Direct and In-Utero Exposure to Quaternary Ammonium Disinfectants Alters Sperm Parameters and mRNA Expression of Epigenetic Enzymes in the Testes of Male CD-1 Mice

Quaternary ammonium compounds (QACs) are a class of chemicals used for their antimicrobial, surfactant, and antistatic properties. QACs are present in many consumer products, and people are regularly exposed to them. We have previously shown reproductive toxicity in mice exposed to the disinfectants alkyl dimethyl benzyl ammonium chloride (ADBAC) and dodecyl dimethyl ammonium chloride (DDAC). To assess the long-term reproductive impacts, a generational reproductive study was conducted. Sperm parameters were determined by CASA and epigenetic enzyme mRNA expression was determined by pathway-focused RT-PCR. Mice ambiently exposed to ADBAC+DDAC exhibited decreases in reproductive indices that persisted through the F1 generation. Male mice (F0) dosed with 120 mg/kg/day of ADBAC+DDAC exhibited decreased sperm concentration and motility that persisted through the F1 generation. Changes in the mRNA expression of chromatin-modifying enzymes in the testes were seen. Two histone acetyltransferases (Hat1 and Kat2b) were upregulated, and one lysine-specific demethylase (Kdm6b) was downregulated in the F0 generation. The DNA methyltransferase Dnmt1 was downregulated in F1 males. These changes in chromatin-modifying enzymes are known to decrease fertility and could be a mechanism for ADBAC+DDAC reproductive toxicity. In all experiments, the F2 generation was similar to the controls, showing multi-generational but not trans-generational epigenetic inheritance.