A comparative study of the effects of 3 testicular toxicants in cultures of seminiferous tubules of rats or of domestic cats (veterinary waste): An alternative method for reprotoxicology.

In response to the EU cosmetics directive regulation and REACH legislation which encourage cell culture methods in order to reduce or replace the use of animals in toxicology studies, we settled the culture of prepubertal domestic cat seminiferous tubules in our validated BioAlter® model, usually used with prepubertal rat, called here BioAlter®-rat, by opposition to BioAlter®-cat settled here. We carried out a comparative study on the effects of 3 testicular toxicants, 1,3-dinitrobenzene at 60 µM, 2-methoxyacetic acid at 2.5 mM and carbendazim at 50 nM or 500 nM in both BioAlter®-cat and BioAlter®-rat over a 3-week culture period. Sertoli cell or each germ cell populations as well as the levels of Sertoli cell or germ cell specific mRNAs were studied. The harmful effects of the 3 toxicants on pre-meiotic, meiotic and post-meiotic cell numbers and on Sertoli or germ cell specific mRNAs were clearly observed in the two species, even if there might be some small differences in the intensity of the effects on some of the studied parameters. Hence, BioAlter®-cat might be a solution to the requirements of the EU cosmetics directive and REACH legislation for male reproductive toxicology studies.

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.