Sesamin and vitamin E ameliorate aortic endothelial dysfunction rats induced by D-galactose and aluminum trichloride via regula?tion of endothelial nitric oxide synthase and NAD(P)H oxidase 4 / 中国药理学与毒理学杂志

OBJECTIVE To observe the protective effect of sesamin (Ses) and vitamin E (Vit E) against aortic endothelial dysfunction in rats induced by D-galactose (D-gal) and aluminum trichloride (AlCl3), and explore its conceivable mechanisms. METHODS A model of aortic endothelial dysfunction rats was established by D-gal (180 mg · kg-1, ip) combined with AlCl3 (15 mg · kg-1, ig) for 84 d. Model rats were randomly divided into model, model+Vit E 10 mg·kg-1, model+Ses 160 mg·kg-1, and model+Ses 160 mg · kg-1+Vit E 10 mg · kg-1 groups. After 70 d of treatment with Ses and Vit E, systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean blood pressure (MBP) were measured by tail cuff. The rats were anesthetized by sodium pentobarbital (30 mg·kg-1, ip). Thoracic aortas from the rats were removed and divided into two parts (3 mm in length). The relaxation of the aortic ring induced by acetylcholine (ACh) and sodium nitroprusside was measured. The primary pathologic changes in the aorta were observed by HE staining. Total antioxidant capacity (T-AOC), hydrogen peroxide (H2O2) and nitric oxide (NO) in serum were measured by colorimetric analysis. The expression of endothelial nitric oxide synthase (eNOS) positive cells in the aorta were measured by immunohistochemistry. The expres?sions of eNOS and NAD(P)H oxidase 4 (NOX4) protein in the aortal were detected by Western blotting. RESULTS Compared with the model group, the relaxation response with increase in ACh concentra?tion (1×10-7-1×10-4 mol·L-1) was enhanced (P<0.01) in model+Ses+Vit E, SBP, DBP and MBP decreased (P<0.01), the serum T-AOC and NO level were increased (P<0.01), the serum H2O2 levels were reduced (P<0.01), the eNOS expression was increased (P<0.01) and NOX4 expression was reduced (P<0.01) in each treatment group. Compared with model+Ses, the SBP, DBP and MBP were lower (P<0.01 or P<0.05), the serum H2O2 level was lower (P<0.01), the serum NO level was increased (P<0.05), the eNOS expression level was higher (P<0.01) and the NOX4 expression level was reduced (P<0.05) in model+Ses+Vit E. Compared with the model+Vit E, the serum T-AOC and NO levels were increased (P<0.05), the serum H2O2 level was lower (P<0.01), eNOS expression was increased (P<0.01) and NOX4 expression was reduced (P<0.05) in model+Ses+Vit E group. CONCLUSION Ses and Vit E can ameliorate aortic endothelial dysfunction of rats induced by D-gal and AlCl3 via the regulation of eNOS and NOX4.

Resveratrol attenuates lipopolysaccharide-induced dysfunction of blood-brain barrier in endothelial cells via AMPK activation

Resveratrol, a phytoalexin, is reported to activate AMP-activated protein kinase (AMPK) in vascular cells. The blood-brain barrier (BBB), formed by specialized brain endothelial cells that are interconnected by tight junctions, strictly regulates paracellular permeability to maintain an optimal extracellular environment for brain homeostasis. The aim of this study was to elucidate the effects of resveratrol and the role of AMPK in BBB dysfunction induced by lipopolysaccharide (LPS). Exposure of human brain microvascular endothelial cells (HBMECs) to LPS (1 µg/ml) for 4 to 24 hours week dramatically increased the permeability of the BBB in parallel with lowered expression levels of occluding and claudin-5, which are essential to maintain tight junctions in HBMECs. In addition, LPS significantly increased the reactive oxygen species (ROS) productions. All effects induced by LPS in HBVMCs were reversed by adenoviral overexpression of superoxide dismutase, inhibition of NAD(P) H oxidase by apocynin or gain-function of AMPK by adenoviral overexpression of constitutively active mutant (AMPK-CA) or by resveratrol. Finally, upregulation of AMPK by either AMPK-CA or resveratrol abolished the levels of LPS-enhanced NAD(P)H oxidase subunits protein expressions. We conclude that AMPK activation by resveratrol improves the integrity of the BBB disrupted by LPS through suppressing the induction of NAD(P)H oxidase-derived ROS in HBMECs.

Effect of globular adiponectin on the function of NIT-I cells under high glucose medium / 中华内分泌代谢杂志

The effect of globular adiponectiin (gAd)on the function of NIT-1 cells under high glucose medium was investigated. The results showed that gad could completely block the increase of NADPH oxidase components p47phox expression and recover mRNA expression of pancreatic duodenal homeobox-I ,paired box gene 6,glucose transpoter 2,and glucokinase except neurogenic differentiation factor 1 (P<0.05 or P<0.01). Whereas,impaired insulin secretion and mRNA expression at high glucose concentration were not significantly improved by gAd.

