Regulation of chemokines and chemokine receptors after experimental closed head injury

The expression of the chemokines macrophage inflammatory protein (MIP)-2 and MIP-1 alpha and of their receptors CXCR2 and CCR5 was assessed in wild type (WT) and TNF/lymphotoxin-alpha knockout (TNF/LT-alpha-/-) mice subjected to closed head injury (CHI). At 4 h after trauma intracerebral MIP-2 and MIP-1 alpha levels were increased in both groups with MIP-2 concentrations being significantly higher in WT than in TNF/LT-alpha-/- animals (p<0.05). Thereafter, MIP-2 production declined rapidly, whereas MIP-1 remained elevated for 7 days. Expression of CXCR2 was confined to astrocytes and increased dramatically within 24 h in both mouse types. Contrarily, CCR5 expression remained constitutively low and was mainly localized to microglia. These results show that after CHI, chemokines and their receptors are regulated differentially and with independent kinetics. NeuroReport 12:2059-2064 (C) 2001 Lippincott Williams & Wilkins.