成年大鼠基底前脑nestin阳性神经元的性别差异

为了探讨成年雌雄大鼠基底前脑nestin阳性神经元的性别差异及其意义,本实验应用免疫组织化学方法对正常成年雌雄SD大鼠及去势2周和4周的雌雄SD大鼠基底前脑的内侧隔核(MS)、斜角带垂直支(vDB)及斜角带水平支(hDB)的nestin阳性神经元的变化进行了比较研究。结果显示正常雌雄大鼠MS、vDB及hDB的nestin阳性神经元数十分接近(P>0.05);而去睾丸2周大鼠组MS、vDB、hDB的nestin阳性神经元数则明显高于去卵巢2周大鼠组(P<0.05,P<0.01);去睾丸4周大鼠组vDB、hDB的nestin阳性神经元数依然明显高于去卵巢4周大鼠组(P<0.05),但两组MS间的nestin阳性神经元数差别不大(P>0.05);各组大鼠的nestin阳性神经元的胞体和树突均相似。以上结果表明,正常成年雌雄大鼠基底前脑的nestin阳性神经元数不存在性别差异,无论去势与否,nestin阳性神经元的形态始终不存在性别差异;而去势后nestin阳性神经元数却存在着明显的性别差异。提示基底前脑nestin阳性神经元的性别差异不仅与雌激素和雄激素在雌雄个体中所发挥的不同作用密切相关,而且还可能是促使学习记忆出现性别差异的形态学基础。

SEX DIFFERENCES OF NESTIN IMMUNOREACTIVE NEURONS IN ADULT RAT BASAL FOREBRAIN

To explore the sex differences of nestin immunoreactive (nestin-IR) neurons in the adult rat basal forebrain, the changes of nestin-IR neurons in the medial septum (MS), vertical (vDB) and horizontal (hDB) limbs of the diagonal band of Broca in the basal forebrain were compared between adult intact female and male SD rats, and between ovariectomized female SD rats and castrated SD male rats by means of immunohistochemical technique. It was found that no significant differences in the number of nestin-IR neurons in MS, vDB and hDB existed between intact female and male rats. However, the number of nestin-IR neurons in the above three subregions of castrated male rats for 2 or 4 weeks was significantly greater than that of ovariectomized female rats with the exception of the number in MS between castrated male rats and ovariectomized female rats for 2 weeks. No obvious alteration for the somas or dendrites of nestin-IR neurons existed in the above three subregions among intact or gonadectomized female and male rats. The above results show that sex differences of the number of nestin-IR in adult basal forebrain only exist between ovariectomized female rats and castrated male rats, while no sex differences of the number of nestin-IR neurons exist between intact female and male rats. No sex difference was observed in the shape of nestin-IR neurons among intact or gonadectomized female and male rats. The present results suggest that sex differences of the number in nestin-IR neurons not only are closely related to the different roles of estrogen and androgen in female and male individuals, but also can be morphological foundations for sex differences in learning and memory.