Cytokine-induced neutrophil chemoattractant mRNA expressed in cerebral ischemia.

Cytokine-induced neutrophil chemoattractant (CINC), originally identified as a chemoattractant in rat kidney epithelial cells, is related to human 'gro' and murine 'KC'. The proteins encoded by these genes belong to the chemokine alpha superfamily, most of which have neutrophil chemotactic activity. Since brain chemokines may play a significant role in neutrophil accumulation in cerebral ischemia which can contribute to the extent of tissue injury in stroke, we examined the expression of CINC mRNA in the cerebral cortex of rats subjected to focal cerebral ischemia induced by middle cerebral artery occlusion (MCAO). Significant CINC mRNA expression was observed in the ipsilateral (ischemic) cortex from 6 h (17.3 +/- 3.7%, n = 6, P < 0.05) to 24 h (32.1 +/- 3.7%, n = 5, P < 0.01) with a peak at 12 h (43.9 +/- 3.7%, n = 6, P < 0.01) after MCAO. Five days post-MCAO, CINC mRNA levels were no longer elevated. No significant CINC mRNA expression was observed in the contralateral (control) cortex. These studies suggest that message for the neutrophil chemoattractant CINC is induced early in brain tissue subjected to ischemia, and therefore supports the possibility that brain-derived chemokines support the infiltration of circulating inflammatory cells following focal stroke.