IN VITRO EFFECTS OF COPPER ON THE MOTILITY AND VIABILITY OF SPERMATOZOA

Abstract

Copper (Cu) is an environmental risk factor which has various effects on the animal and human organism. The target of this study was to investigate the effects of Cu on motility and viability of spermatozoa in vitro. Specifically, we examined the dose- and time-dependent effect of copper (II) chloride (CuCl2) on the survival of spermatozoa during different time periods (Time 0 h, 1 h, 2 h). The percentage of motile spermatozoa was determined after exposure to concentrations of 3.9; 7.8; 15.6; 31.2; 62.5; 125; 250; 500; 1000 µmol.dm-3 of CuCl2 using the Sperm VisionTM CASA (Computer Assisted Semen Analyzer) system. The cell viability was measured by the MTT (metabolic activity) assay. The initial spermatozoa motility showed slightly increased values at doses < 31.20 μmol.dm-3 of CuCl2 compared to the control group. In this time, the lowest spermatozoa motility was recorded significantly (P<0.001) in the group A using the highest dose of CuCl2 (1000 μmol.dm-3). After 1 h of cultivation we proved that the average motility values decreased proportionally to the increasing concentration of CuCl2. The low doses (< 7.80 μmol.dm-3) of CuCl2 increased the spermatozoa motility and concurrently of mitochondrial activity (Time 2 h). The obtained data confirm that Cu (in the form CuCl2) at high doses acts as a toxic element on the spermatozoa motility and it has a destructive effect on the mitochondrial complex, which is necessary for their life processes. The low concentrations (< 7.80 μmol.dm-3) of CuCl2 stimulated the mitochondrial activity of cells and maintained of spermatozoa motility during the short-term of cultivation.