Effect of thymoquinone on hepatorenal dysfunction and alteration of CYP3A1 and spermidine/spermine N-1-acetyl-transferase gene expression induced by renal ischaemia-reperfusion in rats

Objectives Renal ischaemia–reperfusion (I/R) is a well‐characterised model of acute renal failure that causes both local and remote organ injury. The aim of this work was to investigate the effect of thymoquinone, the main constituent of the volatile oil extracted from Nigella sativa seeds, on renal and hepatic changes after renal ischaemia–reperfusion. Methods Male Sprague‐Dawley rats were divided into sham I/R vehicle‐treated groups, and I/R thymoquinone‐treated groups. Thymoquinone (10 mg/kg, p.o.) was administered for ten consecutive days to the I/R thymoquinone group before injury. I/R and I/R thymoquinone groups were subjected to 30‐min ischaemia followed by 4‐h reperfusion. Key findings I/R resulted in a significant increase in malondialdehyde (MDA) level and decreases in glutathione‐S‐transferase (GST) and superoxide dismutase (SOD) activity in liver and kidney tissues. Thymoquinone treatment caused the reversal of I/R‐induced changes in MDA as well as GST and SOD activity. Moreover, I/R caused a significant rise in creatinine and alanine aminotransferase serum levels. CYP3A1 mRNA expression was induced significantly by I/R in both liver and kidney tissues compared with sham group. Thymoquinone reduced significantly this increase. I/R caused induction of mRNA expression of spermidine/spermine N‐1‐acetyl‐transferase (SSAT), a catabolic enzyme that participates in polyamine metabolism, in liver and kidney tissues. Thymoquinone reduced SSAT mRNA expression significantly in liver and markedly in kidney. Conclusions These findings suggested that thymoquinone protected against renal I/R‐induced damage through an antioxidant mechanism as well as the decrease of CYP3A1 and SSAT gene expression.     

Effect of thymoquinone,a constituent of <Emphasis Type="Italic">Nigella sativa</Emphasis> L., on ischemia–reperfusion in rat skeletal muscle

Thymoquinone have been shown to decrease ischemia–reperfusion injury (IRI) in some tissues such as gastric mucosa and brain. In this study, the effect of thymoquinone was evaluated on an animal model of IRI in the rat hind limb. Hind limb ischemia was induced by clamping the common femoral artery and vein. After 2 h ischemia, the clamp on the femoral vessels was taken off and the animal underwent 1 h reperfusion. Muscle injuries were evaluated by recording the electromyographic (EMG) potentials and performing some biochemical analysis including thiobarbituric acid reactive substances (TBARS), total sulfhydryl (SH) groups, and antioxidant capacity of muscle using ferric reducing ability of plasma (FRAP) assay. Ischemia was induced using free-flap surgery in skeletal muscle. Thymoquinone (20, 40 and 80 mg/kg) and normal saline (10 ml/kg) were administered intraperitoneally 1 h prior to reperfusion. The average peak-to-peak amplitude during ischemic reperfusion was significantly increased in thymoquinone groups in comparison with the control group. Following thymoquinone administration, the total SH contents and antioxidant capacity were elevated in muscle flap. The malondialdehyde (MDA) level was declined significantly in test groups. It is concluded that thymoquinone have some protective effects against the muscle tissue injury caused by lower limb ischemia–reperfusion.     

Geraniol protects hippocampal CA1 neurons and improves functional outcomes in global model of stroke in rats

Geraniol (GE), an acyclic monoterpene, is a chief constituent of essential oils of herbs and fruits. It possesses diverse pharmacological actions like antioxidant, anti-inflammatory, anti-apoptotic, and anti-parkinson. However, its neuroprotective potential in stroke is yet to be explored at large. The present study evaluated the neuroprotective potential of GE against the global model of cerebral ischemia/reperfusion (I/R)-injury in rats. Bilateral common carotid artery (BCCA) occlusion for 30 min followed by 7 days of reperfusion caused varied biochemical/enzymatic alterations viz. increase in levels of lipid peroxidation (LPO), nitric oxide (NO), xanthine oxidase (XO), and decrease in the levels of cerebroprotectives like superoxide dismutase (SOD), catalase (CAT), total thiols, and glutathione (GSH). GE-pretreatment markedly reversed these changes and restored the levels of protective enzymatic and non-enzymatic antioxidants near to normal compared to I/R group. Besides, GE treatment showed marked improvement in anxiety-related behavior and neuronal deficits in animals subjected to I/R injury. Moreover, 2,3,5-triphenyl tetrazolium chloride (TTC)-stained rat brain coronal sections and histopathological studies revealed neuronal protection against I/R-injury, as evidenced by a reduction in infarct area (%) and an increase in hippocampal CA1 neuronal density in the GE-treated groups. The results of this study revealed that GE exhibited potential neuroprotective activity by reducing oxidative stress and infarction area, and protecting hippocampal CA1 neurons against I/R-injury in the global stroke model in rats.     

