The effect of moderate hypothermia in acute ischemic stroke on pericyte migration: An ultrastructural study

Pericytes are essential components of the blood–brain barrier together with endothelial cells and astrocytes. Any disturbance of brain perfusion may result in blood–brain barrier dysfunction due to pericyte migration from the microvascular wall. The neuroprotective influence of hypothermia on ischemic brain injury has been clearly shown in models of both global and focal ischemia. Leakage of plasma proteins contributes to the extension of neuronal injury and hypothermia has a neuroprotective influence during the ischemic insult. This line of thinking impelled us to investigate the possible role of the pericytes in the occurrence of hypothermic protection during cerebral ischemia.In this study, we examined at the ultrastructural level the effect of moderate hypothermia on microvascular pericyte responses using a rat model of permanent middle cerebral artery occlusion. Twenty rats were divided into four groups. Middle cerebral artery occlusion was performed in all rats except the control group (first group), which was used to determine the pericyte morphology under normal conditions. In the second group, pericyte response to irreversible ischemia under normothermic conditions was examined at the end of the first hour. In the third group, pericyte response to hypoxia was examined under normothermic conditions three hours after ischemia. In the fourth group, temporalis muscle temperature was maintained at 27–29 °C for 1 h after middle cerebral artery occlusion and pericyte response was then examined at the ultrastructural level. In ischemic normothermic conditions at the end of the first hour (Group 2), a separation was observed between pericytes and the basement membrane and this was interpreted as pericyte migration from the microvascular wall. In ischemic normothermic conditions at the end of the third hour (Group 3), basement membrane disorganization and increased space between the basement membranes were seen in addition to the differentiation of second group. In ischemic hypothermic conditions at the end of the first hour (Group 4), pericyte separation or migration from basement membrane were not seen and the blood–brain barrier remained firm. These findings were interpreted by the authors as a possible relationship between pericyte behavior and neural protection during hypothermia. We suggest that hypothermia may delay the pericyte response but not necessarily attenuate it, and should be associated with hypothermic protection.     

Dragon's blood dropping pills have protective effects on focal cerebral ischemia rats model

Dragon's blood is a bright red resin obtained from Dracaena cochinchinensis (Lour.) S.C.Chen (Yunnan, China). As a traditional Chinese medicinal herb, it has great traditional medicinal value and is used for wound healing and to stop bleeding. Its main biological activity comes from phenolic compounds. In this study, phenolic compounds were made into dropping pills and their protective effects were examined by establishing focal cerebral ischemia rats model used method of Middle Cerebral Artery Occlusion (MCAO), and by investigating indexes of neurological scores, infarct volume, cerebral index, cerebral water content and oxidation stress. Compared to model group, high, middle and low groups of Dragon's blood dropping pills could improve the neurological function significantly (p < 0.01) and reduce cerebral infarct volume of focal cerebral ischemia rats remarkably (p < 0.05–0.01). Meanwhile, each group could alleviate cerebral water content and cerebral index (p < 0.05–0.01) and regulate oxidative stress of focal cerebral ischemia rats obviously (p < 0.05–0.01). Activities of middle group corresponded with that treated with positive control drug. The results obtained here showed that Dragon's blood dropping pills had protective effects on focal cerebral ischemia rats.     

Sesamin attenuates behavioral,biochemical and histological alterations induced by reversible middle cerebral artery occlusion in the rats

