Pei Minjuan, Matsuda Ken-Ichi, Sakamoto Hirotaka, Kawata Mitsuhiro
Department of Anatomy and Neurobiology, Kyoto Prefectural University of Medicine, Kawaramachi Hirokoji, Kamigyo-ku, Kyoto, Japan.
Eur J Neurosci. 2006 Mar;23(5):1234-40. doi: 10.1111/j.1460-9568.2006.04661.x.
Previous studies on polytocous rodents have revealed that the fetal intrauterine position influences its later anatomy, physiology, reproductive performance and behavior. To investigate whether the position of a fetus in the uterus modifies the development of the brain, we examined whether the structure of the sexually dimorphic nucleus of the preoptic area (SDN-POA) of rat brains accorded to their intrauterine positions. Brain sections of adult rats gestated between two male fetuses (2M) and between two female fetuses (2F) in the uterus were analysed for their immunoreactivity to calbindin-D28k, which is a marker of the SDN-POA. The SDN-POA volume of the 2M adult males was greater than that of the 2F adult males, whereas the SDN-POA volume of the 2M and 2F adult females showed no significant difference. This result indicated that contiguous male fetuses have a masculinizing effect on the SDN-POA volume of the male. To further examine whether the increment of SDN-POA volume in adulthood was due to exposure to elevated steroid hormones during fetal life, concentrations of testosterone and 17beta-estradiol in the brain were measured with 2M and 2F fetuses during gestation, respectively. On gestation day 21, the concentrations of testosterone and 17beta-estradiol in the brain were significantly higher in the 2M male rats as compared with the 2F male rats. The results suggested that there was a relationship between the fetal intrauterine position, hormone transfer from adjacent fetuses and the SDN-POA volume in adult rat brains.
先前对多胎啮齿动物的研究表明，胎儿在子宫内的位置会影响其后期的解剖结构、生理功能、生殖性能和行为。为了研究子宫内胎儿的位置是否会改变大脑的发育，我们检查了大鼠脑视前区性二态核（SDN-POA）的结构是否与其子宫内位置相符。对成年大鼠大脑切片进行分析，这些成年大鼠在子宫内时处于两个雄性胎儿（2M）之间或两个雌性胎儿（2F）之间，检测其对钙结合蛋白-D28k的免疫反应性，钙结合蛋白-D28k是SDN-POA的标志物。2M成年雄性大鼠的SDN-POA体积大于2F成年雄性大鼠，而2M和2F成年雌性大鼠的SDN-POA体积没有显著差异。这一结果表明，相邻的雄性胎儿对雄性的SDN-POA体积有 masculinizing 作用。为了进一步研究成年期SDN-POA体积的增加是否是由于胎儿期接触了升高的类固醇激素，分别在妊娠期间对2M和2F胎儿的大脑中睾酮和17β-雌二醇的浓度进行了测量。在妊娠第21天，2M雄性大鼠大脑中睾酮和17β-雌二醇的浓度显著高于2F雄性大鼠。结果表明，胎儿在子宫内的位置、相邻胎儿的激素转移与成年大鼠大脑中SDN-POA的体积之间存在关联。 （注：“masculinizing”未找到准确对应中文词汇，暂保留英文）
