Swertiamarin attenuates paraquat-induced pulmonary epithelial-like cell apoptosis via NOX4-mediated regulation of redox and mitochondrial function

Abstract The aim of the present study was to investigate the effect of swertiamarin (STM) in attenuating paraquat (PQ)-induced human lung alveolar epithelial-like cell (A549) apoptosis and the underlying mechanisms. A549 cells were pretreated with different concentrations of STM for 2 hr and then cultured with or without PQ (700 µM) for 24 hr. Cell survival was determined using the CCK8 assay. Morphological changes, MDA content, inflammatory factors, fibrogenesis parameters, apoptosis rates, redox status and mitochondrial membrane potential (MMP) were evaluated. The expression of several genes involved in the modulation of redox status was measured by Western blotting. Cell viability and MMP were decreased, but the apoptosis rate and DCFH oxidation were elevated by PQ exposure. STM pretreatment notably increased cell viability and MMP and reduced the apoptosis rate and DCFH oxidation. Furthermore, TLR4- NOX4 signaling was significantly inhibited by STM. The downregulation of NOX4 by siRNA exerted the same protective effects as STM. This study provides the first evidence that STM attenuates PQ-induced pulmonary epithelial-like cell apoptosis via NOX4-mediated regulation of redox and mitochondrial function

Resveratrol inhibits hypoxia-induced oxidative stress and proliferation in pulmonary artery smooth muscle cells through the HIF-1α/NOX4/ROS signaling pathway / 生理学报

The purpose of the present study was to determine the effects of resveratrol on hypoxia-induced oxidative stress and proliferation in pulmonary artery smooth muscle cells (PASMCs) and the underlying mechanism. Primary rat PASMCs were isolated and cultured in vitro and pretreated with different concentrations of resveratrol (10, 20, and 40 µmol/L) or the NADPH oxidase (NOX) inhibitor VAS2870 (10 µmol/L) for 0.5 h. The cells were then cultured under normoxia (21% O

Research on the mechanism of high glucose affecting the apoptosis of schwann cells by Nox4 NADPH oxidase / 中国应用生理学杂志

OBJECTIVE@#To investigate the mechanism of high glucose affecting the apoptosis of schwann cells through Nox4 NADPH oxidase.@*METHODS@#The schwann cells of newborn Wistar rats were cultured in vitro. The cultured cells were divided into four groups: control group, high-glucose group, NOX4 siRNA group and control siRNA group (n=10). The WST-1 method was used to detect the cell vitality, and the DCFH-DA method was used to detect the contents of intracellular reactive oxygen free radicals (ROS). Nox4 and Caspase3 mRNA expressions were detected by real-time fluorescence quantitative RT-PCR. Nox4 and Caspase3 protein expressions were determined by Western blot.@*RESULTS@#High glucose culture up-regulated Nox4 mRNA and protein expressions of schwann cells, decreased activity of schwann cells, increased intracellular ROS content, and promoted apoptosis by increasing Caspase3 mRNA and protein expressions. NOX4 siRNA blocked the accumulation of ROS in the high glucose cultured schwann cells, and reduced the damage of glucose on cell viability, by inhibiting NOX4 gene expression. NOX4 siRNA also reduced cell apoptosis by down-regulating Caspase3 mRNA and protein expressions.@*CONCLUSION@#Nox4 was involved in the hyperglycemic-induced apoptosis of schwann cells through ROS. The regulation of Nox4 expression or function might be a new way to treat diabetic peripheral neuropathy.

Palmitic acid induces hepatocellular oxidative stress and activation of inflammasomes / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the effect of palmitic acid (PA) on oxidative stress and activation of inflammasomes in hepatocytes.</p><p><b>METHODS</b>To test the dose-dependent effect of PA on normal murine hepatocytes AML12, the cells were treated with 0, 0.15, 0.25 and 0.4 mmol/L of palmitic acid (PA). The cells were also divided into blank control group, 0.25 mmol/L PA group and 0.25 mmol/L PA+N-acetylcysteine (NAC) group to examine the effect of reactive oxygen species (ROS) on the activation of inflammasomes. After 24 h of treatment, lipid accumulation, total ROS, mitochondrial ROS, expression and localization of NOX4, and expressions of inflammasomes and IL-1β were detected in the hepatocytes.</p><p><b>RESULTS</b>Compared with the control cells, PA treatment of the cells significantly increased cytoplasmic lipid accumulation, concentrations of total ROS (12 463.09±2.72 vs 6691.23±2.45, P=0.00) and mitochondrial ROS (64.98±0.94 vs 45.04±0.92, P=0.00), and the expressions of NOX4, NLRP3, ASC, caspase-1, and IL-1β (1603.52±1.32 vs 2629.33±2.57, P=0.00). The mitochondria and NOX4 were found to be co-localized in the cytoplasm. NAC obviously reduced cellular ROS level stimulated by PA (7782.15±2.87 vs 5445.6±1.17, P=0.00) and suppressed the expressions of NLRP3, ASC and caspase-1.</p><p><b>CONCLUSION</b>PA treatment can stimulate lipid accumulation in hepatocytes and induce oxidative stress through NOX4 and mitochondria pathway to activate inflammasomes and stimulate the secretion of IL-1β.</p>