Restoration of blood flow to an ischemic brain region is associated with generation of reactive oxygen species (ROS) with consequent reperfusion injury. ROS cause lipid peroxidation, protein oxidation, and DNA damage, all of which are deleterious to cells. So diminishing the production of free radicals and scavenging them may be a successful therapeutic strategy for the protection of brain tissue in cerebral stroke. The present study investigated the neuroprotective effect of sesamin (Sn) to reduce brain injury after middle cerebral artery occlusion (MCAO). The middle cerebral artery (MCA) of adult male Wistar rat was occluded for 2 h and reperfused for 22 h. Sesamin is the most abundant lignan in sesame seed oil is a potent antioxidant. Sesamin (30 mg/kg) was given orally twice, 30 min before the onset of ischemia and 12 h after reperfusion. The initial investigations revealed that sesamin reduced the neurological deficits in terms of behavior and reduced the level of thiobarbituric acid reactive species (TBARS), and protein carbonyl (PC) in the different areas of the brain when compared with the MCAO group. A significantly depleted level of glutathione and its dependent enzymes (glutathione peroxidase [GPx] and glutathione reductase [GR]) in MCAO group were protected significantly in MCAO group treated with sesamin. The present study suggests that sesamin may be able to attenuate the ischemic cell death and plays a crucial role as a neuroprotectant in regulating levels of reactive oxygen species in the rat brain. Thus, sesamin may be a potential compound in stroke therapy.     

Effect of total flavonoids of Radix Ilicis pubescentis on cerebral ischemia reperfusion model

This paper aims to observe the effects of total flavonoids of Radix Ilicis pubescentis on mouse model of cerebral ischemia reperfusion. Mice were orally given different doses of total flavonoids of Radix Ilicis pubescentis 10 d, and were administered once daily. On the tenth day after the administration of 1 h in mice after anesthesia, we used needle to hook the bilateral common carotid artery (CCA) for 10 min, with 10 min ischemia reperfusion, 10 min ischemia. Then we restored their blood supply, copy the model of cerebral ischemia reperfusion; We then had all mice reperfused for 24 h, and then took their orbital blood samples and measured blood rheology. We quickly removed the brain, with half of the brain having sagittal incision. Then we fixed the brains and sectioned them to observe the pathological changes of brain cells in the hippocampus and cortex. We also measured the other half sample which was made of brain homogenate of NO, NOS, Na⁺-K⁺-, ATP enzyme Mg²⁺-ATPase and Ca²⁺-ATPase. Acupuncture needle hook occlusion of bilateral common carotid arteries can successfully establish the model of cerebral ischemia reperfusion. After comparing with the model mice, we concluded that Ilex pubescens flavonoids not only reduce damage to the brain nerve cells in the hippocampus and cortex, but also significantly reduce the content of NO in brain homogenate, the activity of nitric oxide synthase (NOS) and increases ATP enzyme activity (P < 0.05, P < 0.01). In this way, cerebral ischemia reperfusion injury is improved. Different dosages of Ilex pubescens flavonoids on mouse cerebral ischemia reperfusion model have good effects.     

Optimization of cyclic sulfamide derivatives as 11β-hydroxysteroid dehydrogenase 1 inhibitors for the potential treatment of ischemic brain injury

The 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), a cortisol regenerating enzyme that amplifies tissue glucocorticoid levels, plays an important role in diabetes, obesity, and glaucoma and is recognized as a potential therapeutic target for various disease conditions. Moreover, a recent study demonstrated that selective 11β-HSD1 inhibitor can attenuate ischemic brain injury. This prompted us to optimize cyclic sulfamide derivative for aiming to treat ischemic brain injury. Among the synthesized compounds, 6e has an excellent in vitro activivity with an IC₅₀ value of 1 nM toward human and mouse 11β-HSD1 and showed good 11β-HSD1 inhibition in ex vivo study using brain tissue isolated from mice. Furthermore, in the transient middle cerebral artery occlusion model in mice, 6e treatment significantly attenuated infarct volume and neurological deficit following cerebral ischemia/reperfusion injury. Additionally, binding modes of 6e for human and mouse 11β-HSD1 were suggested.     