双苯氟嗪对大鼠全脑缺血再灌注损伤的保护作用

目的研究双苯氟嗪(D ip)对大鼠急性全脑缺血再灌注损伤的保护作用,并初步探讨其作用机制。方法采用Pu lsinelli等的四动脉结扎法(4-VO)造成大鼠全脑缺血再灌注损伤模型,观察大鼠全脑缺血再灌注损伤后早期脑组织水分的变化、生化指标的改变,再灌注后期行为学和组织形态学的改变。结果缺血30 m in再灌注1 h脑组织水分及丙二醛(MDA)含量升高,乳酸脱氢酶(LDH)和超氧化物歧化酶(SOD)活性下降;缺血20 m in再灌注5 d后海马CA1区椎体细胞层破裂,胞核固缩或溶解,间质也变得疏松。行为学实验表明大鼠记忆力明显受损。D ip可不同程度地抑制上述变化,能对抗自由基损伤和脑水肿,并能保护海马CA1区神经元免受缺血损伤,提高大鼠对空间辨别的记忆能力。结论D ip对大鼠全脑缺血再灌注早期损伤有明显的保护作用,并能保护海马CA1区神经元免受缺血损伤,提高大鼠对空间辨别的记忆能力,对迟发性神经元死亡有一定的保护作用。这可能与其抗脂质过氧化产物产生有关。     

Effects of amelioration of total flavonoids from stems and leaves of Scutellaria baicalensis Georgi on cognitive deficits, neuronal damage and free radicals disorder induced by cerebral ischemia in rats

Previous studies reported that the total flavonoids from the stems and leaves of Scutellaria baicalensis Georgi (TFSS) could enhance and improve learning and memory abilities in experimental animals, and reduce the neuronal pathologic alterations induced by some reagents in mice. The present study examined whether TFSS can improve memory dysfunction, neuronal damage, and abnormal free radicals induced by permanent cerebral ischemia in rats. The permanent cerebral ischemic model in rats was produced by bilateral ligation of the common carotid arteries. The influence of permanent cerebral ischemia on learning and memory was determined in the Morris water maze. The neuronal damage in the hippocampus and cerebral cortex was assessed by the neuronal morphologic observations. The contents of malondialdehyde (MDA) and nitric oxide (NO), and the activities of superoxide dismutase (SOD) and catalase (CAT) in the hippocampus and cerebral cortex were measured using thiobarbituric acid, nitrate reductase, xanthine-xanthine oxidase, and ammonium molybdate spectrophotometric methods, respectively. In learning and memory performance tests, cerebral ischemic rats always required a longer latency time to find the hidden platform and spent a shorter time in the target quadrant in the Morris water maze. TFSS 17.5-70 mg.kg(-1) daily orally administered to ischemic rats for 20 d, from day 16-35 after operation differently reduced the prolonged latency and increased swimming time spent in the target quadrant. In neuronal morphologic observations, daily oral TFSS 17.5-70 mg.kg(-1) for 21 d, from day 16-36 after operation markedly inhibited the ischemia-induced neuronal damage. In addition, the increased contents of MDA and NO, and SOD activity, and the decreased activity of CAT in the hippocampus and cerebral cortex induced by cerebral ischemia were differently reversed. The reference drug piracetam (140 mg.kg(-1) per day for 20-21 d) similarly improved impaired memory and neuronal damage but had no significant effects on free radicals in ligated rats. TFSS can improve memory deficits and neuronal damage in rats after permanent cerebral ischemia, which may be beneficial in the treatment of cerebrovascular dementia.     

