Evaluation of Low-Dose Effects and Non-Monotonous Dose Response of Butyl p-hydroxybenzoate, or Butylparaben on Female Wistar Rats

Butylparaben (BP) is an extensively used synthetic preservative that has been testified as an endocrine disruptor and speculated to be toxic for the body all together. The present study evaluated the possible noxious impact of BP at minimum doses, i.e., 1, 5, and 10 mg/kg BW/day, on female Wistar rats following consecutive subcutaneous exposure for 7 and 21 days. The results of the genotoxic study exhibited that BP at a dose of 10 mg/kg BW/day significantly (p ˂ 0.05) induced micronucleated polychromatic erythrocytes (MNPCEs) formation in bone marrow of rats, both in short (7.3 ± 0.87 MNPCEs/1000 PCEs) and long-term exposures (6.6 ± 0.33 MNPCEs/1000 PCEs), which was in line with the results obtained for 17β-estradiol (E2)-treated reference control rats. Levels of hepatic toxicity marker enzymes, i.e., aspartate transaminase (AST) and alanine transaminase (ALT), were not altered substantially in any of the study durations, but the alkaline phosphatase (ALP) level increased significantly (p ˂ 0.05) at all BP doses, including E2. Variations in the serum HDL as well as cholesterol levels were found to be non-monotonous with respect to the applied BP doses. However, contrasting specifics were observed for triglycerides in terms of the study durations. Conclusively, the current study established that BP, even at low doses, could evidently disturb the circulating lipid content, hepatic enzyme levels, and even cause genotoxicity, and also pointed toward its non-monotonous dose response.