Minocycline inhibits 5-lipoxygenase expression and accelerates functional recovery in chronic phase of focal cerebral ischemia in rats

AimsWe previously reported that minocycline attenuates acute brain injury and inflammation after focal cerebral ischemia, and this is partly mediated by inhibition of 5-lipoxygenase (5-LOX) expression. Here, we determined the protective effect of minocycline on chronic ischemic brain injury and its relation with the inhibition of 5-LOX expression after focal cerebral ischemia.Main methodsFocal cerebral ischemia was induced by 90 min of middle cerebral artery occlusion followed by reperfusion for 36 days. Minocycline (45 mg/kg) was administered intraperitoneally 2 h and 12 h after ischemia and then every 12 h for 5 days. Sensorimotor function was evaluated 1–28 days after ischemia and cognitive function was determined 30–35 days after ischemia. Thereafter, infarct volume, neuron density, astrogliosis, and 5-LOX expression in the brain were determined.Key findingsMinocycline accelerated the recovery of sensorimotor and cognitive functions, attenuated the loss of neuron density, and inhibited astrogliosis in the boundary zone around the ischemic core, but did not affect infarct volume. Minocycline significantly inhibited the increased 5-LOX expression in the proliferated astrocytes in the boundary zone, and in the macrophages/microglia in the ischemic core.SignificanceMinocycline accelerates functional recovery in the chronic phase of focal cerebral ischemia, which may be partly associated with the reduction of 5-LOX expression.     

Changes of ginsenosides in Korean red ginseng (Panax ginseng) fermented by Lactobacillus plantarum M1

To obtain microorganisms for the microbial conversion of ginsenosides in red ginseng powder (RGP), Lactobacillus species (M1–M4 and P1–P4) were isolated from commercial ginseng products. Strain M1 was determined to be L. plantarum by 16S rRNA sequencing. Red ginseng powder (RGP) fermented by L. plantarum M1 had a high total content of ginsenosides (142.4 mg/g) as compared to the control (121.8 mg/g). In particular, the ginsenoside metabolites Rg3, Rg5, Rk1, Compound K (CK), Rh1, and Rg2 showed a high level in the fermented RGP (65.5 mg/g) compared to the control (32.7 mg/g). During fermentation for 7 days, total sugar content decreased from 8.55 mg/g to 4 mg/g, uronic acid content reached its maximum (53.43 μg/g) at 3 days, and total ginsenoside content increased to 176.8 mg/g at 4 days. In addition, ginsenoside metabolites increased from 38.0 mg/g to 83.4 mg/g at 4 days of fermentation. Using everted instestinal sacs of rats, the fermented red ginseng showed a high transport level (10.3 mg of polyphenols/g sac) compared to non-fermented red ginseng (6.67 mg of polyphenols/g sac) after 1 h. These results confirm that fermentation with L. plantarum M1 is very useful for preparing minor ginsenoside metabolites while being safe for foods.     

Biotransformation pathways of ginsenoside Rb1 to compound K by β-glucosidases in fungus Paecilomyces Bainier sp. 229

Ginsenoside Rb1 is the most abundant ginsenoside in Panax (ginseng). The hydrolysis of this ginsenoside produces compound K, the biologically active ginsenoside of ginseng. We previously identified a fungus Paecilomyces Bainier sp. 229 (sp. 229), which can efficiently convert ginsenoside Rb1 to compound K. In this report, the ginsenoside hydrolyzing β-glucosidases were isolated from sp. 229 and the pathway of the biotransformation of ginsenoside Rb1 to compound K by sp. 229 was investigated. Based on reverse-phase HPLC and TLC analysis, we found the main metabolic pathway is as follows: ginsenoside Rb1 → ginsenoside Rd → ginsenoside F2 → compound K. Moreover, the results showed that there were other metabolic pathways: ginsenoside Rb1 → ginsenoside XVII → ginsenoside F2 → compound K and ginsenoside Rb1 → ginsenoside Rg3 → ginsenoside Rh2. These processes would allow the specific bioconversion of ginsenoside Rb1 to various ginsenosides using an appropriate combination of specific microbial enzymes.     

