The decreasing trend in human and domestic animal fertility in recent decades has resulted in the question of whether reduced sperm quality is associated with changes in global climate and the environment. Proposed causes for reduced sperm quality include environmental contaminants, which enter the body of animals through the food chain and are transported to the reproductive tract, where contaminating agents can have effects on fertilization capacities of gametes. Among these, are human-derived contaminants, endocrine-disrupting agents such as pesticides, and naturally occurring toxins such as mycotoxins. Mechanisms by which environmental contaminants reduce male fertility are not clearly defined; however, are apparently multifactorial (i.e., direct and indirect effects) with there being diverse modes of action. Deleterious effects of contaminants on male gametes occur at various stages of spermatogenesis (i.e., in the testis) during passage through the epididymis, and in mature spermatozoa, after ejaculation and during capacitation. The damage includes impairments in acrosome integrity and function, mitochondrial membrane potential and DNA integrity. Here we present new evidence for the long-lasting, multifactorial effects of environmental contaminants on spermatozoa, which carryover to the developing embryos. Exposure of spermatozoa to the contaminants before fertilization altered the transcriptomic profile of the developed embryos. Our findings were directly related to bovine spermatozoa and embryos, but they may also be relevant to humans. Understanding the risk associated with environmental contaminants for animal and human reproduction may lead to new management strategies, thereby improving reproductive processes.
Dr. Alisa Komsky-Elbaz
A Paternal Carry-Over Effect of Environmental Contamination on Preimplantation embryos – A Lesson from Bovines
The Hebrew University of Jerusalem, Israel