NLRP3 inflammasome mediates angiotension II-induced expression of inflammatory factor interleukin-1β in human umbilical vein endothelial cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of angiotension II (AngII) on the activation of NLRP3 inflammasome and the expression of interleukin-1β (IL-1β) in human umbilical vein endothelial cells (HUVECs).</p><p><b>METHODS</b>HUVECs cultured in vitro were treated with different concentrations of AngII for varying lengths of time to determine the optimal concentration and time for AngII exposure. To test the impact of different agents on the effect of AngII exposure, HUVECs were pretreated with AngII receptor blocker losartan, NAD(P)H inhibitor DPI and H(2)O(2) scavenger CAT, caspase 1 inhibitor YVAD, or NLRP3 siRNA for silencing NLRP3, and the protein levels of NOX4, NLRP3, caspase-1 and IL-1β in HUVECs were analyzed by Western blotting.</p><p><b>RESULTS</b>AngII treatment at the optimal concentration (10(-9) mol/L) for 12 h significantly increased the protein levels of NOX4, NLRP3, caspase1 and IL-1β in HUVECs. Pretreatment with losartan, DPI, CAT, YVAD, or NLRP3 siRNA all attenuated the effects of AngII on the cells.</p><p><b>CONCLUSION</b>AngII can induce vascular inflammation by promoting the production of reactive oxygen species and activating NLRP3 inflammasome to increase the protein expression of IL-1β in HUVECs.</p>

NADPH Oxidase Accounts for Changes in Cerebrovascular Redox Status in Hindlimb Unweighting Rats / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>The roles of cerebrovascular oxidative stress in vascular functional remodeling have been described in hindlimb-unweighting (HU) rats. However, the underlying mechanism remains to be established.</p><p><b>METHODS</b>We investigated the generation of vascular reactive oxygen species (ROS), Nox2/Nox4 protein and mRNA levels, NADPH oxidase activity, and manganese superoxide dismutase (MnSOD) and glutathione peroxidase-1 (GPx-1) mRNA levels in cerebral and mesenteric smooth muscle cells (VSMCs) of HU rats.</p><p><b>RESULTS</b>ROS production increased in cerebral but not in mesenteric VSMCs of HU rats compared with those in control rats. Nox2 and Nox4 protein and mRNA levels were increased significantly but MnSOD/GPx-1 mRNA levels decreased in HU rat cerebral arteries but not in mesenteric arteries. NADPH oxidases were activated significantly more in cerebral but not in mesenteric arteries of HU rats. NADPH oxidase inhibition with apocynin attenuated cerebrovascular ROS production and partially restored Nox2/Nox4 protein and mRNA levels, NADPH oxidase activity, and MnSOD/GPx-1 mRNA levels in cerebral VSMCs of HU rats.</p><p><b>CONCLUSION</b>These results suggest that vascular NADPH oxidases regulate cerebrovascular redox status and participate in vascular oxidative stress injury during simulated microgravit.</p>

Losartan regulates oxidative stress via caveolin-1 and NOX4 in mice with ventilator- induced lung injury / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of losartan in regulating oxidative stress and the underlying mechanism in mice with ventilator-induced lung injury.</p><p><b>METHODS</b>Thirty-six male C57 mice were randomly divided into control group, losartan treatment group, mechanical ventilation model group, and ventilation plus losartan treatment group. After the corresponding treatments, the lung injuries in each group were examined and the expressions of caveolin-1 and NOX4 in the lung tissues were detected.</p><p><b>RESULTS</b>The mean Smith score of lung injury was significantly higher in mechanical ventilation model group (3.3) than in the control group (0.4), and losartan treatment group (0.3); the mean score was significantly lowered in ventilation plus losartan treatment group (2.3) compared with that in the model group (P<0.05). The expressions of caveolin-1 and NOX4 were significantly higher in the model group than in the control and losartan treatment groups (P<0.05) but was obviously lowered after losartan treatment (P<0.05). Co-expression of caveolin-1 and NOX4 in the lungs was observed in the model group, and was significantly decreased after losartan treatment.</p><p><b>CONCLUSION</b>Losartan can alleviate ventilator-induced lung injury in mice and inhibit the expression of caveolin-1 and NOX4 and their interaction in the lungs.</p>

Effect of sesamin on pulmonary vascular remodeling in rats with monocrotaline-induced pulmonary hypertension / 中国中药杂志

