Distinct Disruptive Effects of Methylparaben and Propylparaben on the Prostate and Gonads of Adult Gerbils

Parabens are chemicals used as preservatives in food, personal care products, and pharmaceuticals. Detectable paraben levels are found in water, air, and soil, making human and animal exposure unavoidable. This study evaluated the effects of methylparaben, propylparaben, and their mixture on the prostate and gonads of male and female gerbils. Gerbils aged 90 days were assigned to the groups: (M) 10 mg/kg/day of methylparaben; (P) 10 mg/kg/day of propylparaben; (M + P) 5 mg/kg/day of methylparaben plus 5 mg/kg/day of propylparaben; (C) control group. The animals were treated orally for 30 consecutive days, and the prostates and gonads were subjected to morphometric-stereological, immunohistochemical, and biochemical analyses. The male ventral prostates in the P and M + P groups showed an increase in relative weight, higher cell proliferation, besides the occurrence of hyperplasia and epithelial desquamation. All treatments reduced malondialdehyde levels in the male prostate. The female prostate exhibited alterations in all treated groups, but with greater severity in the P and M + P groups. These alterations included increased cell proliferation and epithelial hyperplasia, as well as stromal inflammatory foci and increased secretory activity. M, P, and M + P reduced the diameter of the seminiferous tubules, the thickness of the germinal epithelium, and the catalase activity in the testes. In the ovaries, P and M + P reduced the primary follicle number and increased the superoxide dismutase activity. These results indicate that propylparaben is more harmful to the prostate and gonads than methylparaben, and that the acceptable daily intake for these parabens is not safe for reproductive health.