Objective To investigate the expression of inflanmatory cytokines such as interlukin-1β (IL-1 β),interlukin-6 (IL-6),tumor necrosis factor-α (TNF-α) and intercelluar adhesion molecule-1 (ICAM-1),and explore their relationships with neuronal function score after fluid percussion brain injury in rats.Methods The experimental models were established in 48 adult rats.The water content of edematous brain and the expression of IL-Iβ,IL-6,TNF-α and ICAM-1 were measured with dry-wet measure,immunohistochemistry at 6 h,12 h,24 h,3 d,7 d after operation respectively.Results Compared with animals of shame operation (SO) group,neuronal function score decreased in TBI group from 6h (3.78±0.84),reached to the lowest level at 24h (2.65±0.32),and gradually increased at 3d (4.75±0.71).IL-6,IL-1β,TNF-α and ICAM-limmunoreactive expression increased from 6h,reached its maxmum at 24h,lasted to 3th day,and began to decrease at 7d.The linear regression analysis indicated that expression of IL-1β,IL-6,TNF-α and ICAM-1 had negative correlations with change of neuronal function score(r=-0.912,r=-0.892,r=-0.794,r=-0.887 respectively,P＜0.05).Conclusion IL-6,IL-1β,TNF-α and ICAM-1 expression is upregulated following fluid percussion injury in rats,and shows negative correlations with neuronal function score.The possible mechanisms is that inflammatory cytokines are involved in nerve function impairment by inducing secondary brain injury.