Effects of the autoimmune uterine/maternal environment upon cortical ectopias, behavior and autoimmunity

Abstract

NZB and BXSB mice develop autoimmune disease and learn poorly on avoidance tasks. In addition, many of these mice have ectopic collections of neurons, which occur prenatally, in layer I of the cerebral neocortex. The purpose of these experiments was to evaluate the contribution of the uterine/maternal environment upon these variables by transferring fertilized ova to an autoimmune or a non-autoimmune maternal host. In Experiment 1 fertilized DBA ova were transferred into the uteri of BXSB maternal recipients. Later, these animals and conventionally reared DBAs were tested for paw preference, swimming rotation, water escape learning, and shuttlebox avoidance learning. Blood was taken for measurement of immune parameters, and their brains were examined for cortical ectopias. As compared to conventional DBAs, the ova transfer mice had greater amounts of anti-dsDNA autoantibodies, poorer avoidance learning, and poorer water escape learning; in addition, the females had greater paw asymmetry. There was only 1 ectopia in the 81 ova transfer animals, and none in the 78 control mice. In Experiment 2 fertilized NZB ova were transferred into the uteri of non-autoimmune hybrid females and the same procedures were followed as in Experiment 1. Ova transfer mice had lesser amounts of anti-dsDNA autoantibodies, better avoidance learning scores, and females had less paw asymmetry; in addition, within the ova transfer group males were clockwise swimmers whereas females swam counterclockwise. There were 4 ectopics out of 17 ova transfer mice (23.5%), which did not differ from the 40.5% of the control group. In both experiments the uterine environment did not affect the occurrence of ectopias. In contrast, rearing mice in an autoimmune uterine/maternal environment resulted in decrements in avoidance learning and water escape learning, greater paw asymmetry for females, and increased amounts of anti-dsDNA autoantibodies. The dissociation of ectopias from avoidance learning, paw asymmetry and the anti-dsDNA measure indicates that separate mechanisms are involved. The findings suggest a genetic mechanism for the occurrence of ectopias and an epigenetic immune-associated uterine/maternal mechanism for the behavioral changes.