length and the level of total antioxidant capacity (TAC) were significantly decreased in groupsII&III as compared to the control (P-value <0.001). In addition, significant negative correlations were detected between the LTL and levels of MDA & urinary 8HdG in groups II and III as compared to control group while; LTL was positively correlated with TAC. In conclusion, telomere length erosion was greatly accelerated by tobacco and marijuana addiction. Oxidative stress due to heavy smoking of either tobacco or marijuana plays a key role in DNA damage and shortening of telomere length. These findings may help toexplainthe serious effects of tobacco and marijuana addiction on health.

Keywords: leukocyte telomere length, cotinine, Delta-9-tetrahydrocannabinol, oxidative stress.