n-hydroxy-n--(4-butyl-2-methylphenyl)formamidine and Reperfusion-Injury

Cerebral ischemia-reperfusion injury is a common complication that occurs during stroke treatment. Increasingly, microRNAs have been found to participate in the modulation of neuron function; however, the role of microRNAs in cerebral ischemia-reperfusion injury remains unclear. We developed a mechanism of cerebral ischemia-reperfusion injury using a cellular model of oxygen-glucose deprivation and reoxygenation-induced injury in human neuroblastoma SH-SY5Y cells. We found that treatment of oxygen-glucose deprivation and reoxygenation promoted the apoptosis of SH-SY5Y cells. Analysis of microRNAs sequencing revealed that the expression of microRNA-27a-5p was induced, and microRNA-29b-3p expression was inhibited in neuroblastoma cells exposed to oxygen-glucose deprivation and reoxygenation. Either inhibition of microRNA-27a-5p or overexpression of microRNA-29b-3p mitigated oxygen-glucose deprivation and reoxygenation-induced cellular apoptosis. Bach1 was authenticated as a target gene of microRNA-27a-5p. Also, microRNA-27a-5p mediated the expression of Bach 1 along with its downstream signaling. N-hydroxy-N'-(4-butyl-2-methylphenyl)-formamidine protected against oxygen-glucose deprivation and reoxygenation-induced apoptosis while decreasing miR-27a-5p expression and increasing microRNA-29b-3p expression. These results suggested that microRNA-27a-5p and microRNA-29b-3p may contribute to oxygen-glucose deprivation and reoxygenation-induced cellular injury. At the same time, N-hydroxy-N'-(4-butyl-2-methylphenyl)-formamidine protects SH-SY5Y cells against oxygen-glucose deprivation and reoxygenation-induced injury partly through the inhibition of microRNA-27-a-5p and promotion of the Bach1/HO-1 signaling pathway.

Topics: Amidines; Apoptosis; Basic-Leucine Zipper Transcription Factors; Cell Line, Tumor; Glucose; Humans; Hypoxia; MicroRNAs; Reperfusion Injury

The arachidonic acid pathway metabolite 20-hydroxyeicosatetraenoic acid (20-HETE) contributes to ischemia/reperfusion brain injury. Inhibition of 20-HETE formation can protect the developing brain from global ischemia. Here, we examined whether treatment with the 20-HETE synthesis inhibitor N-hydroxy-N-4-butyl-2-methylphenylformamidine (HET0016) can protect the immature brain from traumatic brain injury (TBI). Male rats at postnatal day 9-10 underwent controlled cortical impact followed by intraperitoneal injection with vehicle or HET0016 (1 mg/kg, 5 min and 3 h post-injury). HET0016 decreased the lesion volume by over 50% at 3 days of recovery, and this effect persisted at 30 days as the brain matured. HET0016 decreased peri-lesion gene expression of proinflammatory cytokines (tumor necrosis factor-α [TNF-α], interleukin-1β [IL-1β]) at 1 day and increased reparative cytokine (IL-4, IL-10) expression at 3 days. It also partially preserved microglial ramified processes, consistent with less activation. HET0016 decreased contralateral hindlimb foot faults and improved outcome on the novel object recognition memory task 30 days after TBI. In cultured BV2 microglia, HET0016 attenuated the lipopolysaccharide-evoked increase in release of TNF-α. Our data show that HET0016 improves acute and long-term histologic and functional outcomes, in association with an attenuated neuroinflammatory response after contusion of an immature rat brain.

Topics: Amidines; Animals; Brain; Brain Injuries, Traumatic; Cytokines; Disease Models, Animal; Hydroxyeicosatetraenoic Acids; Inflammation; Male; Rats, Sprague-Dawley; Reperfusion Injury

What is the central question of this study? Is there a beneficial effect and what are the mechanisms of acute and multiple hyperbaric oxygenation (HBO

Topics: Amidines; Animals; Aryl Hydrocarbon Hydroxylases; Brain; Combined Modality Therapy; Cytochrome P-450 Enzyme System; Cytochrome P450 Family 2; Cytochrome P450 Family 4; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 1; Epoxide Hydrolases; Female; Gene Expression Regulation, Enzymologic; Hydroxyeicosatetraenoic Acids; Hyperbaric Oxygenation; Infarction, Middle Cerebral Artery; Neuroprotective Agents; Nitric Oxide Synthase Type III; Rats, Sprague-Dawley; Reperfusion Injury; RNA, Messenger; Steroid 16-alpha-Hydroxylase; Time Factors

N-hydroxy-N-(4-butyl-2-methylphenyl) formamidine (HET0016) is a specific 20-hydroxyeicosatetraenoic acid (20-HETE) inhibitor which was first synthesized in 2001. It has been demonstrated that HET0016 reduces cerebral infarction volume in rat middle cerebral artery occlusion (MCAO) models. However, little is known about the role of HET0016 in the blood-brain barrier (BBB) dysfunction after cerebral ischemia/reperfusion (I/R) injury. The present study was designed to examine the effect of HET0016 in a MCAO and reperfusion rat model to determine whether it protects against brain edema and BBB disruption. Rats were subjected to 90 min MCAO, followed by 4, 24, 48, and 72 h reperfusion. Brain edema was measured according to the wet and dry weight method. BBB permeability based on the extravasation of Evans blue and sodium fluorescein was detected. BBB ultrastructure alterations were presented through transmission electron microscope. Superoxide production in ischemic tissue was also measured by dihydroethidium fluorescent probe. Western blot was used to analyze the expression of Claudin-5, ZO-1, MMP-9, and JNK pathway. At 24h after reperfusion, HET0016 reduced brain edema and BBB leakage. Ultrastructural damage of BBB and the increase of superoxide production were attenuated by HET0016 treatment. Western blot showed that HET0016 suppressed the activation of MMP-9 and JNK pathway but restored the expression of Claudin-5 and ZO-1. In conclusion, these results suggest that HET0016 protects BBB dysfunction after I/R by regulating the expression of MMP-9 and tight junction proteins. Furthermore, inhibition of oxidative stress and JNK pathway may be involved in this protecting effect.