Neuroprotective effect of MnTMPyP, a superoxide dismutase/catalase mimetic in global cerebral ischemia is mediated through reduction of oxidative stress and DNA fragmentation

Excessive generation of free radicals and decreased levels of the antioxidant enzymes such as superoxide dismutase (SOD) and catalase have been observed after brain ischemic reperfusion injury. In the present study, we have investigated the neuroprotective potential of MnTMPyP (Mn(III)tetrakis(1-methyl-4-pyridyl)porphyrin pentachloride), a SOD/Catalase mimetic in bilateral carotid artery occlusion model of global cerebral ischemia in Mongolian gerbils. Five minutes of bilateral carotid artery occlusion produced global cerebral ischemia, which was evident from the neurological deficits, spontaneous motor activity and the decrease in the number of viable hippocampal CA1 neurons. Global ischemia was also associated with increased levels of malondialdehyde, decreased levels of SOD and catalase, and increased TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling) positive cells, indicating oxidative stress and DNA fragmentation. Administration of a single dose of MnTMPyP, 1 mg/kg i.p. (30 min before occlusion), produced no significant neuroprotection; however, 3 mg/kg i.p. (30 min before to occlusion) produced significant reduction in neurological score, spontaneous motor activity and CA1 pyramidal neuronal damage. MnTMPyP also attenuated the increased levels of malondialdehyde and improved the levels of SOD and catalase, and inhibited DNA fragmentation in the ischemic animals. Multiple administration of MnTMPyP, 3 mg/kg i.p. (three times: 30 min before, 1 h and 3 h after occlusion), produced better neuroprotection as compared to single dose administration. This study demonstrates that the neuroprotective effect of MnTMPyP in global ischemia is mediated through reduction in oxidative stress and DNA fragmentation.     

Protective effect of vinconate on ischemia-induced neuronal damage in the rat hippocampus.

The protective effect of vinconate, a vinca alkaloid derivative, on ischemia-induced neuronal damage was investigated using a model of rat forebrain ischemia caused by occlusion of four vessels. Hippocampal cell loss was observed histologically and neurochemically 5 days after 10 min of ischemia. Treatment with vinconate (50 and 200 mg/kg i.p.) before cerebral ischemia significantly suppressed neuronal cell loss in the hippocampal CA1 region and the decrease in the content of neuroactive amino acids in the hippocampus. The release of neuroactive amino acids in the hippocampus was significantly increased by cerebral ischemia. Pretreatment with vinconate (50 and 200 mg/kg i.p.) significantly attenuated the increased release of glutamic acid and aspartic acid, but not the release of gamma-aminobutyric acid (GABA), taurine and glycine. This suppressive effect of vinconate was antagonized by scopolamine (10(-5) M). The addition of vinconate (10(-11)-10(-4) M) had no effect on the binding of [3H]MK-801. These results indicate that pretreatment with vinconate attenuates the ischemia-induced release of excitatory amino acids into the extracellular space of the hippocampus via the stimulation of presynaptic muscarinic acetylcholine receptors. The present results also suggest that this suppressive effect of vinconate on the release of excitatory amino acids (glutamic acid and aspartic acid) may play a crucial role in the protective action of this agent against ischemia-induced neuronal damage in the hippocampus.     

硫化氢预处理对兔脊髓缺血再灌注神经损伤的保护作用及其机制研究

目的 观察硫化氢（H2S）预处理对兔脊髓缺血再灌注损伤的保护效应。方法 将雄性新西兰大白兔随机分为假手术组、缺血再灌注组和H2S预处理组,观察H2S对模型神经行为学的影响,以及对神经细胞凋亡和超氧化物歧化酶（SOD）、过氧化氢酶（CAT）的影响。结果 H2S预处理提高神经功能的评分,降低神经细胞的凋亡,增强SOD和CAT活性（P＜0.05）。结论 H2S对脊髓缺血再灌注损伤有较好的保护作用,其作用机制可能与抗自由基生成有关     

Tadalafil improves short-term memory by suppressing ischemia-induced apoptosis of hippocampal neuronal cells in gerbils

