RESUMO
Leukocyte infiltration is viewed as a pharmacological target in cerebral ischemia. We previously reported that reparixin, a CXCL8 receptor blocker that inhibits neutrophil infiltration, and related molecules can reduce infarct size in a rat model of transient middle cerebral artery occlusion (MCAO). The study aims were to compare the effects of reparixin in transient and permanent MCAO using varied treatment schedules and therapeutic windows to evaluate effects on long-term neurological deficits and late inflammatory response. Reparixin, administered for 1 to 3 days, 3.5 to 6 h after MCAO, ameliorates neurological function recovery and inhibits long-term inflammation. The infarct size reduction at 24 h, evaluated by TTC staining, is more pronounced in transient MCAO. MRI analysis identified a decrease in the progression of infarct size by reparixin that was more evident at 48 h in permanent MCAO, and was associated with a significantly improved recovery from long-term neurological deficits.
Assuntos
Isquemia Encefálica/tratamento farmacológico , Inflamação/tratamento farmacológico , Ataque Isquêmico Transitório/tratamento farmacológico , Receptores de Interleucina-8/antagonistas & inibidores , Sulfonamidas/farmacologia , Animais , Isquemia Encefálica/imunologia , Isquemia Encefálica/metabolismo , Isquemia Encefálica/patologia , Esquema de Medicação , Imuno-Histoquímica , Infarto da Artéria Cerebral Média/etiologia , Infarto da Artéria Cerebral Média/cirurgia , Ataque Isquêmico Transitório/etiologia , Ataque Isquêmico Transitório/patologia , Masculino , Fármacos Neuroprotetores/farmacologia , Ratos , Ratos EndogâmicosRESUMO
The chemokine receptors CXCR1 and CXCR2 present on polymorphonuclear neutrophils (PMN), bind the chemokine CXC ligand 8 (CXCL8)/interleukin-8 (IL-8), and have a key role in PMN recruitment in inflammation. Based on the structure of reparixin, a small-molecular-weight allosteric inhibitor of CXCR1, we designed a dual inhibitor of CXCR1 and CXCR2 with a longer in vivo half-life, DF2156A. This molecule inhibited human and rat PMN migration in response to CXCR1 and CXCR2 ligands and showed an elimination half-life following i.v. administration, of 19 hours. In a rat model of cerebral ischemia/reperfusion induced by temporary (90 min) middle cerebral artery (MCA) occlusion, DF2156A (8 mg-kg, i.v., at the time of reperfusion) decreased the PMN infiltrate, infarct size and significantly improved neurological function. These results indicate that CXCR1/CXCR2 and their ligands have a role in the inflammatory component of cerebral ischemia, and that these pathways represent an important pharmacological target.
