Low concentrations of glyphosate alone affect the pubertal male rat meiotic step: An in vitro study

Glyphosate is the most used herbicide in the world. Controversial studies exist on its effect on the male reproductive system. We used the validated BioAlter® model to test the effects of low concentrations of Glyphosate. Pubertal rat seminiferous tubules were treated with Glyphosate 50 nM, 500 nM, 5 μM or 50 μM over a 3-week culture period. The Trans-Epithelial Electrical Resistance was not modified by any of the concentrations. The decrease of Clusterin mRNAs suggested that glyphosate would target the integrity of Sertoli cells. The decrease of the numbers of germ cells from day 14 onward highlighted the chronic effect of glyphosate at 50 nM, 500 nM or 5 μM. No consistent effect of glyphosate was observed on the numbers of spermatogonia or on their specific mRNA levels. However, those low concentrations of glyphosate targeted young spermatocytes and middle to late pachytene spermatocytes resulting in a decrease of the numbers of round spermatids, the direct precursors of spermatozoa. This study underlines that the effect of a toxicant should be also studied at low doses and during the establishment of the blood-testis barrier.