Combined approaches for evaluation of xenoestrogen neural toxicity and thyroid dysfunction: Screening of oxido-nitrosative markers, DNA fragmentation, and biogenic amine degradation.

Anthropogenic chemicals such as parabens and triclosan are used in personal care products. Due to their ability to decrease or prevent bacterial contamination and act as preservatives, these chemicals are used in cosmetic manufacturing processes to increase the shelf life of products. In this study, we assessed the side effects of environmental estrogens (such as the xenoestrogen butylparaben and the antimicrobial agent and preservative triclosan) on thyroid function, brain monoamine levels, and DNA aberration. Forty-two male albino rats were divided into seven groups with six members each: the first group served as control; the second and the third groups were treated with butylparaben 10 and 50 mg/kg body weight, respectively; the fourth and fifth groups were treated with triclosan 10 and 50 mg/kg body weight, respectively; and the sixth and seventh groups were treated with butylparaben plus triclosan 10 and 50 mg/kg body weight, respectively. After 60 days, blood samples were collected and brain specimens were divided into striatum, midbrain, cortex, and thalamus. Thyroid function and levels of monoamines and monoamine metabolites were determined for each brain area. Comet assay was used for brain tissue analysis. The results showed that butylparaben and triclosan and their combinations induced hypothyroidism and disrupted monoamine levels, leading to a decrease in catecholamine and serotonin levels, and accelerated production of 5-hydroxyindoleacetic acid. The obtained data indicate that anthropogenic chemicals such as butylparaben and triclosan have harmful effects on thyroid and brain function and accelerate cell destruction and mutation, as evidenced by single-stranded DNA breaks in the comet assay.