Abstract
This study was conducted on mice to evaluate the radioprotective role of l-carnitine against γ-ray irradiation-induced testicular damage. Adult male mice were exposed to whole body irradiation at a total dose of 1Gy. Radiation exposure was continued 24h a day (0.1Gy/day) throughout the 10 days exposure period either in the absence and/or presence of l-carnitine at an i.p. dose of 10mg/kg body weight/day. Results revealed that γ-rays irradiation suppressed the expression of ABP and CYP450SCC mRNA, whereas treatment with l-carnitine prior and throughout γ-rays irradiation exposure inhibited this suppression. Treatment with γ-ray irradiation or l-carnitine down-regulated expression of aromatase mRNA. With combined treatment, l-carnitine significantly normalized aromatase expression. γ-Ray irradiation up-regulated expression of FasL and Cyclin D2 mRNA, while l-carnitine inhibited these up-regulations. Results also showed that γ-ray-irradiation up-regulated TNF-α, IL1-β and IFN-γ mRNA expressions compared to either controls or the l-carnitine treated group. Moreover, γ-irradiation greatly reduced serum testosterone levels, while l-carnitine, either alone or in combination with irradiation, significantly increased serum testosterone levels compared to controls. In addition, γ-irradiation induced high levels of sperm abnormalities (43%) which were decreased to 12% in the presence of l-carnitine. In parallel with these findings, histological examination showed that γ-irradiation induced severe tubular degenerative changes, which were reduced by l-carnitine pre-treatment. These results clarified the immunostimulatory effects of l-carnitine and its radioprotective role against testicular injury.