Development of explanted rat fetuses in hyperbaric oxygen

Raising the oxygen pressure of the culture chamber to 2 or 3 atmospheres improved the development in static serum of rat embryos explanted at 11.5 days' gestation, but the final stage attained (35–37 somites) was less than that of embryos in circulating serum equilibrated with oxygen at normal pressure (40–45 somites). Hyperbaric oxygen appeared to be of most value for the culture of embryos explanted at 12.5 days' gestation (about 40 somites). These developed well to 50–55 somites in circulating serum in oxygen at two atmospheres pressure, but showed very little development in oxygen at normal pressure. The high oxygen concentrations were harmful to the yolk sac, and it was not possible to extend development in culture beyond 50–55 somites.