Prenatal Zinc Supplementation Ameliorates Hippocampal Astrocytes Activation and Inflammatory Cytokines Expression Induced by Lipopolysaccharide in a Rat Model of Maternal Immune Activation.

Abstract

Introduction: Evidence suggests that gestational exposure to Lipopolysaccharide (LPS) results in fetal zinc deficiency and eventually neurodevelopmental abnormalities. In this study, we utilized a rat model of Maternal Immune Activation (MIA) to investigate the possible neuroprotective effects of zinc supplementation during pregnancy on hippocampal astrocytes activation as well as inflammatory cytokines expression in adult offspring.

Methods: Pregnant rats received intraperitoneal injections of either LPS (0.5 mg/kg) or saline on Gestational Days (GD) 15 and 16, and orally gavaged with zinc sulfate (30 mg/kg) during pregnancy. Astrocyte density and histological assessment were evaluated in the hippocampus of adult offspring on Postnatal Days (PND) 60 to 62. Also, the mRNA levels of IL-6, TNF-α, IL-1β, NF-κB, and GFAP were measured using qPCR analysis.

Results: Prenatal exposure to LPS resulted in upregulated expression levels of IL-6, TNF-α, NF-κB, and GFAP in the hippocampus of adult pups. Moreover, the offspring from the LPS group showed an increased astrocyte density in the CA1 region with no histological alterations in CA1 and CA3 areas. However, maternal zinc supplementation ameliorated the LPS-induced inflammatory alterations.

Conclusion: This study supports the premise that zinc supplementation during pregnancy might be an early treatment option to inhibit hippocampal inflammation induced by the maternal immune response to infectious agents.

Highlights: Maternal immune activation induced mild hippocampal inflammation in adult offspring.Zinc supplementation suppressed LPS-induced hippocampal inflammation in offspring.Zinc might be an early therapeutic option to inhibit neurodevelopmental impairments.

Plain language summary: Schizophrenia is a chronic and disabling psychiatric disorder, affecting an estimated one percent of the world's population. To date, the biological mechanisms underlying this mental disorder remain largely elusive, however, research has demonstrated the involvement of both genetic and environmental factors. Of environmental factors, gestational exposure to rubella, influenza, and genital-reproductive infections have gained particular interest among researchers. Based on this evidence, in the present study, we used an animal model of schizophrenia and showed the beneficial effect of zinc supplementation during pregnancy to protect against LPS-induced inflammation in the hippocampus of adult offspring. Collectively, our study provides support for the premise that early treatment might be a suitable option to prevent schizophrenia risk in progeny.