Radioprotective role of α-tocotrienol against oxidative damage in γ-irradiated human blood cultures

Abstract

Tocotrienols are members of the natural vitamin E family which is considered one of important fat soluble vitamins. The tocotrienols react with free radicals, which are the main cause of oxidation damage to cell membranes, without formation of other free radicals in the process.  All natural forms of tocotrienols have the ability to regulate peroxidation reactions and to control free radicals production within the body. This study aimed to assess the antimutagenic and antioxidant ability of α-tocotrienol at a working dose (0.04 mg/ ml) through cytogenetic (Micronucleus test) study and biochemical analysis including Caspase -3, Superoxide dismutase (SOD), Catalase (CAT) activities and Nitric Oxide (NO) concentration in γ-irradiated human blood cultures. The treatment time was 72 hrs post-irradiation with gamma rays at dose of 3 Gy. Triple blood cultures for each blood sample were set up. Ionizing irradiation induces a significant increase in micronuclei (MNi) frequencies, and nucleuplasmic bridge (N bridge) accompanied by a significant rise in Caspase-3 activity and NO concentration. Furthermore, SOD and CAT activities showed significant decrease. α-tocotrienol treatment results into a decrease of MNi and N bridges numbers, enhancement of SOD and CAT activities and improvement of both NO and Caspase-3 levels, compared to irradiated cells which not treated with α-tocotrienol. The present results reveal the antimutagenic and the anti-oxidant effects of α-tocotrienol against γ- irradiation.