The following abstract presents results of a study conducted by a contract laboratory for the National Toxicology Program. The findings were not evaluated in accordance with the levels of evidence for reproductive or developmental criteria established by NTP in March 2009. The findings and conclusions for this study should not be construed to represent the views of NTP or the U.S. Government.
Diethylene Glycol (DEG), a common chemical and solvent used in industry and in consumer goods, was tested for reproductive toxicity in Swiss CD-1 mice using the RACB protocol. It was part of a large structure-activity series of glycol ethers and congeners evaluated using this design. F0 mice were exposed to drinking water containing 0.0, 0.35%, 1.75%, and 3.5% DEG. Based on water consumption data collected during the study, these concentrations produced calculated DEG consumptions of nearly equal to 612, 3062, and 6125 mg/kg/d.
While F0 body weight was unchanged by DEG consumption during the Task 2 mating period, the number of litters per pair was reduced by 12% at the top dose, and the number of live pups/litter was reduced by 32%. Pup weight adjusted for litter size was reduced by nearly equal to 12% at the top dose level. In a crossover mating to determine the affected sex, number of pups/litter was equivalent across the three groups, but adjusted pup weight was reduced by 10% in the control male x 3.5% DEG female mating. After the F1 mice were weaned, the control and 3.5% DEG F0 mice were killed and necropsied. There were no treatment-related changes in male organ weights or histopathology, while female body weight was reduced by 7% after 3.5% DEG consumption. Adjusted organ weights were unchanged.
For the F1 mating trial, exposed mice from the 1.75% group were used, because insufficient mice were available from the top dose, due to reduced fertility in that group. DEG at 1.75% did not affect pup survival to mating at pnd 74. There were no treatment-related alterations in the number or weight of F2 pups in the Task 4 mating trial. After all the F2 litters were born and the F1 females subjected to estrous cyclicity evaluation, the F1 mice were killed and necropsied. There was an 11% and 7% decrease in the body weights of the treated males and females, respectively. No organ weights were affected, nor were sperm indices changed.
In summary, diethylene glycol at 3.5% was a reproductive toxicant in Swiss mice, based on reductions in litters/pair, and in mean litter size. In F0 mice, this was unaccompanied by body weight loss, while in F1 mice, there was reduced body weight in the absence of a fertility effect.