Age-related mortality and adherent splenic cell mediator production to endotoxin in the rat

Rat neonatal mortality to endotoxin and age-related changes in adherent splenic cell mediator production in vitro were investigated. Neonatal rat pups, 24, 48, 96, and 216 h old or maternal adult rats were administered doses of Salmonella enteritidis endotoxin, (.024 mg to 7.5 mg/kg) and survival was monitored for 72 h. Mortality demonstrated high sensitivity (p < .05) of neonates to endotoxin (particularly 24 h old neonates). Endotoxin administration .6 mg/kg intracardiac) produced a 100% lethality in 24 h neonates (p < .05) versus 23% or less lethality in the 48 to 216 h old age group. Endotoxin administration (.4 mg/kg subcutaneous) also produced 100% lethality in 24 h old neonates compared with reduced mortality versus older age groups. Endotoxin in vitro stimulated (p < .05) adherent splenic cell thromboxane (TX)B2, interleukin-6, and nitrite production in most groups. Splenic cell nitrite production was higher (p > .05) in the 24 h old neonates, but lower in 48 h and 96 h old groups compared with maternal adults. Splenic cell TXB2 production was higher (p < .05) in the 24 h and 216 h old neonates relative to maternal adults. In conclusion, 24 h old rat pups are more susceptible to endotoxic shock than older age groups and adults, and exhibit altered production of the cellular mediators nitric oxide and TXB2.