Intervention action of total flavonoids from root of Ilex pubescens in cerebral ischemic tolerance with blood stasis

The aim of this study was to explore the action characters of total flavonoids from MDQ on cerebral ischemic tolerance with blood stasis. Fully understanding the mechanism of action of total flavonoids from MDQ is helpful for the development of new drugs and the utilization of resources. Male Wistar rat model of blood stasis was established by injecting dexamethasone into the intramuscular side of the thigh. Then they were given related drugs via an intragastric administration for a successive 10 days. After 7 days, the following occurred: firstly, the method of blocking the bilateral common carotid artery (CCA) was used for 10 min, followed by a restoration of perfusion. After 72 h, we performed a temporary occlusion of the rat’s middle cerebral artery for 2 h with an intraluminal thread method. This was followed by reperfusion for 24 h, respectively, to establish the rat model of cerebral ischemic tolerance with blood stasis. Viscosity of the whole blood was measured after the last administration was given blood. Brain was removed, and then the activity of ATP enzyme and T-SOD was determined. To observe the pathological changes of the hippocampus area by HE staining, and the expression of Bcl-2 and Bax were observed by immunohistochemical method. The rat model of cerebral ischemic tolerance with blood stasis was copied successfully. The whole blood viscosity, the activity of NOS, the content of Gluin in the ischemic brain in the IPC model group and the ischemia–reperfusion group were increased significantly. The activity of ATPase was decreased significantly. Compared with the ischemia–reperfusion model group, the activity of ATPase and the whole blood viscosity in the ischemic preconditioning (IPC) group were increased significantly. The activity of NOS and the content of Gluin were decreased significantly. The degree of pathological injury of the brain tissue was also relieved significantly. Total flavonoids of MDQ were used, improving blood circulation, improving energy metabolism, activating endogenous anti-oxidative capability, enhancing the antiapoptotic effect, and relieving the injury of the nerve cell. Hence, the use of MDQ flavonoids improves the tolerance ability of cerebral ischemia.     

Mitofusin 2 ameliorates hypoxia-induced apoptosis via mitochondrial function and signaling pathways

Mitochondrial dynamics play a critical role in mitochondrial function and signaling. Although mitochondria play a critical role in hypoxia/ischemia, the further mechanisms between mitochondrial dynamics and ischemia are still unclear. The current study aimed to determine the role of mitofusin 2, a key regulator of mitochondrial fusion, in a hypoxic model and to explore a novel strategy for cerebral ischemia via modulation of mitochondrial dynamics. To the best of our knowledge, this is the first study to investigate both mitochondrial function and molecular pathways to determine the role of mitofusin 2 in hypoxia-induced neuronal apoptosis. In vivo, C57BL/6 mice (male, 19–25 g) underwent a permanent middle cerebral artery occlusion for 12 or 24 h (n = 6 per group). In vitro, cobalt chloride was used to mimic hypoxia in immortalized hippocampal neurons. Down- or up-regulation of Mfn2 was induced to investigate the role of Mfn2 in hypoxia, especially in mitochondrial function and signaling pathways. The findings demonstrated that decreased mitofusin 2 occurred both in vivo and in vitro hypoxic models; second, the anti-apoptotic effect of Mfn2 may work via restoration of mitochondrial function; third, the modulation of the B Cell Leukemia 2/Bcl-2 Associated X protein and extracellular signal-regulated kinase 1/2 signaling pathways highlight the role of Mfn2 in signaling pathways beyond fusion. In summary, depletion of mitofusin 2 would lead to apoptosis both in normal or hypoxic conditions; however, mitofusin 2 overexpression could attenuate hypoxia-induced apoptosis, which represents a potential novel strategy for neuroprotection against ischemic brain damage.     

