Blockade of CXCR1/2 chemokine receptors protects against brain damage in ischemic stroke in mice

Abstract

OBJECTIVE:Ischemic stroke may result from transient or permanent reductions of regional cerebral blood flow. Polymorphonuclear neutrophils have been described as the earliest inflammatory cells to arrive in ischemic tissue. CXCR1/2 receptors are involved in the recruitment of these cells. However, the contribution of these chemokine receptors during transient brain ischemia in mice remains poorly understood. In this work, we investigated the effects of reparixin, an allosteric antagonist of CXCR1/2 receptors, in a model of middle cerebral artery occlusion and reperfusion in mice.METHODS:C57BL/6J male mice treated with reparixin or vehicle were subjected to a middle cerebral artery occlusion procedure 1 h after the treatment. Ninety minutes after ischemia induction, the monofilament that prevented blood flow was removed. Twenty-four hours after the reperfusion procedure, behavioral changes, including motor signs, were analyzed with the SmithKline/Harwell/Imperial College/Royal Hospital/Phenotype Assessment (SHIRPA) battery. The animals were sacrificed, and brain tissue was removed for histological and biochemical analyses. Histological sections were stained with hematoxylin and eosin, neutrophil infiltration was estimated by myeloperoxidase activity and the inflammatory cytokine IL-1β was measured by ELISA.RESULTS:Pre-treatment with reparixin reduced the motor deficits observed in this model of ischemia and reperfusion. Myeloperoxidase activity and IL-1β were reduced in the reparixin-treated group. Histological analysis revealed that ischemic injury was also attenuated by reparixin pre-treatment.CONCLUSIONS:Our results suggest that the blockade of the CXCR1/2 receptors by reparixin promotes neuroprotective effects by reducing the levels of polymorphonuclear infiltration in the brain and the tissue damage associated with middle cerebral artery occlusion and reperfusion.

Memory deficit associated with increased brain proinflammatory cytokine levels and neurodegeneration in acute ischemic stroke

“…cortex 3,4 . Interestingly, reperfusion may paradoxically exacerbate brain injury, by involvement of neutrophils, glial reaction, cytokine and chemokine production 5,6,7 . Cognitive deficits have often been reported following brain ischemia, being memory the most affected domain, followed by attention and executive function 8,9 .…”

“…We measured the expression of the chemokine CXCL1, the rodent homolog of human IL-8, which is chemoattractant for neutrophils. Neutrophils are the first inflammatory cells in the ischemic tissue and during reperfusion contribute to expansion of brain injury by production of radical oxygen species, proteinases and cytokines 7,10 . We previously demonstrated that blockade of CXCR1/2 receptors by reparixin promoted neuroprotective effects by reducing the levels of neutrophil infiltration and tissue damage in the brain after cerebral occlusion and reperfusion in mice 7 .…”

“…Neutrophils are the first inflammatory cells in the ischemic tissue and during reperfusion contribute to expansion of brain injury by production of radical oxygen species, proteinases and cytokines 7,10 . We previously demonstrated that blockade of CXCR1/2 receptors by reparixin promoted neuroprotective effects by reducing the levels of neutrophil infiltration and tissue damage in the brain after cerebral occlusion and reperfusion in mice 7 . We also detected increased levels of pro-inflammatory cytokines TNF-α and IL-1β, which can contribute to the expansion of brain damage and death of neurons 18 .…”

Reparixin, a CXCR1/2 inhibitor in islet allotransplantation

“…12 However, similar to their study, and another following cytokine production after minor surgery, IL-1b levels remained unchanged; whereas, others observed a reduction in IL-1b levels in a cerebral ischemia reperfusion model following reparixin treatment. 12,20 There was a significant decrease in IL-6 production upon treatment when comparing serum levels at 24 h to those collected at 7 d after transplant which is promising since the cytokine is an important component in the response to inflammation and has been found to be increased after surgical trauma or injury. 21 Interestingly, 7 d after transplant, IL-12p70 cytokine production was significantly increased in the CTLA-4 Ig and reparixin treatment group compared to the group administered CTLA-4 Ig alone.…”

Cerebral ischemic damage in diabetes: an inflammatory perspective

“…A pharmacological inhibitor of C-X-C motif chemokine ligand-8 (CXCL-8), repertaxin, is neuroprotective in a rodent model of transient brain ischemia and its beneficial effects have been attributed to the inhibition of neutrophil recruitment and decreased secondary injury [146]. Inhibition of C-X-C motif chemokine receptor-1 (CXCR-1)/-2 receptors by reparixin (acting as a noncompetitive allosteric antagonist of the CXCR-1 and CXCR-2 receptors) protected the brain after MCAO [150]. After 24 h of reperfusion, pretreatment with reparixin significantly reduced myeloperoxidase (MPO) activity and reduced the levels of IL-1β [150].…”