Zhang Yuhui, Li Xinyi, Gao Jinshu, Wang Hongyuan
College of Life Science, Shaanxi Normal University, Xi'an, 710119, China.
Environ Toxicol. 2018 Jan;33(1):112-121. doi: 10.1002/tox.22504. Epub 2017 Nov 3.
In the present study, responses of the Chinese brown frog (Rana chensinensis) to exposure to di-2-ethylhexyl phthalate (DEHP), a common plasticizer, during the larval period were characterized. The effects of DEHP on metamorphosis rate, thyroid hormone, thyroid histology and the expression of genes involved in the steroid hormone synthesis in gonad were investigated. Metamorphosis rate and 50 percent of the tadpoles to reach Gosner stage 42 (T ) were significantly slower in all DEHP groups. The thyroid glands of the tadpoles exposed to DEHP clearly exhibited colloid depletion. In addition, decreased concentrations of T4 and T3 were observed in the tadpoles exposed to DEHP. Moreover, the highest DEHP exposure (10 µmol/L DEHP) showed increased ratio of females significantly. Also, up-regulation significantly of transcripts of cytochrome P450 aromatase (CYP19) gene was detected in male tadpoles exposed to DEHP. The present results indicate that this increase in estrogens could lead to female-biased sex ratio in DEHP exposure group. Taken together, the present study indicates that DEHP disrupt thyroid hormone and sex steroid signaling in R. chensinensis tadpoles. Our present observations support evidence of a crosstalk between TH and sex steroids in gonad differentiation.
在本研究中，对中国林蛙（Rana chensinensis）幼体期暴露于常见增塑剂邻苯二甲酸二（2-乙基己基）酯（DEHP）后的反应进行了表征。研究了DEHP对变态率、甲状腺激素、甲状腺组织学以及性腺中参与类固醇激素合成的基因表达的影响。所有DEHP组的变态率以及50%的蝌蚪达到戈斯纳42期（T）的时间均显著延长。暴露于DEHP的蝌蚪甲状腺明显出现胶体减少。此外，在暴露于DEHP的蝌蚪中观察到T4和T3浓度降低。而且，最高剂量的DEHP暴露（10 µmol/L DEHP）使雌性比例显著增加。同时，在暴露于DEHP的雄性蝌蚪中检测到细胞色素P450芳香化酶（CYP19）基因转录本显著上调。目前的结果表明，雌激素的这种增加可能导致DEHP暴露组出现雌性偏多的性别比例。综上所述，本研究表明DEHP扰乱了中国林蛙蝌蚪的甲状腺激素和性类固醇信号。我们目前的观察结果支持了甲状腺激素和性类固醇在性腺分化中存在相互作用的证据。
