2012年9月8日 讯 /生物谷BIOON/ --近日，来自北卡罗来纳州立大学的研究者表示，年轻时暴露于化学双酚A（BPA），可以促使大脑杏仁核特定区域的基因表达发生改变，进而引发机体高度焦虑症。研究者同时发现富含大豆的饮食可以缓解高焦虑的表现。相关研究成果刊登在了9月5日的国际杂志PLoS One上。
我们都知道BPA可以引发焦虑。BPA常用于聚碳酸盐塑料和环氧树脂中，而且其在消费品如食物容器中也常常使用。在文章中，研究者使鼠类分别在怀孕期间、哺乳期间以及整个青春期期间暴露于低剂量的BPA中，其中一组仅仅以大豆喂食；一组以无大豆食品喂食；另外一组暴露于BPA中，且同时以大豆喂食，最后一组仅仅暴露于BPA中，不以大豆进行喂食。通过实验发现，暴露于BPA中的动物，其血液中的BPA水平和人类一样维持在一定水平。类似地，研究者也检测了喂食大豆的动物血液中染料木黄酮的水平，发现其水平也和人类一样维持在一定范围之内。
在无大豆喂食的青春期鼠中，暴露于BPA的鼠表现出了明显的高焦虑症，研究者同时发现，其大脑中基因的改变和焦虑的提高明显相关。研究揭示了大脑杏仁核区域的基因表达改变和机体行为改变明显相关。其中两个受影响的基因是雌激素受体β和黑皮质素受体4，两个都是催产素释放所必须的，然而催产素信号路径的改变或许会促使这种行为的改变。催产素是一种激素，其也是一种和社会行为相关的神经递质。
研究者发现，给予大豆喂食的青春期鼠类并不会产生焦虑情绪，这也就表明，富含大豆的饮食或许会减缓BPA所带来的效应，但是其具体的分子机理尚不清楚。研究者Patisaul表示，大豆中包含有植物雌激素，其可以影响内分泌系统，而内分泌系统可以调节激素的分泌。目前是否植物雌激素可以缓解BPA所带来的效应，我们并不清楚，后期研究我们将重点进行此项机理研究。（生物谷Bioon.com）
编译自：Study finds how BPA affects gene expression, anxiety; Soy mitigates effects
doi:10.1371/journal.pone.0043890
PMC:
PMID:
Anxiogenic Effects of Developmental Bisphenol A Exposure Are Associated with Gene Expression Changes in the Juvenile Rat Amygdala and Mitigated by Soy
Heather B. Patisaul1,2*, Alana W. Sullivan1,2, Meghan E. Radford1,2, Deena M. Walker3, Heather B. Adewale1,2, Bozena Winnik4, Janis L. Coughlin4, Brian Buckley5, Andrea C. Gore3
Early life exposure to Bisphenol A (BPA), a component of polycarbonate plastics and epoxy resins, alters sociosexual behavior in numerous species including humans. The present study focused on the ontogeny of these behavioral effects beginning in adolescence and assessed the underlying molecular changes in the amygdala. We also explored the mitigating potential of a soy-rich diet on these endpoints. Wistar rats were exposed to BPA via drinking water (1 mg/L) from gestation through puberty, and reared on a soy-based or soy-free diet. A group exposed to ethinyl estradiol (50 µg/L) and a soy-free diet was used as a positive estrogenic control. Animals were tested as juveniles or adults for anxiety-like and exploratory behavior. Assessment of serum BPA and genistein (GEN), a soy phytoestrogen, confirmed that internal dose was within a human-relevant range. BPA induced anxiogenic behavior in juveniles and loss of sexual dimorphisms in adult exploratory behavior, but only in the animals reared on the soy-free diet. Expression analysis revealed a suite of genes, including a subset known to mediate sociosexual behavior, associated with BPA-induced juvenile anxiety. Notably, expression of estrogen receptor beta (Esr2) and two melanocortin receptors (Mc3r, Mc4r) were downregulated. Collectively, these results show that behavioral impacts of BPA can manifest during adolescence, but wane in adulthood, and may be mitigated by diet. These data also reveal that, because ERβ and melanocortin receptors are crucial to their function, oxytocin/vasopressin signaling pathways, which have previously been linked to human affective disorders, may underlie these behavioral outcomes.
