Maternal stress during pregnancy is associated with increased risk of psychiatric disorders in offspring, but embryonic brain mechanisms disrupted by prenatal stress are not fully understood. Our lab has shown that prenatal stress delays inhibitory neural progenitor migration. Here, we investigated redox dysregulation as a mechanism for embryonic cortical interneuron migration delay, utilizing direct manipulation of pro- and anti-oxidants and a mouse model of maternal repetitive restraint stress starting on embryonic day 12. Time-lapse, live-imaging of migrating GABAergic interneurons showed that normal tangential migration of inhibitory progenitor cells was disrupted by the pro-oxidant, hydrogen peroxide. Interneuron migration was also delayed by in utero intracerebroventricular rotenone. Prenatal stress altered glutathione levels and induced changes in both activity of antioxidant enzymes and expression of redox-related genes in the embryonic forebrain. Assessment of dihydroethidium (DHE) fluorescence after prenatal stress in ganglionic eminence, the source of migrating interneurons, showed increased levels of DHE oxidation. Maternal antioxidants (N-acetylcysteine and astaxanthin) normalized levels of DHE oxidation in ganglionic eminence, and ameliorated the migration delay caused by prenatal stress.
In adult male offspring, prenatally-stressed mice exhibited anxiety-like behavior on the elevated plus maze, impaired motor learning on the rotarod, cognitive flexibility on the water T-maze task, and deficits in sensorimotor gating in the pre-pulse inhibition task. Prenatally-stressed adult female offspring showed anxiety-like behavior, deficits in sociability and impaired motor learning. Maternal antioxidants prevented anxiety-like behaviors and improved sensorimotor gating in both sexes, and improved habitual learning and cognitive flexibility in adult female mice. Lastly, prenatal stress led to increases in PV+/GAD67+ cell ratios in mFC in male mice, but decreases in female mice, and antioxidant treatments eliminated those differences. Hippocampal GAD67+ cell densities were reduced by prenatal stress and restored by astaxanthin in male mice, and PV+/GAD67+ cell ratio was reduced by prenatal stress and partially restored by N-acetylcysteine in female mice. GAD67+ cell densities across regions correlated significantly with anxiety-like behavior in both male and female mice and social behavior in female mice. Through convergent redox manipulations, delayed interneuron migration after prenatal stress was found to critically involve redox dysregulation. Redox biology during prenatal periods may be a target for protecting brain development.