ASSESSMENT OF THE DEVELOPMENTAL TOXICITY OF ETHYLENE-GLYCOL APPLIED CUTANEOUSLY TO CD-1 MICE

Ethylene glycol (EG; CAS No. 107-21-1) is teratogenic to mice by whole-body exposure to an aerosol at high concentrations, but results were confounded by possible exposure from ingestion after grooming and/or from percutaneous absorption. Therefore, CD-1 mice were exposed to EG on Gestational Days (GD) 6 through 15, 6 hr/day by occluded cutaneous application at 0, 12.5, 50, or 100% (undiluted) EG (0.1 ml/animal, equivalent to similar to 0, 404, 1677, or 3549 mg/kg/day, respectively) or by gavage on GD 6 through 15 at 3000 mg/kg/day [10 ml/kg, positive control gavage group (PCGG)], 30 females/group. Dams were weighed and evaluated daily (including application site) for clinical signs and water consumption throughout gestation. On GD 18, maternal uterus, liver, and paired kidneys were weighed; kidneys of 0 and 100% and the PCGG were examined microscopically. Corpora lutea and implantation sites were recorded. Live fetuses were weighed, sexed, and examined for structural alterations. For cutaneously exposed dams, there was no treatment-related maternal toxicity, no differences in pre- or postimplantation loss or in fetal body weights/ litter, and no increased incidences of any fetal malformations. Two skeletal variations, increased at 100%, may represent effects of restraint stress and/or findings due to chance. In the PCGG, 8 females (26.7%) died, water consumption was increased, fetal body weights/litter were reduced, and fetal malformations and variations were increased. PCGG kidneys exhibited tubular nephrosis and tubular cell degeneration, with no oxalate crystals, documenting renal toxicity at this oral dose in mice. Minimal-grade renal tubular lesions observed in 3 mice (of 30) at 100% EG may represent treatment-related or incidental findings. Therefore, exposure of pregnant CD-1 mice to 0, 12.5, 50, or 100% EG during organogenesis by occluded cutaneous application resulted in minimal or no observable maternal or developmental toxicity at 100% (similar to 3549 mg/kg/day), the NOEL. (C) 1995 Society of Toxicology