Maternal deprivation and early weaning modulate experimental allergic encephalomyelitis in the rat.

The present experiment deals with the effect of maternal deprivation (MD) and early weaning (EW) on the development and course of experimental allergic encephalomyelitis (EAE) in Dark August (DA) rats. Five litters (five to nine pups per liter) were subjected to MD (4 h daily) from Day 1 until Day 28. EW rats were weaned on Day 15 (EW-15, five litters) or Day 21 (EW-21, four litters). Control rats and MD rats were weaned on Day 28. At the age of 8 weeks, rats were immunized with guinea pig spinal cord in complete Freund's adjuvant and clinical signs of EAE were recorded daily. On Day 18 after immunization, rats were bled and sacrificed. Brain and spinal cord were examined histologically for EAE lesions. Serum anti-rat myelin basic protein (MBP) antibodies were detected by ELISA. MD female rats exhibited suppression of neurological and histological signs of EAE in comparison with control rats. MD and control females showed elevated anti-MBP antibody level compared to MD and control males. EW-15 female rats demonstrated potentiation of neurological signs of EAE compared to control females. EW-21 females developed more severe clinical signs and histological lesions compared to control females. These results show that neonatal experiences, such as maternal deprivation and early weaning, influence the development of EAE in adult DA rats.