Light and electron microscopic study of fetal lung following maternal exposure to methylmercuric chloride

Varying dose levels of methylmercuric chloride (MMC), 1000 ppm (5 mg through 15 mg/kg of body weight), were administered via an intragastric tube to pregnant ICR Swiss/Webster mice on day 9 of gestation. The animals were killed on gestational day 18 and the fetuses removed. Fetal lung sections were processed for light and electron microscopy. A group of animals treated with physiological saline in a similar manner served as the controls. The fetal lungs from treated animals were hypoplastic and retarded in development. The severity of pulmonary changes increased with the dose-levels of MMC. Vacuolation and lysis of mitochondria were seen in fetal lungs. Mitochondrial damage increased in severity with dose-level of methylmercuric chloride.