High Glucose and/or Free Fatty Acid Damage Vascular Endothelial Cells via Stimulating of NAD(P)H Oxidase-induced Superoxide Production from Neutrophils / 당뇨병

BACKGROUND: Oxidative stress and inflammation are important factors in the pathogenesis of diabetes and contribute to the development of diabetic complications. To understand the mechanisms that cause vascular complications in diabetes, we examined the effects of high glucose and/or free fatty acids on the production of superoxide from neutrophils and their role in endothelial cell damage. METHODS: Human neutrophils were incubated in the media containing 5.5 mM D-glucose, 30 mM D-glucose, 3 nM oleic acid, or 30 microM oleic acid for 1 hour to evaluate superoxide production through NAD(P)H oxidase activation. Human aortic endothelial cells were co-cultured with neutrophils exposed to high glucose and oleic acid. We then measured neutrophil adhesion to endothelial cells, neutrophil activation and superoxide production, neutrophil-mediated endothelial cell cytotoxicity and subunits of neutrophil NAD(P)H oxidase. RESULTS: After 1 hour of incubation with various concentrations of glucose and oleic acid, neutrophil adherence to high glucose and oleic acid-treated endothelial cells was significantly increased compared with adhesion to low glucose and oleic acid-treated endothelial cells. Incubation of neutrophils with glucose and free fatty acids increased superoxide production in a dose-dependent manner. High glucose and oleic acid treatment significantly increased expression of the membrane components of NAD(P)H oxidase of neutrophil (gp91(phox)). Endothelial cells co-cultured with neutrophils exposed to high glucose and oleic acid showed increased cytolysis, which could be prevented by an antioxidant, N-acetylcysteine. CONCLUSION: These results suggest that high glucose and/orfree fatty acidsincrease injury of endothelial cells via stimulating NAD(P)H oxidase-induced superoxide production from neutrophils.

Expression of NAD(P)H Oxidase Subunits and Their Contribution to Cardiovascular Damage in Aldosterone/Salt-Induced Hypertensive Rat

NAD(P)H oxidase plays an important role in hypertension and its complication in aldosterone-salt rat. We questioned whether NAD(P)H oxidase subunit expression and activity are modulated by aldosterone and whether this is associated with target- organ damage. Rats were infused with aldosterone (0.75 microgram/hr/day) for 6 weeks and were given 0.9% NaCl+/-losartan (30 mg/kg/day), spironolactone (200 mg/kg/ day), and apocynin (1.5 mM/L). Aldosterone-salt hypertension was prevented completely by spironolactone and modestly by losartan and apocynin. Aldosterone increased aortic NAD(P)H oxidase activity by 34% and spironolactone and losartan inhibited the activity. Aortic expression of the subunits p47(phox), gp91(phox), and p22(phox) increased in aldosterone-infused rats by 5.5, 4.7, and 3.2-fold, respectively, which was decreased completely by spironolactone and partially by losartan and apocynin. Therefore, the increased expression of NAD(P)H oxidase may contribute to cardiovascular damage in aldosterone-salt hypertension through the increased expression of each subunit.

The Role of Janus Kinase in Superoxide-mediated Proliferation of Diabetic Vascular Smooth Muscle Cells

To elucidate a potential molecular link between diabetes and atherosclerosis, we investigated the role of Janus tyrosine kinase (JAK) for NAD(P)H oxidase-derived superoxide generation in the enhanced proliferative capacity of vascular smooth muscle cells (VSMC) of Otsuka Long-Evans Tokushima Fatty (OLETF) rat, an animal model of type 2 diabetes. An enhanced proliferative response to 10% fetal bovine serum (FBS) and superoxide generation with an increased NAD(P)H oxidase activity were observed in diabetic (OLETF) VSMC. Both the enhanced proliferation and superoxide generation in diabetic VSMC were significantly attenuated by AG490, JAK2 inhibitor, and PP2, Src kinase inhibitor. Tyrosine phosphorylation of proteins in diabetic VSMC, especially JAK2, was increased compared to control VSMC. Furthermore, the enhanced NAD(P)H oxidase activity in diabetic VSMC was significantly attenuated by AG490 in a dose-dependent manner. Together, these results indicate that the signal pathway which leads to diabetes-associated activation of Src kinase/JAK is critically involved in the diabetic VSMC proliferation through NAD(P)H oxidase activation and superoxide generation.

