Prenatal lipopolysaccharide increases maternal behavior, decreases maternal odor preference, and induces lipopolysaccharide hyporesponsiveness

The present study investigated whether late maternal inflammation disrupts the mother/pup interaction, resulting in long-lasting effects on pup behavior and alterations in biological pathways, thereby programming prepubertal behavior and the pups' inflammatory responses after bacterial endotoxin treatment. Female rats received 100 μg/kg lipopolysaccharide (LPS) or .9% saline solution on gestation day 18. Reproductive performance was observed at birth. On lactation days (LD) 5 and LD 6, respectively, maternal behavior and maternal aggressive behavior were assessed. In pups, maternal odor preference on LD 7, open field behavior on LD 21, and serum tumor necrosis factor α (TNF-α) levels after LPS challenge on LD 21 were investigated. The results showed that prenatal LPS exposure improved maternal care and reduced maternal aggressive behavior but did not alter maternal reproductive performance. Male offspring exhibited increased body weights at birth and reduced maternal odor preference. Lipopolysaccharide challenge increased the duration of immobility in the open field and induced a slight increase in serum TNF-α levels. Prenatal exposure to LPS during late pregnancy improved maternal care, reduced maternal olfactory preference, and induced TNF-α hyporesponsiveness to a single dose of LPS in pups.