Multiple Sclerosis Program, Department of Neurology, University of California, Los Angeles, CA 90095-1769, USA.
Brain Pathol. 2013 Jul;23(4):462-75. doi: 10.1111/bpa.12029. Epub 2013 Feb 4.
Sex differences in the structure and organization of the corpus callosum (CC) can be attributed to genetic, hormonal or environmental effects, or a combination of these factors. To address the role of gonadal hormones on axon myelination, functional axon conduction and immunohistochemistry analysis of the CC in intact, gonadectomized and hormone-replaced gonadectomized animals were used. These groups were subjected to cuprizone diet-induced demyelination followed by remyelination. The myelinated component of callosal compound action potential was significantly decreased in ovariectomized and castrated animals under normal myelinating condition. Compared to gonadally intact cohorts, both gonadectomized groups displayed more severe demyelination and inhibited remyelination. Castration in males was more deleterious than ovariectomy in females. Callosal conduction in estradiol-supplemented ovariectomized females was significantly increased during normal myelination, less attenuated during demyelination, and increased beyond placebo-treated ovariectomized or intact female levels during remyelination. In castrated males, the non-aromatizing steroid dihydrotestosterone was less efficient than testosterone and estradiol in restoring normal myelination/axon conduction and remyelination to levels of intact males. Furthermore, in both sexes, estradiol supplementation in gonadectomized groups increased the number of oligodendrocytes. These studies suggest an essential role of estradiol to promote efficient CC myelination and axon conduction in both sexes.
性别差异存在于胼胝体（CC）的结构和组织中，其归因于遗传、激素或环境因素的影响，或者这些因素的组合。为了研究性腺激素对轴突髓鞘形成、功能轴突传导和 CC 免疫组织化学分析的作用，采用了完整、去势和激素替代去势动物的 CC 进行研究。这些组接受了杯状病毒饮食诱导的脱髓鞘，然后进行髓鞘再生。在正常髓鞘形成条件下，去势和去势的动物的 CC 复合动作电位的髓鞘成分显著减少。与性腺完整的队列相比，去势组显示出更严重的脱髓鞘和抑制的髓鞘再生。雄性的去势比雌性的去势更具危害性。在正常髓鞘形成期间，补充雌激素的去势雌性的 CC 传导明显增加，在脱髓鞘期间的衰减较小，并且在髓鞘再生期间超过安慰剂处理的去势或完整雌性水平增加。在去势雄性中，非芳香化类固醇二氢睾酮的效率不如睾酮和雌二醇，无法将正常的髓鞘化/轴突传导和髓鞘再生恢复到完整雄性的水平。此外，在两性中，去势组的雌激素补充增加了少突胶质细胞的数量。这些研究表明，雌激素在促进两性 CC 髓鞘形成和轴突传导方面具有重要作用。