Topics: Amidines; Animals; Blood-Brain Barrier; Brain Edema; Brain Ischemia; Claudin-5; Male; MAP Kinase Signaling System; Matrix Metalloproteinase 9; Neuroprotective Agents; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Zonula Occludens-1 Protein

1 This study examined the contribution of cytochrome P450 metabolites of arachidonic acid in mediating ischaemia/reperfusion (I/R)-induced cardiac dysfunction in normal and diabetic rats. 2 We first compared the metabolism of arachidonic acid in microsomes prepared from the hearts of control rats and rats treated with streptozotocin (55 mg kg(-1)) to induce diabetes. The production of dihydroxyeicosatrienoic acids and epoxyeicosatrienoic acids (EETs) were similar in microsomes prepared from the hearts of control and diabetic rats, but the production of 20-hydroxyeicosatetraenoic acid (20-HETE) was two-fold higher in diabetic hearts than in control animals. 3 We then compared the change in left ventricular pressure (P(max)), left ventricular end-diastolic pressure, coronary flow and coronary vascular resistance in isolated perfused hearts obtained from control and diabetic animals after 40 min of global ischaemia (I) followed by 30 min of reperfusion (R). The decline in cardiac function was three- to five-fold greater in the hearts obtained from diabetic vs. control animals. 4 Pretreatment of the hearts with N-hydroxy-N'-(4-butyl-2-methyl-phenyl)-formamidine (HET0016, 1 microm), a selective inhibitor of the synthesis of 20-HETE, for 30 min before I/R resulted in significant improvement in the recovery of cardiac function in the hearts obtained from diabetic but not in control rats. Perfusion with an inhibitor of soluble epoxide hydrolase, 1-cyclohexyl-3-dodecyl urea (CDU), before I/R improved the recovery of cardiac function in hearts obtained from both control and diabetic animals. Perfusion with both HET0016 and CDU resulted in significantly better recovery of cardiac function of diabetic hearts following I/R than that seen using either drug alone. Pretreatment of the hearts with glibenclamide (1 microm), an inhibitor of ATP-sensitive potassium channels, attenuated the cardioprotective effects of both CDU and HET0016. 5 This is the first study to suggest that acute blockade of the formation of 20-HETE and/or reduced inactivation of EETs could be an important strategy to reduce cardiac dysfunction following I/R events in diabetes.

Topics: 8,11,14-Eicosatrienoic Acid; Amidines; Animals; Arachidonic Acid; Blood Glucose; Body Weight; Coronary Circulation; Cytochrome P-450 Enzyme System; Diabetes Mellitus, Experimental; Enzyme Inhibitors; Epoxide Hydrolases; Glyburide; Heart; Hydroxyeicosatetraenoic Acids; Male; Microsomes; Myocardium; Rats; Rats, Wistar; Reperfusion Injury; Urea; Vascular Resistance; Ventricular Dysfunction, Left

Cytochrome P450 metabolism of arachidonic acid produces the potent vasoconstrictive metabolite, 20-hydroxyeicosatetraenoic acid (20-HETE). Recent studies have implicated 20-HETE as a vasoconstrictive mediator in hemorrhagic stroke. The purpose of this study was to determine the effect of the 20-HETE inhibitor, HET0016, on lesion volume and cerebral blood flow (CBF) after temporary middle cerebral artery occlusion (MCAO) in rats. Plasma pharmacokinetics and tissue concentrations of HET0016 were determined after a 10 mg/kg intraperitoneal dose. Separate rats were treated with HET0016 or vehicle before 90 mins of MCAO. Lesion volume was assessed by 2,3,5-triphenyl-tetrazolium-chloride and cerebral flow was determined using laser Doppler flow. The effect of MCAO on in vitro microsomal formation of mono-oxygenated arachidonic acid metabolites was also determined. Results show that HET0016 has a short biologic half-life, distributes into the brain, and is associated with a 79.6% reduction in 20-HETE concentration in the cortex. Lesion volume was greatly reduced in HET0016-treated (9.1%+/-4.9%) versus vehicle-treated (57.4%+/-9.8%; n=6; P<0.001) rats. An attenuation of the observed decrease in CBF was observed in HET0016-treated (180 mins 89.2%+/-6.2%; 240 mins 88.1%+/-5.7% of baseline flow) versus vehicle control (180 mins 57.6%+/-19.0%; 240 mins 53.8%+/-20.0% of baseline flow; n=6; P<0.05). Brain cortical microsomal formation rate of 20-HETE was also reduced at 24 h in the ipsilateral hemisphere after MCAO. These data support a significant role for 20-HETE in the pathogenesis of ischemic stroke.

Topics: Amidines; Animals; Brain Injuries; Brain Ischemia; Cerebrovascular Circulation; Cytochrome P-450 Enzyme System; Hydroxyeicosatetraenoic Acids; Male; Microsomes; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Stroke; Vasoconstriction