Department of Comparative Biosciences, University of Illinois at Urbana-Champaign, Urbana, IL 61802, United States.
Neurotoxicol Teratol. 2013 Jan-Feb;35:46-53. doi: 10.1016/j.ntt.2013.01.002. Epub 2013 Jan 20.
Over 90% of the U.S. population has detectable bisphenol-A (BPA) in their urine according to recent biomonitoring data. BPA is best known for its estrogenic properties, and most rodent research on the nervous system effects of BPA has focused on determining if chronic exposures during pre- and perinatal development have organizational effects on brain development and behavior. Estrogens also have important impacts on brain and behavior during adulthood, particularly in females during aging, but the impact of BPA on the adult brain is less studied. We have published a series of studies documenting that chronic exposure to various estrogens including 17β-estradiol, ERβ selective SERMs and soy phytoestrogens impairs performance of middle-aged female rats on an operant working memory task. The purpose of this study was to determine if chronic oral exposure to BPA would alter working memory on this same task. Ovariectomized (OVX) middle-aged Long Evans rats were tested on an operant delayed spatial alternation (DSA) task. Rats were treated for 8-10 weeks with either a 0 (vehicle control), 5 or 50 μg/kg bw/day oral bolus of BPA. A subset of the vehicle control rats was implanted with a Silastic implant containing 17β-estradiol (low physiological range) to serve as a positive control. All rats were tested for 25 sessions on the DSA task. BPA treatment did not influence performance accuracy on the DSA task, whereas 17β-estradiol significantly impaired performance, as previously reported. The results of this study suggest that chronic oral exposure to BPA does not alter working memory processes of middle-aged OVX rats assessed by this operant DSA task.
根据最近的生物监测数据，超过 90%的美国人口尿液中可检测到双酚 A（BPA）。BPA 以其雌激素特性而闻名，大多数关于 BPA 对神经系统影响的啮齿动物研究都集中在确定在产前和围产期的慢性暴露是否对大脑发育和行为具有组织效应。雌激素在成年期对大脑和行为也有重要影响，特别是在女性衰老过程中，但 BPA 对成年大脑的影响研究较少。我们已经发表了一系列研究，记录了慢性暴露于各种雌激素，包括 17β-雌二醇、ERβ 选择性 SERM 和大豆植物雌激素，会损害中年雌性大鼠在操作性工作记忆任务上的表现。本研究的目的是确定慢性口服暴露于 BPA 是否会改变大鼠在相同任务上的工作记忆。进行了去卵巢（OVX）中年长爪沙鼠的操作性延迟空间交替（DSA）任务测试。大鼠用 0（载体对照）、5 或 50μg/kg bw/天的口服 BPA 进行 8-10 周的治疗。载体对照组大鼠的一部分被植入含有 17β-雌二醇（低生理范围）的 Silastic 植入物，作为阳性对照。所有大鼠都在 DSA 任务上进行了 25 次测试。BPA 处理并未影响 DSA 任务的表现准确性，而 17β-雌二醇则如先前报道的那样显著损害了表现。这项研究的结果表明，慢性口服暴露于 BPA 不会改变通过该操作性 DSA 任务评估的中年 OVX 大鼠的工作记忆过程。
