Vertebral Malformation in the Mouse Foetus Caused by Maternal Hypoxia During Early Stages

INTRODUCTION M A N Y experiments have recently been conducted to investigate the effects of oxygen deficiency upon embryonic development. Embryos offish, amphibia and birds have most frequently been used. Of all these experiments, those of Stockard (1921), of Biichner and his co-workers, and particularly of Rubsaamen (1952), were the most striking. Experiments employing mammals have been very few. Subjecting mice to hypoxia in the early stages of pregnancy Ingalls, Curley & Prindle (1950) could analyse the developmental disturbances observable in the offspring. Werthemann, Reiniger & Thoelen (1950) and Werthemann & Reiniger (1950) used the rabbit and rat in similar experiments. Murakami, Kameyama & Kato (1956) exposed pregnant mice to hypoxia on the eighth day of pregnancy and observed malformation of the central nervous system. Vertebrae were found to be malformed by Ingalls & Curley (1957) and by Degenhardt (1954, 1959) after oxygen deficiency. Badtke, Degenhardt & Lund (1959) also described cranio-facial dysplasia in the progeny of rabbits treated with hypoxia. In the work to be reported here mice were exposed to hypoxia in the early stages of pregnancy and frequent malformations of the vertebrae were induced in the foetus. Analysis of the results indicates a close relationship between the developmental stage at which embryos were treated and the cranio-caudal level of the malformation. The later the treatment, the more caudal was the site of the malformation, confirming the findings of Ingalls et al. and Degenhardt.