Lead induced alterations in rabbit spermatozoa motility and morphology in vitro

The aim of this in vitro study was to determine the effect of lead chloride (PbCl2) on rabbit spermatozoa motility and morphology. Lead concentrations in the medium ranged between 0.45 and 11.17 μg/ml; incubation time was 240 min (analyzed immediately after Pb addition followed by 30, 60, 120, 180, and 240 min), and temperatures of the culture environment were 22°C (laboratory), 4°C (refrigerator), and 37°C (incubator). Results were compared with a control group without Pb addition. After 30 min of culture at 22°C, a negative effect of Pb was noted as spermatozoa motility significantly decreased in groups with higher concentrations. After 120 and 240 min, a dose-dependent effect on spermatozoa motility was noted. At 4°C, spermatozoa motility analysis detected no significant differences between any of the experimental groups and control. At 37°C, a negative effect of Pb incubation on motility was detected at Times 30, 60, 120, 180, and 240 in groups with high concentrations. At Times 120, 180, and 240 a significant decrease in spermatozoa motility was also noted in all experimental groups in comparison to control. The analysis of pathological spermatozoa at Time 240 revealed an increasing trend of morphological abnormalities after incubation with Pb. Across three temperature regimes an increase of morphological changes was noted, particularly in the group with the highest Pb concentration. The predominant morphological abnormalities were knob twisted flagellum, flagellum ball, separated flagellum, and broken flagellum. Knob twisted flagella represented the most frequent pathological changes in the experimental group with the highest Pb concentration. Results suggest that the inhibitory effect of Pb on spermatozoa motility parameters depends on the concentration, incubation time, as well as environmental temperature during incubation. Furthermore, a negative effect of Pb in vitro on spermatozoa morphology indicates possible reproductive problems under in vivo conditions, too.