A lipoxin A4 analog ameliorates blood-brain barrier dysfunction and reduces MMP-9 expression in a rat model of focal cerebral ischemia-reperfusion injury.

LXA(4) methyl ester (LXA(4)ME), a lipoxin A(4) analog, reduces ischemic insult in the rat models of transient or permanent cerebral ischemic injury. We investigated whether LXA(4)ME could ameliorate blood-brain barrier (BBB) dysfunction after stroke by reducing matrix metalloproteinase (MMP)-9 expression. Adult male rats were subjected to 2-h middle cerebral artery occlusion (MCAO) followed by 24-h reperfusion. Brain infarctions were detected by triphenyltetrazolium chloride (TTC) staining. BBB dysfunction was determined by examining brain edema and Evans Blue extravasation. Temporal expression of MMP-9 was determined by zymography and Western blot. The presence of tissue inhibitors of metalloproteinase-1 (TIMP-1) was also determined by Western blot in tissue protein sample. Brain edema and Evans Blue leakage were significantly reduced after stroke in the LXA(4)ME group and were associated with reduced brain infarct volumes. MMP-9 activity and expression were inhibited by LXA(4)ME after stroke. In addition, LXA(4)ME significantly increased TIMP-1 protein levels. Our results indicate that LXA(4)ME reduces brain injury by improving BBB function in a rat model of MCAO, and that a relationship exists between BBB permeability and MMP-9 expression following ischemic insult. Furthermore, these results suggest that LXA(4)ME-mediated reduction of MMP-9 following stroke are attributed to increased TIMP-1 expression.

Neuroprotective effect of lipoxin A4 methyl ester in a rat model of permanent focal cerebral ischemia.

Neuroprotective effect of lipoxin A(4) methyl ester (LXA(4) ME) was tested in a rat model of permanent middle cerebral artery occlusion. LXA(4) ME was administrated through intracerebroventricular injection immediately after middle cerebral artery was occluded. Administration of LXA(4) ME ameliorated neurological deficit, reduced infarct volume, attenuated histological damage, and decreased number of apoptotic neuron induced by ischemic insult. These neuroprotective effects of LXA(4) ME were associated with inhibition of neutrophil infiltration, lipid peroxidation, and astrocyte activation. In addition, LXA(4) ME also attenuated proinflammatory cytokines (TNF-alpha and IL-1beta) production. These data suggest that LXA(4) ME protects neuron against permanent cerebral ischemia by inhibiting inflammatory responses.

Lipoxin A4 analogue protects brain and reduces inflammation in a rat model of focal cerebral ischemia reperfusion.

Inflammation, which is known to be detrimental to the neurological outcome during the acute phase after ischemia, provides a potential preventative or therapeutic approach for acute stroke. Lipoxins are endogenous lipoxygenase derived eicosanoids and evokes protective actions in a range of pathophysiologic processes. Here, we evaluated the efficacy of 5 (S), 6 (R)-lipoxin A(4) methyl ester (LXA(4) ME), a stable synthetic analogue of lipoxin A(4) in cerebral ischemia reperfusion injury in rats. Transient focal cerebral ischemia was induced by middle cerebral artery occlusion for 2h. Intracerebroventricular administration of LXA(4) ME immediately after onset of ischemia ameliorated neurological dysfunctions, reduced infarction volume and attenuated neuronal apoptosis. Moreover, Treatment with LXA(4) ME suppressed neutrophils infiltration and lipid peroxidation levels; inhibited the activation of microglia and astrocytes; reduced the expression of pro-inflammatory cytokines TNF-alpha and IL-1beta; and up-regulated the expression of anti-inflammatory cytokines IL-10 and TGF-beta1 in the ischemic brain. In addition, activation of NF-kappaBeta was inhibited by LXA(4) ME treatment. These results demonstrate that treatment of LXA(4) ME affords strong neuroprotective effect against cerebral ischemia reperfusion injury, and that these effects might be associated with its anti-inflammatory property.