Neuroprotective effect of glutamate-substituted analog of gramicidin A is mediated by the uncoupling of mitochondria

BackgroundReactive oxygen species are grossly produced in the brain after cerebral ischemia and reperfusion causing neuronal cell death. Mitochondrial production of reactive oxygen species is nonlinearly related to the value of the mitochondrial membrane potential with significant increment at values exceeding 150 mV. Therefore, limited uncoupling of oxidative phosphorylation could be beneficial for cells exposed to deleterious oxidative stress-associated conditions by preventing excessive generation of reactive oxygen species.MethodsProtonophoric and uncoupling activities of different peptides were measured using pyranine-loaded liposomes and isolated mitochondria. To evaluate the effect of glutamate-substituted analog of gramicidin A ([Glu1]gA) administration on the brain ischemic damage, we employed the in vitro model of neuronal hypoxia using primary neuronal cell cultures and the in vivo model of cerebral ischemia induced in rats by the middle cerebral artery occlusion.Results[Glu1]gA was the most effective in proton-transferring activity among several N-terminally substituted analogs of gramicidin A tested in liposomes and rat brain and liver mitochondria. The peptides were found to be protective against ischemia-induced neuronal cell death and they lowered mitochondrial membrane potential in cultured neurons and diminished reactive oxygen species production in isolated brain mitochondria. The intranasal administration of [Glu1]gA remarkably diminished the infarct size indicated in MR-images of a brain at day 1 after the middle cerebral artery occlusion. In [Glu1]gA-treated rats, the ischemia-induced brain swelling and behavioral dysfunction were significantly suppressed.ConclusionsThe glutamate-substituted analogs of gramicidin A displaying protonophoric and uncoupling activities protect neural cells and the brain from the injury caused by ischemia/reperfusion.General significance[Glu1]gA may be potentially used as a therapeutic agent to prevent neuron damage after stroke.     

Overexpression of HSPA12B protects against cerebral ischemia/reperfusion injury via a PI3K/Akt-dependent mechanism

Background and purpose: HSPA12B is a newly discovered member of the Hsp70 family proteins. This study investigated the effects of HSPA12B on focal cerebral ischemia/reperfusion (I/R) injury in mice. Methods: Transgenic mice overexpressing human HSPA12B (Tg) and wild-type littermates (WT) were subjected to 60 min of middle cerebral artery occlusion to induce ischemia and followed by reperfusion (I/R). Neurological deficits, infarct volumes and neuronal death were examined at 6 and 24 hrs after reperfusion. Blood–brain-barrier (BBB) integrity and activated cellular signaling were examined at 3 hrs after reperfusion. Results: After cerebral I/R, Tg mice exhibited improvement in neurological deficits and decrease in infarct volumes, when compared with WT I/R mice. BBB integrity was significantly preserved in Tg mice following cerebral I/R. Tg mice also showed significant decreases in cell injury and apoptosis in the ischemic hemispheres. We observed that overexpression of HSPA12B activated PI3K/Akt signaling and suppressed JNK and p38 activation following cerebral I/R. Importantly, pharmacological inhibition of PI3K/Akt signaling abrogated the protection against cerebral I/R injury in Tg mice. Conclusions: The results demonstrate that HSPA12B protects the brains from focal cerebral I/R injury. The protective effect of HSPA12B is mediated though a PI3K/Akt-dependent mechanism. Our results suggest that HSPA12B may have a therapeutic potential against ischemic stroke.     

Plumbagin inhibits neuronal apoptosis,intimal hyperplasia and also suppresses TNF-α/NF-κB pathway induced inflammation and matrix metalloproteinase-2/9 expression in rat cerebral ischemia

