Alterations of Bax/Bcl-2 ratio contribute to NaAsO < sub > 2 < /sub > induced thyrotoxicity in human thyroid follicular epithelial cells and SD rats

Ecotoxicol Environ Saf. 2023 Sep 6;264:115449. doi: 10.1016/j.ecoenv.2023.115449. Online ahead of print.ABSTRACTThe environmental toxicant arsenic causes various human diseases and threatens millions of people worldwide. Recently, a limited number of studies have revealed that exposure to arsenic is associated with thyroid dysfunction, indicating its toxicological impact on the thyroid gland, however, its precise forms of damage and underlying mechanisms remain largely unknown. Here, we sought to observe the thyrotoxicity of sodium arsenite (NaAsO2) on human thyroid follicular epithelial cells (Nthy-ori 3-1) and SD rats, and explore the role of Bax/Bcl-2 ratio in the above process. Our results displayed that NaAsO2 exerted a dose-dependent inhibitory effect on the viability of Nthy-ori 3-1 cells. Alongside the increase doses of NaAsO2 exposure, morphological changes and elevated LDH levels were observed. Furthermore, apoptosis rates increased in a dose- and time-dependent manner, accompanied by a decrease in Bcl-2 and an opposite change in Bax expression. SD rats were treated with 0, 2.5, 5, and 10 mg/kg NaAsO2 for 36 weeks. Our findings revealed that NaAsO2 exposure resulted in arsenic accumulation in thyroid tissue, elevated ratio of Bax/Bcl-2, and histopathological changes of thyroid in rats, which accompanied by the decreased serum T3 and T4 levels and the increased serum TSH level. Furthermore, T3 and T4 levels were negatively correlated with Bax expression, whereas posi...
Source: Ecotoxicology and Environmental Safety - Category: Environmental Health Authors: Source Type: research