Impact of subchronic exposure to triclosan and/or fluoride on estrogenic activity in immature female rats: The expression pattern of calbindin‐D9k and estrogen receptor α genes

Abstract

This study explored the influence of triclosan (TCS) in the absence and presence of sodium fluoride (NaF) on estrogenic activity and thyroid function of adolescent female rats. The results indicated that the individual exposure to TCS evoked a significant decline in T and T but the levels of estradiol, FSH, and LH were significantly elevated beside marked up regulation of calbindin-D9k and estrogen α mRNA expression. On the other hand, the single exposure to NaF causes insignificant changes in thyroid hormones, but evoked a trend toward an increase in both estradiol and LH levels. No significant differences in the TSH level were recorded among the experimental groups. The joint exposure to TCS and NaF induced a significant improvement in thyroid and reproductive hormone levels. Overall, these findings revealed that exposure to TCS resulted in significant endocrine and reproductive alterations in immature female rats, while TCS + NaF coexposure resulted in lessening most effects.

Comprehensive insight into triclosan—from widespread occurrence to health outcomes

“…Endocrine disrupting properties of TCS were also examined in various animal models within a wide range of doses and dosing regimens, which makes the obtained results difficult to compare. For instance, administration of TCS in concentration up to 0.345 mmol/kg/day resulted in a decrease of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in female mice (Cao et al 2018), while at the higher oral dose (0.639 mmol/ kg/day), increased both FSH and LH were measured in Sprague Dawley rats (Abd-Elhakim et al 2018). However, a comparable reduction in thyroid hormones, T3 and T4, was observed in male Wistar albino rats (Taha et al 2020), female Sprague Dawley rats (Abd-Elhakim et al 2018) and female mice (Cao et al 2018).…”

“…For instance, administration of TCS in concentration up to 0.345 mmol/kg/day resulted in a decrease of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in female mice (Cao et al 2018), while at the higher oral dose (0.639 mmol/ kg/day), increased both FSH and LH were measured in Sprague Dawley rats (Abd-Elhakim et al 2018). However, a comparable reduction in thyroid hormones, T3 and T4, was observed in male Wistar albino rats (Taha et al 2020), female Sprague Dawley rats (Abd-Elhakim et al 2018) and female mice (Cao et al 2018). The findings are in agreement with the in vitro data suggesting TCS hypothyroidism-inducing effects (Butt et al 2011).…”

The Influence of Triclosan on the Thyroid Hormone System in Humans - A Systematic Review

“…Structurally, triclosan resembles thyroxine (T4), ( Figure 2 ) and it can disrupt the thyroid hormone system ( 9 – 12 ). Thus, in rodents, triclosan consistently reduces serum T4 concentrations, probably by increasing hepatic catabolism of thyroid hormones ( 9 , 13 , 14 ).…”

Deodorants and antiperspirants: identification of new strategies and perspectives to prevent and control malodor and sweat of the body

“…It is incorporated into fabrics and polymers for the production of clothing and packaging that provides protection against microorganisms in sporting goods and food. In the personal care business, triclosan is the main antimicrobial used in soaps, shampoos, creams, lotions, toothpastes, and also in deodorants 1,20 …”

“…The current concern is the increase in reports of detection of triclosan and its metabolites in environmental matrices and their ecotoxicological damage. Although the concentrations found are in the nano‐ and picograms/L range, it is already known that such quantities can have harmful effects on aquatic organisms and that their presence in the water used for irrigation causes bioaccumulation in the food consumed by humans 22,20,2 …”