coadministration of calcium chloride with lead acetate can improve motility of cauda epididymal spermatozoa in swiss white mice

background: lead is an industrial heavy metal that can decrease sperm motility. objective: the aim was to investigate the protective effects of calcium against lead on motility of spermatozoa. materials and methods: in total 40 adult male swiss white mice were randomly divided into 5 groups (control, lead of 1st wk, lead of 2nd wk, lead/calcium of 1st wk and lead/calcium of 2nd wk). the lead groups of mice were injected by a single dose of lead acetate (200 mg/kg) intraperitoneally. lead/calcium groups of mice were injected by a single same dose of lead acetate along with three doses of 80 mg/kg calcium chloride. the control group of mice was injected only with same volume of distilled water through the same route. mice of 1st and 2nd wk groups were sacrificed through cervical dislocation one and two weeks after injections respectively. results: mean of the progressive motile spermatozoa of cauda epididymis in lead/calcium group of the first week was higher than the lead group of the first week and this difference was significant. there was not any significant difference among weight of testes and epididymides of all groups. conclusion: it can be concluded that calcium can decrease the effects of lead on sperm motility.