Cerebral ischemic damage and infarction are well documented in stroke, which is presenting a foremost health concern globally with very high mortality and morbidity rates. Mechanisms that are associated with excitotoxicity, inflammation and oxidative stress are found to be critically involved in ischemic damage. Adverse effects of current therapies are imposing the need in development of neuroprotective agents that are very effective. To explore this we experimentally induced ischemic brain injury and investigated the effects of plumbagin. Induction of cerebral infarction and ischemia-reperfusion (I/R) was done by middle cerebral artery occlusion (MCAO) in Sprague-Dawley rats. Plumbagin (50, 100 or 200 mg/kg b.wt) was intragastrically administered for 9 days before ischemia induction and an hour prior on the day of ischemic insult. Plumbagin treatment attenuated pulmonary edema, neuronal apoptosis and reduced cerebral infarct volume. Cleaved caspase-3 and apoptotic cascade protein expressions were regulated. Overproduction of pro-inflammatory cytokines (TNF-α, IL-1β and IL-6) and nitric oxide (NO) following I/R were reduced. Prior plumbagin administration had down-regulated NF-κB signalling and MMP-2 and MMP-9 expression. Overall, the results reveal the potent neuroprotective efficacy of plumbagin against I/R-induced brain injury via effectively modulating apoptotic pathways, MMPs and neuro-inflammatory cascades.     

Antioxidative effects of Panax notoginseng saponins in brain cells

Oxidative stress resulting from accumulation of reactive oxygen species (ROS) is involved in cell death associated with neurological disorders such as stroke, Alzheimer's disease and traumatic brain injury. Antioxidant compounds that improve endogenous antioxidant defenses have been proposed for neural protection. The purpose of this study was to investigate the potential protective effects of total saponin in leaves of Panax notoginseng (LPNS) on oxidative stress and cell death in brain cells in vitro. Lactate dehydrogenase (LDH) assay indicated that LPNS (5 μg/ml) reduced H₂O₂-induced cell death in primary rat cortical astrocytes (23 ± 8% reduction in LDH release vs. control). Similar protection was found in oxygen and glucose deprivation/reoxygenation induced SH-SY5Y (a human neuroblastoma cell line) cell damage (78 ± 7% reduction vs. control). The protective effects of LPNS in astrocytes were associated with attenuation of reactive oxygen species (ROS) accumulation. These effects involved activation of Nrf2 (nuclear translocation) and upregulation of downstream antioxidant systems including heme oxygenase-1 (HO-1) and glutathione S-transferase pi 1 (GSTP1). These results demonstrate for the first time that LPNS has antioxidative effects which may be neuroprotective in neurological disorders.     

The influence of stachydrine hydrochloride on the reperfusion model of mice with repetitive cerebral ischemia

To study the influence of stachydrine hydrochloride on the inflammatory cytokines and tissue morphology of the re-perfusion model of mice with repetitive cerebral ischemia and probe into the protection mechanism of stachydrine hydrochloride for cerebral ischemia reperfusion impairment. Build a repetitive cerebral ischemia reperfusion model by first blocking the common carotid artery on both sides for 10 min, then resuming perfusion for 10 min and then blocking the common carotid artery on both sides again for 10 min. Before the operation, all the mice in the Nimodipine group, and the big, medium and small stachydrine hydrochloride dose groups were given corresponding gastric perfusion, the mice in the sham operation group and the modeled groups were at the same time given 0.5% sodium carboxymethyl cellulose for gastric perfusion of the same volume. The medicine was fed daily for 7 consecutive days. The model was built 1 h after the last feed and the perfusion continued for 24 h after the operation. Then the death rate of the mice was calculated. The mouse brains were taken out to test the ICAM-1 level and the TNF-α level, and the serum was taken out to test the NSE level and the MPO level. The tissue morphology changes were also observed. All the repetitive cerebral ischemia reperfusion models were successfully duplicated. The stachydrine hydrochloride in all the dose groups significantly reduced the death rates of big and small mice, reduced the level of ICAM-1 and the level of TNF-α in the brain tissues and the NSE level and the MPO level in the serum, significantly alleviating the pathological impairment in the hippocampus. Stachydrine hydrochloride can significantly reduce the death rate of mice, improve the pathological changes in the hippocampus, inhibit inflammatory reactions after ischemia, thus reducing the re-perfusion impairment after cerebral ischemia.     

