Effects of an Environmentally Relevant Organochlorine Mixture and a Metabolized Extract of This Mixture on Porcine Sperm Parameters In Vitro

Abstract

Organochlorine chemicals are present in the environment worldwide; however, populations living in the Far North are particularly at risk because their traditional diets are mainly composed of contaminated animals (fish, seals, whales, and polar bears). It has been suggested that male fertility is globally declining, possibly because of chronic, low-level exposure to environmental contaminants. This study was designed to assess the effects on fresh sperm fertility parameters using the porcine model of 1) an environmentally relevant mixture of 15 organochlorines and 2) the metabolized extract of this mixture. In the first experiment, the organochlorine mixture (at relative concentrations of 10.5, 14.7, and 21 mg/mL polychlorinated biphenyls [PCBs]) reduced sperm total motility, progressive motility, and viability, and increased capacitation, spontaneous acrosome reaction rates, and cytosolic calcium levels, suggesting that the mixture alters the sperm membrane and is detrimental to sperm function. In the second experiment, the metabolized extract of this organochlorine mixture (at relative concentrations of 0.9, 1.8, 2.7, 3.6, and 4.5 mg/L OH-PCBs) tended to decrease only sperm total motility. In an in vitro porcine model, the mixture of organochlorines, as found in the Arctic food chain, was rapidly detrimental to sperm function at concentrations above environmental levels. In contrast, short and physiologically relevant exposure to the metabolized extract of this mixture induced only limited adverse effects on sperm motility.

Di-n-Butyl Phthalate (DBP) Exposure Induces Oxidative Damage in Testes of Adult Rats

“…Recently, there has been increased awareness of the possible effects of environmental contaminants on male reproduction [Martino-Andrade et al 2010;Campagna et al 2009]. …”

17β-estradiol and xenoestrogens reveal synergistic effect on mitochondria of human sperm

“…Incubation of sperm cells with E2, genistein, and BPA at a final concentration of 10 -10 mol/L resulted in a greater decrease in ΔΨm than stimulation with the use of only one factor, E2 or BPA, at a concentration of 10 -6 mol/L. E2 and xenoestrogens have been suggested to stimulate the increase in intracellular Ca 2+ level [33][34][35]. It is proposed that the increase in calcium ion concentration stimulated by estrogens may activate mitochondrial protein phosphatase, which in turn dephosphorylates cytochrome c oxidase.…”

Endocrine distrupting chemicals and human health: The plausibility of research results on DDT and reproductive health

“…A number of studies have come up with the ever-disturbing results of EDCs as culprits in the decline in reproductive potential of men and women in the general population. 26 Unfortunately, in most studies, toxicological information is incomplete, endocrine disruptors are almost exclusively tested alone 24 or as dimeric mixtures (combinations), 27 yet the human population is exposed to multiple disruptors throughout the day. In most animal testing experiments only one chemical is looked at in evaluating health effects at a time a strategy that fails to provide information about interactive effects, which may occur with exposure to more than one chemical.…”

“…Some studies have further gone to demonstrate the effects of organochlorines in mixtures, DDT included, on sperm parameters and function in vitro. The physiologicallyrelevant metabolized extracts used by Campagna et al in 2009 27 contained organochlorines concentrations 5,000 to 10,000-fold lower than the environmentally relevant mixture that induced marked effects on male reproductive function in vivo in studies published by Bailey in 2002 28 and Anas et al in 2005. 29 However though the study concluded that exposure to the environmentally-relevant organochlorine mixture altered normal sperm fertility parameters in vitro the concentrations used were far higher than those found in human body fluids.…”

“…In view of this studies looking at environmental and other effects on sperm count in men have to take account of season, in addition to the other factors that have been discussed. Most of the studies on male sub fecundity concentrate on effects of the endocrine disruptors on sperm parameters such as volume, concentration and motility 27 without giving a clear view of the fertilizing potential of the sperm with deranged parameters. 39,40 The significance of these conflicting reports is unclear, largely because the data are often derived from ecological sources.…”