Lovekamp-Swan Tara, Glendenning Michele L, Schreihofer Derek A
Department of Physiology, CA3145, Medical College of Georgia, 1120 15th Street, Augusta, GA 30912-3000, USA.
Brain Res. 2007 Jul 23;1159:54-66. doi: 10.1016/j.brainres.2007.05.026. Epub 2007 May 26.
Estrogen is a powerful neuroprotective agent with the ability to induce trophic and antiapoptotic genes. However, concerns about negative overall health consequences of estrogen replacement after menopause have led to the adoption of other strategies to obtain estrogen's benefits in the brain, including the use of selective estrogen receptor modulators, high soy diets, or isoflavone supplements. This study sought to determine the ability of a high soy diet to induce neuroprotective gene expression in the female rat brain and compare the actions of soy with estrogen. Adult ovariectomized female rats were treated with 3 days of high dose estrogen or 2 weeks of a soy-free diet, a high soy diet, or chronic low dose estrogen. Different brain regions were microdissected and subjected to real time RT-PCR for neuroprotective genes previously shown to be estrogen-regulated. The principle findings are that a high soy diet led to the widespread increase in the mRNA for neurotropin receptors TrkA and p75-NTR, and the antiapoptotic Bcl-2 family member Bcl-X(L). Immunohistochemistry confirmed increases in both TrkA and Bcl-X(L). Chronic low dose estrogen mimicked some of these effects, but acute high dose estrogen did not. The effects of a high soy diet were particularly evident in the parietal cortex and hippocampus, two regions protected by estrogen in animal models of neurological disease and injury. These results suggest that a high soy diet may provide beneficial effects to the brain similar to low dose chronic estrogen treatment such as that used for postmenopausal hormone replacement.
雌激素是一种强大的神经保护剂，具有诱导营养和抗凋亡基因的能力。然而，对绝经后雌激素替代疗法对整体健康产生负面影响的担忧，促使人们采取其他策略来获取雌激素对大脑的益处，包括使用选择性雌激素受体调节剂、高大豆饮食或异黄酮补充剂。本研究旨在确定高大豆饮食诱导雌性大鼠大脑中神经保护基因表达的能力，并比较大豆与雌激素的作用。成年去卵巢雌性大鼠分别接受3天高剂量雌激素治疗、2周无大豆饮食、高大豆饮食或慢性低剂量雌激素治疗。对不同脑区进行显微切割，并对先前已证明受雌激素调节的神经保护基因进行实时逆转录聚合酶链反应（RT-PCR）。主要研究结果是，高大豆饮食导致神经营养因子受体TrkA和p75-NTR以及抗凋亡Bcl-2家族成员Bcl-X(L)的mRNA广泛增加。免疫组织化学证实TrkA和Bcl-X(L)均增加。慢性低剂量雌激素模拟了其中一些作用，但急性高剂量雌激素则没有。高大豆饮食的作用在顶叶皮质和海马体中尤为明显，在神经疾病和损伤的动物模型中，这两个区域受到雌激素的保护。这些结果表明，高大豆饮食可能为大脑提供类似于低剂量慢性雌激素治疗（如用于绝经后激素替代疗法）的有益作用。
