Status of proinflammatory and anti-inflammatory cytokines in different brain regions of a rat model of Japanese encephalitis

Abstract

Objectives This study evaluated cytokines and chemokine in different regions of the rat brain at different time points following Japanese encephalitis virus (JEV) infection. Design Twelve-day-old Wistar rats were infected by intracerebral inoculation of 3×10 6plaque-forming units of JEV 78668A strain. Expression of cytokines and chemokine was assayed using cytokine bead array in different regions of the brain at 3, 6, 10 and 20 days post-inoculation (dpi). Pathological changes including immunohistochemistry for JEV antigen were observed. Results The cytokine levels were increased in the acute stage and declined on follow-up. In the acute stage (6 dpi), the levels of TNF-α, IFN-γ,IL-6 and IL-10 weremaximum in the cortex, whereas the level of IL-4 was maximum in the striatum. Lower levels of these cytokines were observed in mid-brain and thalamus compared to other regions studied. Maximum expression of JEV antigen and histopathological changes aswell as cytokines and chemokine were observed at 6 dpi in all the brain regions studied, but declined thereafter. Conclusion This experimental study revealed maximum expression of cytokines and chemokine at 6 dpi of JEV infection which corresponded with histopathological changes in different brain regions. Copyright © Springer Basel AG 2011.