<p><b>OBJECTIVE</b>To observe the effect of sesamin (Ses) on pulmonary vascular remodeling in rats with monocrotaline ( MCT)-induced pulmonary hypertension (PH).</p><p><b>METHOD</b>Totally 48 male Sprague-Dawley (SD) rats were fed adaptively for one week and then divided into the normal control group, the MCT group, the MCT +Ses (50 mg x kg(-1)) group and the MCT + Ses (100 mg x kg(-1)) group, with 12 rats in each group. The PH rat model was induced through the subcutaneous injection with MCT(60 mg x kg(-1)). After the administration for four weeks, efforts were made to measure the right ventricular systolic pressure( RVSP) and mean pulmonary artery pressure (mPAP) through right jugular vein catheterization, and isolate right ventricle( RV) and left ventricle( LV) +septum (S) and measure their length to calculate RV/ ( LV + S) and ratio of RV to tibial length. Pathologic changes in arterioles were observed by HE staining. Masson's trichrome stain was used to demonstrate changes in collagen deposition of arterioles. The alpha-smooth muscle actin (alpha-SMA) expression in pulmonary arteries was measured by immunohistochemisty. The total antioxidative capacity (T-AOC) and malondialdehyde (MDA) content in pulmonary arteries were determined by the colorimetric method. The protein expressions of collagen I, NOX2 and NOX4 were analyzed by Real-time PCR and Western blot.</p><p><b>RESULT</b>After the administration for 4 weeks, Ses could attenuate RVSP and mPAP induced by MCT, RV/ (LV + S) and ratio of RV to Tibial length, alpha-SMA and collagen I expressions and remodeling of pulmonary vessels and right ventricle. Meanwhile, Ses could obviously inhibit the expressions of NOX2, NOX4 and MDA content and increase T-AOC.</p><p><b>CONCLUSION</b>Sesamin could ameliorate pulmonary vascular remodeling induced by monocrotaline in PH rats. Its mechanism may be related to expressions of NOX2 and NOX4 expression and reduction in oxidative stress injury.</p>

Panax notoginseng saponins inhibits atherosclerotic plaque angiogenesis by down-regulating vascular endothelial growth factor and nicotinamide adenine dinucleotide phosphate oxidase subunit 4 expression / 中国结合医学杂志

<p><b>OBJECTIVE</b>To investigate the mechanism of Panax notoginseng saponins (PNS), an effective component extracted from Panax notoginseng, on atherosclerotic plaque angiogenesis in atherosclerosis-prone apolipoprotein E-knockout (ApoE-KO) mice fed with high-fat, high-cholesterol diet.</p><p><b>METHODS</b>Twenty ApoE-KO mice were divided into two groups, the model group and the PNS group. Ten normal C57BL/6J mice were used as a control group. PNS (60 mg/kg) was orally administered daily for 12 weeks in the PNS group. The ratio of plaque area to vessel area was examined by histological staining. The tissue sample of aortic root was used to detect the CD34 and vascular endothelial growth factor (VEGF) expression areas by immunohistochemistry. The expression of VEGF and nicotinamide adenine dinucleotide phosphate oxidase subunit 4 (NOX4) were measured by reverse transcription polymerase chain reaction and Western blotting respectively.</p><p><b>RESULTS</b>After treatment with PNS, the plaque areas were decreased (P<0.05). CD34 expressing areas and VEGF expression areas in plaques were significantly decreased (P<0.05). Meanwhile, VEGF and NOX4 mRNA expression were decreased after treatment with PNS. VEGF and NOX4 protein expression were also decreased by about 72% and 63%, respectively (P<0.01).</p><p><b>CONCLUSION</b>PNS, which decreases VEGF and NOX4 expression, could alleviate plaque angiogenesis and attenuate atherosclerosis.</p>

Effect of chrysin on expression of NOX4 and NF-κB in right ventricle of monocrotaline-induced pulmonary arterial hypertension of rats / 药学学报

