SELECTIVE CHEMOKINE MESSENGER-RNA ACCUMULATION IN THE RAT SPINAL-CORDAFTER CONTUSION INJURY

Following traumatic injury to the spinal cord, hematogenous inflammato ry cells including neutrophils, monocytes, and lymphocytes infiltrate the lesion in a distinct temporal sequence. To examine potential mecha nisms for their recruitment, we measured chemokine mRNAs in the contus ed rat spinal cord, using specific and sensitive reverse transcriptase polymerase chain reaction IRT-PCR) dot-blot hybridization assays. The neutrophil chemoattractant GRO-alpha was 30-fold higher than control values at 6 hr postinjury and decayed rapidly thereafter. LIS, a highl y related alpha-chemokine, also was elevated early postinjury. Monocyt e chemoattractant peptide (MCP)-1 and MCP-5 mRNAs, potent chemoattract ants for monocytes, were significantly elevated at the lesion epicente r at 12 and 24 hr postinjury and declined thereafter. Interferon-gamma -inducible protein, 10 kDa (IP-10), chemoattractant towards activated T-lymphocytes, was significantly elevated at 6 and 12 hr postinjury. T he dendritic cell chemoattractant MIP-3 alpha also mas increased, perh aps contributing to the development of T-cell autoreactivity to neural components after spinal cord injury (SCI) in rats. Other beta-chemoki nes, including MIP-1 alpha and RANTES (regulated on expression normal T-cell expressed and secreted), were minimally affected by SCI. Expres sion of chemokines, therefore, directly precedes the influx of target neutrophils, monocytes, and T-cells into the spinal cord postinjury; a s noted previously. Thus, selective chemokine expression may be integr al to inflammatory processes within the injured spinal cord as a mecha nism of recruitment for circulating leukocytes, J, Neurosci, Res. 53:3 68-376, 1998. (C) 1998 Wiley-Liss, Inc.