Cerebral ischemia resulting from transient or permanent cerebral artery occlusion leads to neuronal cell death, and eventually causes neurological impairments. Tadalafil (Cialis^®) is a long-acting phosphodiesterase type-5 (PDE-5) inhibitor used to treat erectile dysfunction. The therapeutic effects of PDE-5 inhibitors on chronic obstructive pulmonary disease, prostate hyperplasia, hypertension, and coronary heart disease have been reported. The present study investigated the effects of tadalafil on short-term memory, cyclic guanosine monophosphate (cGMP) level, apoptotic neuronal cell death, and cell proliferation in the hippocampus following transient global ischemia in gerbils. For this study, a step-down avoidance task, cGMP assay, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay, and immunohistochemistry for caspase-3 and 5-bromo-2′-deoxyuridine were performed. The results revealed that ischemic injury increased apoptotic neuronal cell death in the hippocampal CA1 region, impaired short-term memory, and decreased cGMP level. Ischemic injury enhanced cell proliferation in the hippocampal dentate gyrus. Tadalafil treatment improved short-term memory by suppressing ischemia-induced apoptotic neuronal cell death in the hippocampal CA1 region, and decreased cGMP level. Also, tadalafil suppressed the ischemia-induced increase in cell proliferation in the hippocampal dentate gyrus. We showed that tadalafil can overcome ischemia-induced apoptotic neuronal cell death, thus facilitates recovery following ischemic cerebral injury.     

褪黑素对大鼠全脑缺血-再灌注损伤及P53蛋白表达的影响

探讨了褪黑素 (MT)神经保护作用的机理 .采用大鼠“四动脉结扎法”制成全脑缺血 (2 0min) 再灌注模型 .①于再灌注开始时ipMT 2 .5或 10mg·kg- 1,于再灌注 1h断头取脑 ,检测谷胱甘肽过氧化物酶 (GSH Px) ,超氧化物歧化酶 (SOD)的活性以及丙二醛 (MDA)的含量 ;②于再灌注后 0 ,1,2 ,6h重复ipMT 2 .5或 10mg·kg- 1共 4次 ,再灌后 2 4h取脑组织 ,应用免疫组化方法检测海马CA1区神经细胞内P5 3蛋白的表达 .结果可见 ,MT两个剂量均可提高大鼠全脑缺血 再灌注后脑组织中GSH Px及SOD的活性 ,降低MDA含量 ,均可抑制海马CA1区损伤蛋白P5 3的表达 .结果表明 ,MT对缺血 再灌注后脑损伤的保护作用至少与以下两方面有关 :①增强抗氧化酶GSH Px ,SOD的活性 ,减少脂质过氧化损伤 ;②抑制缺血 再灌后P5 3蛋白的表达     

土党参多糖对小鼠脑缺血/再灌注损伤的保护作用

目的探讨土党参多糖对小鼠脑缺血/再灌注损伤的保护作用。方法将KM小鼠随机分为7组,假手术组、模型组、舒血宁组(100 mg.kg-1)、尼莫地平组(100 mg.kg-1)及土党参多糖高、中、低剂量组(300、150、75 mg.kg-1)。采用反复缺血/再灌注法造模,观察小鼠海马区神经元形态,测定小鼠脑组织中丙二醛(MDA)、一氧化氮(NO)、乙酰胆碱(ACh)、葡萄糖含量,超氧化物歧化酶(SOD)、谷胱甘肽(GSH)、乙酰胆碱酯酶(AChE)和ATP酶活性。结果土党参多糖各剂量组可明显减轻小鼠海马区神经元损伤,降低脑组织中MDA和NO含量(P<0.05或P<0.01),而对SOD、GSH无明显影响;多糖中剂量组能明显提高ACh含量(P<0.01),而低、高剂量组与模型组相比差异无显著性;中、高剂量组能明显降低AChE活性,提高ATP酶、糖代谢活性(P<0.05或P<0.01)。结论土党参多糖对小鼠脑缺血/再灌注损伤具有保护作用,可能与其神经营养、抗氧化、代谢调控、降低乙酰胆碱酯酶活性有关。     

Protective effects of extract of Coeloglossum viride var. bracteatum on ischemia-induced neuronal death and cognitive impairment in rats

