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Neonatal meningitis is an illness characterized by inflammation of the meninges and occurring within the birth and the first 28 days of life. Invasive infection by Streptococcus pneumoniae, meningitis and sepsis, in neonate is associated with prolonged rupture of membranes; maternal colonization/illness, prematurity, high mortality and 50% of cases have some form of disability. For this purpose, we measured brain levels of TNF-α, IL-1β, IL-6, IL-10, CINC-1, oxidative damage, enzymatic defense activity and the blood–brain barrier (BBB) integrity in neonatal Wistar rats submitted to pneumococcal meningitis. The cytokines increased prior to the BBB breakdown and this breakdown occurred in the hippocampus at 18h and in the cortex at 12h after pneumococcal meningitis induction. The time-dependent association between the complex interactions among cytokines, chemokine may be responsible for the BBB breakdown and neonatal pneumococcal severity.

Experimental autoimmune encephalomyelitis (EAE) is a condition induced in some susceptible species to the study of multiple sclerosis (MS). The platelet activating factor (PAF) is an important mediator of immune responses and seems to be involved in MS. However, the participation of PAF in EAE and MS remains controversial. Thus, in this study, we aimed to evaluate the role of PAF receptor in the pathogenesis of EAE. EAE was induced using an emulsion containing MOG(35-55). EAE-induced PAF receptor knock out (PAFR(-/-)) mice presented milder disease when compared to C57BL/6 wild type (WT) animals. PAFR(-/-) animals had lower inflammatory infiltrates in central nervous system (CNS) tissue when compared to WT mice. However, intravital microscopy in cerebral microvasculature revealed similar levels of rolling and adhering leukocytes in both WT and PAFR(-/-) mice. Interleukine (IL)-17 and chemokines C-C motif legends (CCL)2 and CCL5 were significantly lower in PAFR(-/-) mice when compared to WT mice. Brain infiltrating cluster of differentiation (CD)4(+) leukocytes and IL-17(+) leukocytes was diminished in PAFR(-/-) when compared to WT mice. Taken together, our results suggest that PAF receptor is important in the induction and development of EAE, although it has no influence in rolling and adhesion steps of cell recruitment. The absence of PAF receptor results in milder disease by altering the type of inflammatory mediators and cells that are present in CNS tissue.