Antagonism of leukocyte adherence by synthetic fibronectin peptide V in a rat model of transient focal cerebral ischemia

OBJECTIVE: Activated polymorphonuclear leukocytes (PMNs) seem to be directly involved in potentiating ischemic brain injury. Recent work in our laboratory demonstrated that synthetic fibronectin peptides significantly inhibit PMN accumulation in ischemic tissue, reduce the size of infarction, and reduce neurological dysfunction after transient focal cerebral ischemia in rats. The purpose of this study was to examine any dose-related effects (Experiment 1) and the optimal timing of the administration (Experiment 2) of synthetic fibronectin peptide V (FN-C/H-V) to further substantiate the role of the peptide in ameliorating cerebral ischemic damage. METHODS: Fifty-six animals were included in the study. We evaluated the efficacy of FN-C/H-V on PMN accumulation in ischemic tissue, infarct size, and neurological outcomes in rats subjected to 1 hour of cerebral ischemia and 48 hours of reperfusion. RESULTS: In Experiment 1, the animals receiving FN-C/H-V at a dose of 10 to 15 mg/kg of body weight per injection showed significant reduction of PMN accumulation, reduction of infarct size, and improvement of neurological outcomes at 48 hours after reperfusion compared to untreated animals (P < 0.05). In Experiment 2, the animals receiving FN-C/H-V within 3 hours after reperfusion also showed significantly better results than untreated animals (P < 0.05). Despite the treatment delay, the administration of FN-C/H-V inhibited PMN accumulation after reperfusion but did not reduce the size of infarction when administered 6 hours after reperfusion. CONCLUSION: These data suggest that relatively late postischemic administration of FN-C/H-V is effective in brain protection after ischemia/reperfusion.