Male reproductive organs are at risk from environmental hazards

Abstract

Male reproductive disorders that are of interest from an environmental point of view include sexual dysfunction, infertility, cryptorchidism, hypospadias and testicular cancer. Several reports suggest declining sperm counts and increase of these reproductive disorders in some areas during some time periods past 50 years. Except for testicular cancer this evidence is circumstantial and needs cautious interpretation. However, the male germ line is one of the most sensitive tissues to the damaging effects of ionizing radiation, radiant heat and a number of known toxicants. So far occupational hazards are the best documented risk factors for impaired male reproductive function and include physical exposures (radiant heat, ionizing radiation, high frequency electromagnetic radiation), chemical exposures (some solvents as carbon disulfide and ethylene glycol ethers, some pesticides as dibromochloropropane, ethylendibromide and DDT/DDE, some heavy metals as inorganic lead and mercury) and work processes such as metal welding. Improved working conditions in affluent countries have dramatically decreased known hazardous workplace exposures, but millions of workers in less affluent countries are at risk from reproductive toxicants. New data show that environmental low-level exposure to biopersistent pollutants in the diet may pose a risk to people in all parts of the world. For other toxicants the evidence is only suggestive and further evaluation is needed before conclusions can be drawn. Whether compounds as phthalates, bisphenol A and boron that are present in a large number of industrial and consumer products entails a risk remains to be established. The same applies to psychosocial stressors and use of mobile phones. Finally, there are data indicating a particular vulnerability of the fetal testis to toxicants-for instance maternal tobacco smoking. Time has come where male reproductive toxicity should be addressed form entirely new angles including exposures very early in life.

Sex selection of sperm in farm animals: status report and developmental prospects

“…In addition to mechanical effects , repeated electric charging and electrostatic deflection (3000 V), which are necessary to sort sperm populations, are responsible for the reduced lifespan of sorted spermatozoa observed in most species , 2010, Rath & Johnson 2008. The electrostatic voltage is similar to that used for electroporation, causing a reversible transformation of membrane pores.…”

“…After fusion of the gametes, a series of reprogramming events is activated, which includes DNA methylation, protamine exchange, histone marks, embryonic genome activation and degradation of maternal and paternal transcripts and proteins (Bermejo- Alvarez et al 2008, Kues et al 2008a. A well-orchestrated succession of these events is required to allow normal development, potentially making gametes and early embryos vulnerable to NPs, which may accumulate in the reproductive tract or which are intentionally added to spermatozoa in vitro (Bonde 2010, Ema et al 2010, Schrand et al 2010.…”

Origine développementale et environnementale de l’infertilité masculine

“…Sa perte de fonction entraîne en effet une apoptose massive des cellules germinales lors de la méiose. Ainsi, des souris mâles exposées en période néonatale au diéthylstilbestrol (DES) 6 présentent, à l'âge adulte, une apoptose chronique des cellules germinales qui est associée à une diminution de l'expression de G9a [29]. Le DES exercerait ses effets délétères par l'entremise du récepteur nucléaire NR0B2 (nuclear receptor subfamily 0, group B, member 2).…”

“…Le DES exercerait ses effets délétères par l'entremise du récepteur nucléaire NR0B2 (nuclear receptor subfamily 0, group B, member 2). La conséquence étant que NR0B2 diminue la méthylation des histones 6 Le diéthylstilbestrol (DES) (Distilbène®) est une hormone de synthèse prescrite aux femmes en France entre 1950 et 1977 pendant leur grossesse pour prévenir les fausses couches.…”

“…Le concept de DOHaD s'applique maintenant à d'autres maladies de l'adulte dont l'infertilité masculine. 15 à 20 % des couples présentent des difficultés à concevoir [6] (➜). L'infertilité masculine est impliquée dans plus de la moitié des infertilités du couple.…”