The rapid increase in environmental microplastic contamination has raised growing concerns regarding their potential effects on human health, particularly during sensitive developmental periods. Polystyrene microplastics (PS-MPs), among the most prevalent forms, have been detected in food, drinking water, and biological tissues. However, their impact on brain development and long-term neurobiological outcomes remains poorly understood.

This study investigates the consequences of gestational exposure to PS-MPs on hippocampal neurogenesis and neuroinflammatory processes in rat offspring. Pregnant rats received daily, throughout gestation and lactation, 0.5 mL of a pristine polystyrene microplastic suspension containing 0.1 mg of 5 µm PS-MPs by gastric gavage. Offspring were evaluated at distinct developmental stages (G20, PND10, PND21, and PND90). Molecular and protein analyses were performed to assess the expression of key neurogenic markers, pro-inflammatory cytokines, and neurotrophic factors within the hippocampus.

Our findings demonstrate significant developmental stage-dependent alterations in gene and protein expression profiles. Prenatal PS-MP exposure induced a sustained increase in pro-inflammatory markers, particularly IL-6, alongside a marked reduction in DCX expression at adulthood (PND90), suggesting persistent impairment of the hippocampal neurogenic niche. Furthermore, sex-dependent differences were observed, indicating differential vulnerability between males and females.

Collectively, these results provide evidence that gestational exposure to polystyrene microplastics disrupts neurodevelopmental trajectories and promotes long-term neuroinflammatory alterations. This study highlights the potential developmental neurotoxicity of environmental microplastics and underscores the need for further investigation into their impact on brain health.