Studies on hypoxia--I. Gross and histologic influences of maternal anoxia upon the developing rat foetus

Abstract

As the first communication of a series to be reported, this article represents the result of a survey work which was designed to serve as the basis for further experimentation on the subject. Effects of maternal anoxia upon the developing rat foetus were studied by subjecting pregnant Sprague-Dawley rats to an atmosphere of 100 per cent nitrogen for a total of 18 min on the 10th, 14th, 17th or 20th day of gestation and their offspring were then evaluated morphologically, radiographically, and histologically. All defects of skeletal morphology were found in newborns that were treated on the 10th day of gestation. The animals treated on the 20th day of gestation exhibited a consistent retardation in eruption of the molars. Histologically, a serious lag in the differentiation of epidermal and connective tissue cells was observed in animals subjected to anoxia on the 10th day, while an engorgement of the blood vessels was apparent in animals which were subjected to anoxia on the 20th day. These changes are discussed in relation to possible biochemical and physiologic effects of anoxia on these cells.