Our earlier study demonstrated that Coeloglossum viride (L.) Hartm. var. bracteatum (Willd.) extract (CE) significantly improved the impaired memory in mice caused by permanent two-vessel occlusion. To investigate whether chronic treatment with CE could influence cerebral ischemia-induced neuronal and cognitive impairments, we examined the effects of CE on two different kinds of cerebral injury: transient middle cerebral artery occlusion model of focal cerebral ischemia; four-vessel occlusion model of transient global forebrain ischemia. CE treatment (5 mg/kg, orally) significantly reduced lesion volume, and improved the performance of passive avoidance and rotarod motor tasks in transient middle cerebral artery occlusion rats. In the four-vessel occlusion model, neuronal cell loss in CA1 of hippocampus was significantly decreased and the performance in the Morris water maze was significantly improved in rats administered CE. We conclude that treatment with CE attenuated learning and memory deficits, motor functional disability, and neuronal cell loss induced by global or focal cerebral ischemia. These results suggest that CE may be a potential candidate for the treatment of vascular dementia.     

Possible mechanism of action in melatonin attenuation of haloperidol-induced orofacial dyskinesia

Tardive dyskinesia (TD) is a late complication of prolonged neuroleptic treatment characterized by involuntary movements of the oral region. In spite of high incidence and much research, the pathophysiology of this devastating movement disorder remains elusive. Chronic treatment with neuroleptics leads to the development of abnormal oral movements in rats, referred to as vacuous chewing movements (VCMs). VCMs in rats are widely accepted as an animal model of TD. Rats chronically treated with haloperidol (1.5 mg/kg ip) significantly developed VCMs and tongue protrusions. Melatonin dose-dependently (1, 2, and 5 mg/kg) reversed the haloperidol-induced VCM and tongue protrusions frequencies. Biochemical analysis reveals that chronic haloperidol treatment significantly induced lipid peroxidation and decreased the forebrain glutathione (GSH) levels in the rats. Chronic haloperidol-treated rats also showed decreased levels of antioxidant defense enzymes, superoxide dismutase (SOD), and catalase. Coadministration of melatonin (1, 2, and 5 mg/kg) along with haloperidol significantly reduced the lipid peroxidation and restored the decreased GSH levels by chronic haloperidol treatment, and significantly reversed the haloperidol-induced decrease in forebrain SOD and catalase levels in rats. However, a lower dose of melatonin (1 mg/kg) failed to reverse chronic haloperidol-induced decreases in forebrain GSH, SOD, and catalase levels. In conclusion, melatonin could be screened as a potential drug candidate for the prevention or treatment of neuroleptic-induced orofacial dyskinesia.     

Caffeic acid phenethyl ester (CAPE) protects rat skeletal muscle against ischemia-reperfusion-induced oxidative stress

Oxygen-derived free radicals have been implicated in the pathogenesis of skeletal muscle injury after ischemia-reperfusion. Caffeic acid phenethyl ester, an active component of propolis extract, exhibits antioxidant properties. The aim of this study was to assess the effects of caffeic acid phenethyl ester (CAPE) and alpha-tocopherol (vit E) on ischemia/reperfusion (I/R) injury in a rat hind limb ischemia/reperfusion model. For this purpose, ischemia was induced in anesthetized rats by unilateral (right) femoral artery clipping for 2 h followed by 2 h of reperfusion. Four groups were studied: sham, I/R, I/R+CAPE and I/R+vit E. Drugs were administered intraperitoneally after 1 h of ischemia and I/R rats received saline vehicle. After 2 h of reperfusion, venous blood was sampled and the right gastrocnemius muscle was harvested. Plasma and tissue were assayed for malondialdehyde (MDA), superoxide dismutase (SOD) and nitric oxide (NO) metabolites. Tissue was also assayed for catalase (CAT) activity. Both tissue and plasma NO levels, MDA levels, SOD activities was significantly increased in I/R groups compared to control groups. The two treated groups showed decreased MDA and NO in both muscle and plasma compared to the I/R group. No differences were noted in muscle tissue SOD in three I/R groups, but SOD activity were increased in the plasma of I/R+CAPE and I/R+vit E groups compared with I/R group. Whereas tissue CAT activity was not changed among groups. Our results indicate that CAPE has antioxidant properties similar to those of vit E in this model and may attenuate the harmful effects of hind limb I/R in skeletal muscle.     