Enhanced Expression of Cell Adhesion Molecules in the Aorta of Diabetic Mice is Mediated by gp91phox-derived Superoxide

Endothelial activation and subsequent recruitment of inflammatory cells are important steps in atherogenesis. The increased levels of cell adhesion molecules (CAM) have been identified in diabetic vasculatures, but the underlying mechanisms remain unclear. To determine the relationship among vascular production of superoxide, expression of CAM and diabetes, superoxide generation and expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), E- and P-selectin in the aorta from control (C57BL/6J) and diabetic mice (ob/ob) were measured. In situ staining for superoxide using dihydroethidium showed an increased superoxide production in diabetic aorta, accompanied with an enhanced NAD (P) H oxidase activity. Immunohistochemical analysis revealed that the endothelial expression of ICAM-1 (3.5+/-0.4) and VCAM-1 (3.8+/-0.3) in diabetic aorta was significantly higher than those in control aorta (0.9+/-0.5 and 1.6+/-0.3, respectively), accompanied with the enhanced expression of gp91phox, a membrane subunit of NAD (P) H oixdase. Furthermore, there was a strong positive correlation (r=0.89, P< 0.01 in ICAM-1 and r=0.88, P< 0.01 in VCAM-1) between ICAM-1/VCAM-1 expression and vascular production of superoxide. The present data indicate that the increased production of superoxide via NAD (P) H oxidase may explain the enhanced expression of CAM in diabetic vasculatures.

Gene Transfer of Cu/ZnSOD to Cerebral Vessels Prevents Subarachnoid Hemorrhage-induced Cerebral Vasospasm

The preventive effects of gene transfer of human copper/zinc superoxide dismutase (Cu/ZnSOD) on the development of cerebral vasospasm after subarachnoid hemorrhage (SAH) were examined using a rat model of SAH. An experimental SAH was produced by injecting autologous arterial blood twice into the cisterna magna, and the changes in the diameter of the middle cerebral artery (MCA) were measured. Rats subjected to SAH exhibited a decreased diameter with an increased wall thickness of MCA that were significantly ameliorated by pretreatment with diphenyleneiodonium (DPI, 10microM), an inhibitor of NAD (P) H oxidase. Furthermore, application of recombinant adenovirus (100microliter of 1 x 1010 pfu/ml, intracisternally), which encodes human Cu/ZnSOD, 3 days before SAH prevented the development of SAH-induced vasospasm. Our findings demonstrate that SAH-induced cerebral vasospasm is closely related with NAD (P) H oxidase-derived reactive oxygen species, and these alterations can be prevented by the recombinant adenovirus-mediated transfer of human Cu/ZnSOD gene to the cerebral vasculature.

Involvement of NAD (P) H Oxidase in a Potential Link between Diabetes and Vascular Smooth Muscle Cell Proliferation

The cellular mechanisms that contribute to the acceleration of atherosclerosis in diabetes are poorly understood. Therefore, the potential mechanisms involved in the diabetes-dependent increase in vascular smooth muscle cell (VSMC) proliferation was investigated. Using primary culture of VSMC from streptozotocin-induced diabetic rat aorta, cell proliferation assay showed two-fold increase in cell number accompanied with enhanced superoxide generation compared to normal VSMC, 2 days after plating. Both the increased superoxide production and cell proliferation in diabetic VSMC were significantly attenuated by not only tiron (1 mM), a superoxide scavenger, but also by diphenyleneiodonium (DPI; 10micrometer), an NAD (P) H oxidase inhibitor. NAD (P) H oxidase activity in diabetic VSMC was significantly higher than that in control cell, accompanied with increased mRNA expression of p22phox, a membrane subunit of oxidase. Furthermore, inhibition of p22phox expression by transfection of antisense p22phox oligonucleotides into diabetic VSMC resulted in a decrease in superoxide production, which was accompanied by a significant inhibition of cell proliferation. Based on these results, it is suggested that diabetes-associated increase in NAD (P) H oxidase activity via enhanced expression of p22phox contributes to augmented VSMC proliferation in diabetic rats.

Involvement of Vascular NAD(P)H Oxidase-derived Superoxide in Cerebral Vasospasm after Subarachnoid Hemorrhage in Rats

The role of vascular NAD(P)H oxidase in subarachnoid hemorrhage (SAH)-induced vasospasm in the basilar artery was examined in a rat model. Arterial vasospasm characterized by increased wall thickness and decreased lumen size was observed at 5 to 7 days after 2nd injection of blood into cisterna magna, and these changes were significantly ameliorated by pretreatment of diphenyleneiodonium (DPI, 25microl of 100microM), an inhibitor of NAD(P)H oxidase. To determine the time course of changes in the vascular NAD(P)H oxidase activity, cerebral vasculature was isolated at different time intervals from 12 hrs to 14 days after injection of autologous blood. At 24 hrs after the second injection of blood, the NAD(P)H oxidase activity was markedly increased with an enhanced membrane translocation of p47phox, but by 48 hours both the enzyme activity and p47phox translocation regained normal values, and were remained unchanged up to 14 days after SAH. However, no significant changes in the expression of p22phox mRNA was observed throughout the experiments. These findings suggest that the activation of NAD(P)H oxidase by which assembly of the oxidase components enhanced and subsequent production of superoxide in the early stages of SAH might contribute to the delayed cerebral vasospasm in SAH rats.