Intracerebral lipopolysaccharide induces neuroinflammatory change and augmented brain injury in growth-restricted neonatal rats

INTRODUCTION: Intrauterine growth-restriction (IUGR) alters fetal development and is associated with neurodevelopmental abnormalities. We hypothesized that growth-restriction from reduced intrauterine perfusion would predispose neonatal rats to subsequent inflammatory brain injury. METHODS: In the current study, IUGR was achieved by induced placental insufficiency in pregnant rats at 14 days of gestation. IUGR offspring and sham-operated control pups were subsequently injected with intracerebral lipopolysaccharide (LPS) as a model of PVL (perventricular leukomalacia). RESULTS: LPS similarly elevates proinflammatory cytokines in the brains of both IUGR and control rat pups. However, the chemokines cytokine-induced neutrophil chemoattractant-1 (CINC-1) and macrophage chemoattractant protein-1 (MCP-1), as well as microglia activation, were significantly higher in LPS-treated IUGR rat pups compared to LPS-treated controls. In addition to the unique brain inflammatory response, IUGR rat pups demonstrated enhanced brain damage with an increased number of apoptotic cells, larger lateral ventricular size, and more severe impairment of myelination. DISCUSSION: This study provides evidence that placental insufficiency may sensitize the innate immune system in the immature brain, and reveals a possible link between brain inflammation and injury.