人参皂苷Rg1对脑缺血再灌注大鼠Caspase-3蛋白表达的影响

目的探讨人参皂苷Rg1对脑缺血再灌注大鼠脑组织半胱氨酸天冬氨酸酶3(Caspase-3)表达的影响。方法将大鼠随机分为假手术组、模型组、人参皂苷Rg110、20、40mg/kg组、尼莫地平组,每组10只。采用线栓法栓塞大脑中动脉2h制作大鼠脑缺血再灌注模型;观察再灌注22h后神经功能缺损评分;应用免疫组化、免疫印迹法检测大脑皮层缺血半暗带Caspase-3的表达。结果(1)假手术组、模型组、人参皂苷Rg110、20、40mg/kg组和尼莫地平组神经功能缺损评分分别为0、2.8±0.9、2.1±0.9、1.5±0.7、1.3±1.1、1.5±0.7,差异有统计学意义(P0.05)。人参皂苷Rg120、40mg/kg组与模型组比较,差异有统计学意义(P0.05);人参皂苷Rg110mg/kg组与尼莫地平组比较,差异有统计学意义(P0.05);人参皂苷Rg120、40mg/kg组与尼莫地平组比较,差异均无统计学意义(P0.05)。(2)免疫组化和免疫印迹结果显示各组大鼠皮层缺血半暗带均有Caspase-3的表达,其中假手术组仅有少量表达,模型组表达最多。与模型组比较,人参皂苷Rg1各剂量组及尼莫地平组Caspase-3表达量减少,差异有统计学意义(P0.05);与尼莫地平组比较,人参皂苷Rg110mg/kg组的Caspase-3表达量显著增高,40mg/kg组显著降低(P0.05),而20mg/kg组则差异无统计学意义(P0.05)。结论人参皂苷Rg1防治脑缺血再灌注的机制与抑制脑组织Caspase-3表达有关,且以高剂量效果较好。     

3-Bromo-7-nitroindazole attenuates brain ischemic injury in diabetic stroke via inhibition of endoplasmic reticulum stress pathway involving CHOP

AimsThe role of nitric oxide (NO) and endoplasmic reticulum (ER) stress has been implicated in the pathogenesis of cerebral ischemic/reperfusion (I/R) injury and diabetes. The aim of the study was to investigate the neuroprotective potential of 3-bromo-7-nitroindazole (3-BNI), a potent and selective neuronal nitric oxide synthase (nNOS) inhibitor against ER stress and focal cerebral I/R injury associated with comorbid type 2 diabetes in-vivo.Main methodsType 2 diabetes was induced by feeding high-fat diet and streptozotocin (35 mg/kg) treatment in rats. Focal cerebral ischemia was induced by 2 h middle cerebral artery occlusion (MCAO) followed by 22 h of reperfusion. Immunohistochemistry and western blotting methods were employed for the detection and expression of ER stress/apoptosis markers [78 kDa glucose regulated protein (GRP78) and CCAAT/enhancer binding protein homologous protein (CHOP)]. TUNEL assay for DNA fragmentation was also performed.Key findingsThe diabetic rats subjected to cerebral I/R had prominent neurological damage and functional deficits compared with sham-operated rats. Massive DNA fragmentation was observed in ischemic penumbral region of diabetic brains. Concomitantly, the enhanced immunoreactivity and expression of ER stress/apoptosis markers were noticed. 3-BNI (30 mg/kg, i.p.) treatment significantly inhibited the cerebral infarct, edema volume and improved functional recovery of neurological deficits. The neuroprotection was further evident by lesser DNA fragmentation with a concomitant reduction of GRP78 and CHOP.SignificanceThe study demonstrates the neuroprotective potential of 3-BNI in diabetic stroke model which may be partly due to inhibition of ER stress pathway involving CHOP.