Effects of hyperthermia on rat embryos in culture

Abstract

TEMPORARY elevation of the body temperature, resulting from climatic influences or infection, occurs in many mammals. Such hyperthermia is often harmless, but in the pregnant female it may be teratogenic, with particularly damaging effects on the brain of the developing embryo. The studies that have been made on experimentally induced hyperthermia and teratogenesis in animals are reviewed in ref. 1 and suggest that hyperthermia may also be teratogenic in man. The methods used to raise the temperature in experimental animals have included incubation of the whole animal², injection of foreign protein³, short-wave diathermy⁴, immersion of the uterus in heated saline^5,6, and microwave radiation of the uterus⁷. In most of these experiments the period of exposure to high temperature (often only 40–60 min) was limited by the tolerance of the animal and the need to avoid excessive resorption of the embryos. The temperature experienced by the embryos usually varied during treatment and could not be controlled precisely.