naphthoquinones and Stroke

Inflammatory damage plays an important role in cerebral ischemic pathogenesis and represents a new target for treatment of stroke. Shikonin has gained attention for its prominent anti-inflammatory property, but up to now little is known about shikonin treatment in acute ischemic stroke. The aim of this study was to evaluate the potential neuroprotective role of shikonin in cerebral ischemic injury, and investigate whether shikonin modulated inflammatory responses after stroke. Focal cerebral ischemia in male ICR mice was induced by transient middle cerebral artery occlusion. Shikonin (10 and 25 mg/kg) was administered by gavage once a day for 3 days before surgery and another dosage after operation. Neurological deficit, infarct volume, brain edema, blood-brain barrier (BBB) dysfunction, and inflammatory mediators were evaluated at 24 and 72 h after stroke. Compared with vehicle group, 25 mg/kg shikonin significantly improved neurological deficit, decreased infarct volume and edema both at 24 and 72 h after transient ischemic stroke, our data also showed that shikonin inhibited the pro-inflammatory mediators, including TLR4, TNF-α, NF-κB, and phosphorylation of p38MAPK in ischemic cortex. In addition, shikonin effectively alleviated brain leakage of Evans blue, up-regulated claudin-5 expression, and inhibited the over-expressed MMP-9 in ischemic brain. These results suggested that shikonin effectively protected brain against ischemic damage by regulating inflammatory responses and ameliorating BBB permeability.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Blood-Brain Barrier; Brain Ischemia; Claudin-5; Down-Regulation; Infarction, Middle Cerebral Artery; Male; Matrix Metalloproteinase 9; Mice; Mice, Inbred ICR; Naphthoquinones; Neuroprotective Agents; NF-kappa B; p38 Mitogen-Activated Protein Kinases; Stroke; Toll-Like Receptor 4; Tumor Necrosis Factor-alpha; Up-Regulation

2-Methoxystypandrone (2-MS), a naphthoquinone, has been shown to display an immunomodulatory effect in a cellular model. To explore whether 2-MS could protect mice against cerebral ischemic/reperfusion (I/R)-induced brain injury, we evaluated 2-MS's protective effects on an acute ischemic stroke by inducing a middle cerebral artery occlusion/reperfusion (MCAO) injury in murine model. Treatment of mice that have undergone I/R injury with 2-MS (10-100 μg/kg, i.v.) at 2 h after MCAO enhanced survival rate and ameliorated neurological deficits, brain infarction, neural dysfunction and massive oxidative stress, due to an enormous production of free radicals and breakdown of blood-brain barrier (BBB) by I/R injury; this primarily occurred with extensive infiltration of CD11b-positive inflammatory cells and upexpression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 and p65 nuclear factor-kappa B (NF-κB). All of these pathological changes were diminished by 2-MS; 2-MS also intensively limited cortical infarction and promoted upexpression of neurodevelopmental genes near peri-infarct cortex and endogenous neurogenesis near subgranular zone of hippocampal dentate gyrus and the subventricular zone, most possibly by inactivation of GSK3β which in turn upregulating β-catenin, Bcl-2 adam11 and adamts20. We conclude that 2-MS blocks inflammatory responses by impairing NF-κB signaling to limit the inflammation and oxidative stress for preservation of BBB integrity; 2-MS also concomitantly promotes neurodevelopmental protein expression and endogenous neurogenesis through inactivation of GSK3β to enhance β-catenin signaling for upexpression of neuroprotective genes and proteins.

Topics: Animals; Blood-Brain Barrier; Brain; Brain Ischemia; CD11b Antigen; Cyclooxygenase 2; Doublecortin Protein; Gene Expression Regulation; Immunologic Factors; Leukocytes; Male; Mice; Mice, Inbred ICR; Molecular Structure; Naphthoquinones; Neurogenesis; Nitric Oxide Synthase Type II; Reperfusion Injury; Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction; Stroke; Transcription Factor RelA