protective effects of famotidine and vitamin c against radiation induced cellular damage in mouse spermatogenesis process

background: radioprotective effect of famotidine was previously shown on radiation induced micronuclei and chromosomal aberrations in human peripheral lymphocytes and mouse bone marrow cells however, its radioprotective property has never been studied in mouse spermatogenesis. it was also shown that vitamin c as an antioxidant also exert its radioprotective effect on many biological systems, but in some studies no protective effect is reported. materials and methods: mice were injected by small and nontoxic amount of vitamin c and famotidine (3 and 2μg) inter-testicular 2 hours before irradiating by gamma ray. 29 days after irradiation, mice were sacrificed and testes were removed, weighed and either fixed for histological study or homogenized in 1.5 ml de-ionized water and 0.5 ml sds solution. sperm head count was done under a light microscope. survival fractions were calculated and plotted as a function of dose of gamma rays. results: the sperm head count in groups treated with vitamin c and famotidine before gamma irradiation show significant increase compared to groups only irradiated by gamma rays (p<0.01). values of calculated dose reduction factor (drf) are 2 and 2.68 for vitamin c and famotidine respectively. both vitamin c and famotidine could reduce radiation induced pathological alterations in seminiferous tubules. conclusion: these results suggest that vitamin c and famotidine have radioprotective property and could reduce cytotoxic effect of radiation in mouse spermatogenesis, one of the most radiosensitive biological systems. the possible mechanism of protection by famotidine and vitamin c might be radical scavenging. the radioprotection index for famotidine was found to be more than vitamin c. iran. j. radiat. res., 2011 8(4): 223-230