Effect of MAO-B inhibition against ischemia-induced oxidative stress in the rat brain. Comparison with a rational antioxidant

An increasing number of reports suggest the involvement of oxidative stress in neurodegenerative diseases where the increased formation of reactive oxygen species (ROS) leads to neuronal damage and cell death. Dopamine may contribute to neurodegenerative disorders such as Parkinson's disease and ischemia/reperfusion-induced damage. Monoamine oxidase (MAO) enzyme (particularly MAO-B) is responsible for metabolizing dopamine and plays an important role in oxidative stress through altering the redox state of neuronal and glial cells. MAO participates in the generation of hydroxyl radicals during ischemia/reperfusion. This suggests the possible use of MAO inhibitors as neuroprotective agents for treating ischemic injury. The protective effect of deprenyl (N-methyl-N-(1-methyl-2-phenyl-ethyl)-prop-2-yn-1-amine, CAS 14611-51-9) (2 and 10 mg/kg), a MAO-B inhibitor, and beta-carotene (10 and 20 mg/kg), a natural antioxidant, was examined in a rat model of cerebral ischemia. Ischemia was induced in rats by bilateral carotid artery occlusion for 1 h followed by declamping for another hour. The effect of the drugs on the brain activity of lactate dehydrogenase (LDH) and some of the oxidative stress biomarkers such as brain activity of superoxide dismutase (SOD) and catalase (CAT) enzymes and brain malondialdehyde (MDA) content was determined. In addition, the content of catecholamines such as noradrenaline (NA) and dopamine (DA) was determined. Deprenyl decreased the ischemia-induced elevation of LDH activity and MDA content and normalized the SOD activity. In addition, deprenyl increased the CAT activity back to normal, and increased the noradrenaline and dopamine content in the brain of rats. Beta-carotene administration ameliorated the effect of ischemia followed by reperfusion (I/R) demonstrated as decreasing the LDH activity and MDA content and by increasing the SOD activity. The drug also increased CAT activity in the brain of rats. However, beta-carotene did not alter the NA and DA content. These results indicate that deprenyl protected the rat brains against the ischemia-induced oxidative damage, an effect which might be explained through multiple mechanisms, possibly due to reduction of dopamine catabolism with a subsequent increased activity on dopaminergic D2 receptors and suppressing the action of ROS as well.     

糖尿病大鼠肾脏抗氧化防御系统机能的改变

目的：探讨糖尿病对肾脏抗氧化防御机能的影响。方法：观察12周糖尿病大鼠肾皮质丙二醛(MDA)及谷胱甘肽(GSH)水平,以及超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-PX)、谷胱甘肽S转移酶(GSH-ST)和过氧化氢酶(CAT)活性的变化。结果：糖尿病大鼠肾组织中SOD、CAT活性下降;GSH含量显著降低;MDA没有变化;GSH-PX活性却明显增强。结论：糖尿病大鼠肾组织抗氧化防御机能明显下降。     

大蒜新素对脑缺血再灌注大鼠海马的保护作用

目的探讨大蒜新素对脑缺血再灌注海马组织的保护作用与钙转运的关系。方法采用4血管闭塞法制备大鼠全脑缺血再灌注模型,大蒜新素10,20和30mg.kg-1分2次于缺血前30min和再灌注后10min经尾静脉注入,每次注射总量的1/2。再灌注后24h取大鼠海马,甲苯胺蓝染色显微镜下观察海马组织学改变及存活神经元密度;定磷比色法测定Ca2+-转运ATP酶活性;原子吸收法测定钙含量。结果全脑缺血10min再灌注24h时,海马CA1区形态学改变明显,神经元密度明显降低;海马组织Ca2+-转运ATP酶活性降低;组织钙含量显著增加。静脉给予大蒜新素可使缺血再灌注海马组织形态学改变程度明显减轻,存活神经元密度增加,Ca2+-转运ATP酶活性增加,组织钙含量降低。结论大蒜新素对全脑缺血再灌注后海马组织具有明显的保护作用;增加Ca2+-转运ATP酶活性、减少组织钙含量可能是其保护作用的机制之一。     

Diallyl trisulfide (DATS) effectively attenuated oxidative stress-mediated liver injury and hepatic mitochondrial dysfunction in acute ethanol-exposed mice

