Lung development and postnatal survival for rats exposed in utero to a high-boiling coal liquid.

Previous studies performed in this laboratory indicated that exposure of rat fetuses to high-boiling coal liquids from 12-14 days of gestation (dg) induced a number of major malformations, including cleft palate, diaphragmatic hernia and small lungs. The study reported here was designed to determine postnatal viability and development of survivors following in utero exposure to Harmarville process solvent (HPS), a wide-boiling-range (150 to greater than 455 degrees C) coal liquid. For this study, 0.74 g kg-1 of the coal liquid was administered (by intragastric intubation) to rats from 12 to 14 dg. Offspring were evaluated for postnatal survival, growth and lung and thymus weights. Randomly selected pups from control and treated litters were killed and necropsied at 1, 3, 7 and 21 days postpartum. In addition, data for control pups were obtained at 0.25 and 0.5 days postpartum for comparison with body, lung and thymus weights of pups that died during this interval. Fifty-four per cent of the exposed pups and 9% of the control pups died between birth and 3 days postpartum. Of the treated pups that died, 10% (6/5; pups/litters) had cleft palate, 27% (17/9) had small lungs and 33% (21/8) had both cleft palate and small lungs. No gross malformations were observed in the remaining 30% of the dead pups. Microscopic examination of lungs from HPS-treated pups revealed no evident histological abnormalities. Body, lung and thymus weights for treated animals that died were significantly less than those of controls.(ABSTRACT TRUNCATED AT 250 WORDS)