Tianjin Institute of Environmental and Operational Medicine, Tianjin 300050, China.
Biomed Res Int. 2020 Jun 17;2020:4701563. doi: 10.1155/2020/4701563. eCollection 2020.
High-temperature exposure is detrimental to women's reproductive health; however, the impact caused by long-term high temperature is not comprehensive, and a stable model of estrous cycle disorder induced by a high temperature is yet lacking. Herein, we aimed to establish a stable and effective model of estrous cycle disorder in female rats induced by long-term heat stress to study its physiological and pathological characteristics and explore the underlying mechanism. In the present study, female Sprague-Dawley rats with normal estrous cycles were exposed to the temperature of 38 ± 0.5°C, relative humidity (RH) of 55 ± 5% (2 h/d, 1 time/d) hot cabin at more than 90 days. Consequently, after long-term heat stress, no difference was detected in body weight and rectal temperature, but the estrus cycle was prolonged, the uterine organ index was increased, pathological changes occurred, the increase latitude of stress hormones heat shock protein 70 (Hsp70) and corticosterone (CORT) decreased, estradiol (E) and luteinizing hormone (LH) levels decreased, follicle stimulating hormone (FSH) and prolactin (Prl) levels increased, gonadotropin-releasing hormone (GnRH) and thyroid hormone (T) showed no difference, and insulin (INS) decreased significantly. Moreover, the mRNA expression of the sex hormone receptor in the uterus and ovary was altered. Therefore, the estrous cycle disorder in female rats can be induced by regular heat stress for 90 days, which can be considered the pioneer method. Subsequently, prominent physiological and pathological characteristics and disruption in the hypothalamic-pituitary-gonadal (HPG) axis were noted.
高温暴露对女性生殖健康有害；然而，长期高温造成的影响并不全面，也缺乏稳定的发情周期紊乱模型。在此，我们旨在建立一种稳定而有效的长期热应激诱导雌性大鼠发情周期紊乱模型，以研究其生理和病理特征，并探讨其潜在机制。在本研究中，正常发情周期的雌性 Sprague-Dawley 大鼠在 38±0.5°C 的温度、55±5%（2 小时/天，1 次/天）的相对湿度（RH）下进行热舱暴露 90 天以上。结果显示，经过长期热应激后，大鼠体重和直肠温度没有差异，但发情周期延长，子宫器官指数增加，发生了病理变化，应激激素热休克蛋白 70（Hsp70）和皮质酮（CORT）的增加幅度减小，雌二醇（E）和促黄体生成素（LH）水平降低，促卵泡生成素（FSH）和催乳素（Prl）水平升高，促性腺激素释放激素（GnRH）和甲状腺激素（T）没有差异，胰岛素（INS）显著降低。此外，子宫和卵巢中性激素受体的 mRNA 表达发生改变。因此，通过 90 天的定期热应激可以诱导雌性大鼠发情周期紊乱，这可以被认为是一种开创性的方法。随后，观察到明显的生理和病理特征以及下丘脑-垂体-性腺（HPG）轴的破坏。