The protective effects of diallyl trisulfide (DATS) on acute ethanol-induced liver injury were investigated. Mice were pretreated with DATS (30mg/kgbw) for 7d before being exposed to ethanol (4.8g/kgbw). The biochemical indices (aspartate amino transferase, AST; alanine amino transferase, ALT; triglyceride, TG) were examined to evaluate the protective effects. Mitochondria were isolated for the mitochondrial permeability transition (MPT), membrane potential (DeltaPsi(m)) and adenosine nucleotide pool assay. The lipid peroxidation (malondialdehyde, MDA), non-enzymatic antioxidant (glutathione, GSH) and enzymatic antioxidants (superoxide dismutase, SOD; catalase, CAT; glutathione reductase, GR; glutathione peroxidase, GSH-Px) were measured both in the liver homogenate and isolated mitochondria. Acute ethanol exposure resulted in the significant increase of the ALT, AST and TG levels and hepatic mitochondria dysfunction shown as MPT, and the decreases of DeltaPsi(m), ATP and energy charge (EC). However, DATS pretreatment dramatically attenuated these adverse effects. Beside this, DATS was found to significantly inhibit the increase of the hepatic and mitochondrial MDA levels, which were decreased by 33.3% (P<0.01) and 39.0% (P<0.01), respectively. In addition, DATS pretreatment markedly suppressed the ethanol-induced decrease of the hepatic GSH level and increased the mitochondrial GSH level. Moreover, the activities of the hepatic antioxidant enzymes (SOD, CAT, and GR) and the mitochondrial antioxidant enzymes (SOD, GR, and GSH-Px) were significantly boosted. Thus, we concluded that DATS dramatically attenuated acute ethanol-induced liver injury and mitochondrial dysfunction. The increase of the hepatic and mitochondrial GSH levels and the elevation of the antioxidant enzymes activities should account for the preventive effects.     

Protective effect of chronic ethyl docosahexaenoate administration on brain injury in ischemic gerbils

There is evidence that the excessive generation of reactive oxygen free radicals contributes to the brain injury associated with cerebral ischemia. In the present study, the protective effect of chronic administration of ethyl docosahexaenoate (E-DHA) against oxidative brain injury was evaluated in the gerbil model of transient cerebral ischemia. Weanling male gerbils were orally pretreated with either E-DHA (200 mg/kg) or vehicle, once a day, for 10 weeks and subjected to bilateral occlusion of common carotid arteries for 10 min. At the different reperfusion times, E-DHA pretreatment significantly inhibited the increases in the production of brain salicylate-derived 2,5-dihydroxybenzoic acid (2,5-DHBA) and content of brain malonildialdehyde (MDA). The superoxide dismutase (SOD) activity was not modified; however, pretreatment with E-DHA significantly prevented the level of brain-reduced glutathione (GSH) and activities of brain glutathione peroxidase (GSH-P(X)) and catalase (CAT) from declines caused by cerebral ischemia. Moreover, ischemia and reperfusion-induced delayed neuronal loss in the hippocampus CA1 sector and locomotor hyperactivity were also significantly attenuated by pretreatment with E-DHA. These results suggested that the neuroprotective effect of E-DHA might be due to its antioxidant property.     

A DOPA antagonist, DOPA cyclohexyl ester inhibits transient brain ischemia-induced release of glutamate and delayed neuronal cell death in striatal and hippocampal region of in vivo rats

We have previously obtained evidence that DOPA is probably involved in an upstream process of mechanisms for in vivo neuronal cell death in striatum. We attempted to clarify whether or not this is also the case in hippocampal region of conscious Wistar rats. Four vessels were occluded for 5 min during microdialysis of hippocampus. DOPA, dopamine and glutamate (Glu) in perfusates collected every 10 min were measured by HPLC-ECD and spectrophotometer. Delayed neuronal cell death in hippocampus was evaluated 96 hr after ischemia. Five-min transient brain ischemia induced Glu release, with the peak being 2.5-fold of a basal release at the fraction immediately after ischemia. The release of DOPA and dopamine was not consistently detectable, but an increase was sometimes observed during and after ischemia. Delayed neuronal cell death was slight to moderate with 5-min ischemia. Intrastriatal perfusion of DOPA cyclohexyl ester (DOPA CHE) at 100 nM, a novel stable potent competitive DOPA antagonist, almost completely inhibited the ischemia-induced glutamate release, and protected hippocampal neurons from delayed cell death. Endogenously released DOPA itself seems to act on its recognition site and to behave as a causal and/or deteriorating factor on glutamate release and resultant delayed neuronal cell death by transient ischemia in rats.