Effect of chemical pollution on the fertility of male rodents from natural populations: сomparing the response of sperm morphology, motility, and concentration

Abstract

The results of studies of epididymal spermatozoa of three species of rodents (bank vole Clethrionomys glareolus, northern red-backed vole Cl. rutilus, and herb field mouse Sylvaemus uralensis) living under long-term exposure to atmospheric emissions from two large copper smelters in the Middle Urals are summarized (Middle Ural and Kirovgrad copper smelters). The impact of pollution (including at the individual level on the accumulation of Cu, Zn, Pb, and Cd in the liver) was assessed for indicators characterizing the quality of sperm from different aspects: morphology (proportion of cells with head and tail defects), motility (proportion of motile cells, velocity, and straightness of movement) and concentration. Sperm motility responds to pollution: in impact zones, the proportion of motile cells and their velocity were lower than in background zones. The occurrence of abnormal cells and sperm concentration were not statistically significantly different between impact and background zones. The reaction of sperm to chemical pollution is species-specific: voles react more strongly than the herb field mouse. The consistency of changes in sperm parameters (in the direction of their deterioration) in response to increased pollution was found only in the bank vole. Effect sizes for sperm parameters are much smaller compared to those for liver Cd accumulation and animal abundance. In general, the reaction of sperm to pollution turned out to be weak, none of the studied indicators can be a reliable marker of industrial pollution.