Chapin R E, Gulati D K, Barnes L H, Teague J L
Developmental and Reproductive Toxicology Group, National Toxicology Program, NIEHS, Research Triangle Park, North Carolina 27709.
Fundam Appl Toxicol. 1993 Jan;20(1):23-9. doi: 10.1006/faat.1993.1003.
Although it is known that severe feed restriction (FR) and weight reduction (to 50-60% of control values) will sharply impair rat reproduction, few data exist on the effects of less severe body weight reduction. In the present studies, adult Sprague-Dawley rats were feed restricted and maintained at 90, 80, and 70% of control body weight (CBW) for up to 17 weeks. In females, this treatment had no effect on fertility or total number of implants per dam, but transiently increased the length of the estrous cycle and decreased by 20% the number of corpora lutea in the 70% CBW females. Ovary weight at necropsy was decreased only in the 70% CBW group. Liver and kidney weights varied with body weight. In males, fertility was not affected when they were mated to nonrestricted females. While prostate and seminal vesicles weight varied with body weight, testis and epididymis weights were unchanged by any degree of FR, as were the number of sperm in the cauda epididymis and the number of homogenization-resistant spermatids in the testis. The percentage motile sperm was slightly decreased at all levels of FR. These data show that the Sprague-Dawley rat is largely resistant to adverse reproductive changes caused by feed restriction to 70% CBW. These data should be of use in interpreting changes seen in toxicity studies that produce weight-reduce Sprague-Dawley rats.
虽然已知严重的饲料限制（FR）和体重减轻（降至对照值的50 - 60%）会严重损害大鼠的繁殖能力，但关于不太严重的体重减轻的影响的数据却很少。在本研究中，成年斯普拉格 - 道利大鼠被限制喂食，并维持在对照体重（CBW）的90%、80%和70%长达17周。对于雌性大鼠，这种处理对生育能力或每只母鼠的着床总数没有影响，但会短暂增加发情周期的长度，并且使体重为对照体重70%的雌性大鼠的黄体数量减少20%。尸检时卵巢重量仅在体重为对照体重70%的组中降低。肝脏和肾脏重量随体重变化。对于雄性大鼠，当它们与未受限制的雌性大鼠交配时，生育能力不受影响。虽然前列腺和精囊重量随体重变化，但任何程度的饲料限制都不会改变睾丸和附睾的重量，附睾尾部的精子数量和睾丸中抗均质化的精子细胞数量也不受影响。在所有饲料限制水平下，活动精子的百分比略有下降。这些数据表明，斯普拉格 - 道利大鼠对因饲料限制至对照体重70%而引起的不良生殖变化具有很大的抵抗力。这些数据应有助于解释在导致斯普拉格 - 道利大鼠体重减轻的毒性研究中所观察到的变化。
