Jensh R P, Brent R L
Department of Anatomy, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania 19107.
Teratology. 1988 Nov;38(5):443-9. doi: 10.1002/tera.1420380507.
It is evident that significant permanent tissue hypoplasia can be produced following radiation exposure late in fetal development. Because two organs, brain and testes, are developmentally and functionally interrelated, it was of interest to determine whether fetal testicular hypoplasia was a primary or a secondary effect of fetal brain irradiation. Twenty-four pregnant Wistar strain rats were randomly assigned to one of four groups, and a laparotomy was performed on day 18 of gestation. The fetuses received sham irradiation, whole body irradiation, or only head/thorax or pelvic body irradiation at a dosage level of 1.5 Gy. Mothers were allowed to deliver and raise their offspring until postnatal day 30, when the offspring were weaned. At 60 days of age, 74 male offspring were allowed to mate with colony control females of similar age until successful insemination or until the males reached 90 days of age, when they were killed. Testes were weighed and processed for histologic examination. Direct radiation of testes, due to whole body or pelvic exposure, resulted in testicular growth retardation and significantly reduced spermatogenesis. Breeding activity of the males and the percent of positive inseminations were also slightly reduced. However, a significant percentage of male offspring receiving direct testicular radiation did produce offspring. Head/thorax-only irradiation did not adversely affect testicular growth or spermatogenesis. Therefore, the use of histologic analysis as the sole determinant of infertility may be misleading. This study indicates that testicular growth retardation and an increased infertility rate result from direct prenatal exposure of rat testes to X-radiation and are not necessarily mediated via X-irradiation effects on the central nervous system.
显然，在胎儿发育后期受到辐射后，可产生显著的永久性组织发育不全。由于脑和睾丸这两个器官在发育和功能上相互关联，因此确定胎儿睾丸发育不全是胎儿脑部照射的原发性还是继发性效应很有意义。将24只怀孕的Wistar品系大鼠随机分为四组之一，并在妊娠第18天进行剖腹手术。胎儿接受假照射、全身照射，或仅头部/胸部或骨盆部位照射，剂量为1.5 Gy。让母鼠分娩并抚养其后代至出生后第30天断奶。在60日龄时，让74只雄性后代与年龄相似的群体对照雌性交配，直至成功授精或直至雄性达到90日龄后处死。称取睾丸重量并进行组织学检查。由于全身或骨盆暴露而对睾丸进行直接辐射，导致睾丸生长迟缓并显著降低精子发生。雄性的繁殖活动和阳性授精的百分比也略有降低。然而，接受直接睾丸辐射的雄性后代中有很大比例确实产生了后代。仅头部/胸部照射对睾丸生长或精子发生没有不利影响。因此，将组织学分析作为不育的唯一决定因素可能会产生误导。本研究表明，大鼠睾丸在产前直接暴露于X射线会导致睾丸生长迟缓以及不育率增加，且不一定是通过对中枢神经系统的X射线照射效应介导的。
