Testicular toxicity of 2-methoxyacetaldehyde, a possible metabolite of ethylene glycol monomethyl ether, in the rat

2-Methoxyacetaldehyde (MALD) was shown to produce specific cellular toxicity to pachytene spermatocytes in mixed testicular cell cultures as evidenced by morphological changes to these cells, an increase in germ-cell detachment and leakage of the pachytene spermatocyte marker enzyme lactate dehydrogenase-X. These effects occurred at concentrations where the known testicular toxicant, 2-methoxyacetic acid (MAA) was without effect (0.2 and 0.5 mM). In vivo, MALD also produced the characteristic testicular lesion reported previously for MAA and its parent compound ethylene glycol monomethyl ether (EGME). It is likely that MALD plays an important role in EGME-induced testicular toxicity.