The aim of the present study is to investigate the protective effect of chrysin (5,7-dihydroxyflavone) on right ventricular remodeling in a rat model of monocrotaline-induced pulmonary arterial hypertension (PAH). PAH rats were induced by a single injection of monocrotaline (60 mg x kg(-1), sc) and were administered with chrysin (50 or 100 mg x kg(-1) x d(-1)) for 4 weeks. At the end of experiment, the right ventricular systolic pressure (RVSP) and mean pulmonary artery pressure (mPAP) were monitored via the right jugular vein catheterization into the right ventricle. Right ventricle (RV) to left ventricle (LV) + septum (S) and RV to tibial length were calculated. Right ventricular morphological change was observed by HE staining. Masson's trichrome stain was used to demonstrate collagen deposition. The total antioxidative capacity (T-AOC) and malondialdehyde (MDA) levels in right ventricle were determined according to the manufacturer's instructions. The expressions of collagen I, collagen III, NADPH oxidase 4 (NOX4) and nuclear factor-kappa B (NF-κB) were analyzed by immunohistochemisty, qPCR and (or) Western blot. The results showed that chrysin treatment for 4 weeks attenuated RVSP, mPAP and right ventricular remodeling index (RV/LV+S and RV/Tibial length) of PAH rats induced by monocrotaline. Furthermore, monocrotaline-induced right ventricular collagen accumulation and collagen I and collagen III expression were both significantly suppressed by chrysin. The expressions of NOX4, NF-κB and MDA contents were obviously decreased, while the T-AOC was significantly increased in right ventricule from PAH rats with chrysin treatment. These results suggest that chrysin ameliorates right ventricular remodeling of PAH induced by monocrotaline in rats through its down-regulating of NOX4 expression and antioxidant activity, and inhibiting NF-κB expression and collagen accumulation.

Effect of bile duct ligation and recanalization on rat hepatocyte epithelial-mesenchymal phenotype and NOX4 protein expression / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe epithelial-mesenchymal phenotypes and oxidative stress related protein expressions of the liver cells in a rat model of liver fibrosis induced by bile duct ligation and recanalization.</p><p><b>METHODS</b>Twenty-four male Wistar rats were randomized into 4 groups, including a sham-operated group, two bile duct ligation groups with ligation for 2 and 4 weeks, and a bile duct ligation group with a 2-week ligation followed by a 2-week recanalization. HE staining and Masson staining were used to assess liver fibrosis in the rats, and immunohistochemistry and Western blotting were employed to detect expressions of the epithelial and mesenchymal marker proteins and oxidative stress-related proteins.</p><p><b>RESULTS</b>Compared with the sham-operated group, the rats with bile duct ligation showed obvious liver fibrosis, which worsened as the ligation time extended, accompanied by significantly increased expression of α-SMA, collagen I, NOX(4) and vimetin and reduced E-cadherin expression. Compared with the rats with bile duct ligation for 4 weeks, the rats in bile duct ligation-recanalization group showed obviously lessened liver fibrosis, significantly lowered expressions of NOX(4) and mesenchymal cell maker proteins, and enhanced expressions of epithelial cell marker proteins.</p><p><b>CONCLUSION</b>Bile duct ligation up-regulates mesenchymal phenotype-related proteins and NOX(4) protein expression and down-regulates the expression of epithelial phenotype-related proteins, and these changes can be reversed by subsequent bile duct recanalization.</p>

Relationship between expression of endothelial nitric oxide synthase and NADPH oxidase in lungs of mice exposed to chronic hypoxia / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To explore the relationship between the expression of endothelial nitric oxide synthase (eNOS) and NADPH oxidase (NOX) in the lungs of mice treated by chronic hypoxic exposure.</p><p><b>METHODS</b>Thirty male wild-type (WT) C57Bl/6 mice and thirty male eNOS-knockout (KO) C57BL/6 mice were randomly divided into normoxic groups (exposed to normoxia for 7 days or 21 days), hypoxic groups (exposed to 10% oxygen for 7 days or 21 days), and treatment groups (exposed to 10% oxygen and orally administrated 10 mmol/L 4-hydroxy TEMPO in drinking water for 7 days or 21 days) (n=6 in each group). The remodeling of the small pulmonary arteries was evaluated by the percentage of media wall thickness (MT%). The weight ratio of right ventricle to left ventricle plus septum (RV/[LV+S]) was calculated to evaluate the hypertrophy of right ventricle. Real-time PCR was used to measure the mRNA expression of NOX2, NOX4, and eNOS in mouse lungs. ELISA was used to determine the concentration of reactive oxygen species (ROS) in mouse lungs.</p><p><b>RESULTS</b>In WT mice and KO mice, the hypoxic groups had significantly increased pulmonary vascular remodeling and RV/[LV+S] compared with the normoxic and treatment groups (P<0.05), but there were no significant differences between the normoxic and treatment groups (P>0.05). In WT mice, the hypoxic and treatment groups had significantly lower ROS concentrations than the normoxic group (P<0.05), but there were no significant differences between the hypoxic and treatment groups (P>0.05). In WT mice, the mRNA expression of eNOS, NOX2, and NOX4 was significantly higher in the hypoxic group than in the normoxic group (P<0.05), and 4-hydroxy TEMPO reversed their over-expression. In the normoxic group, the KO mice had significantly higher NOX2 and NOX4 mRNA expression than the WT mice (P<0.05); in KO mice, the hypoxic group showed no significant changes in NOX4 mRNA expression (P>0.05), but had significantly reduced NOX2 mRNA expression (P<0.05), as compared with the normoxic group; the treatment group had reduced expression of NOX2 mRNA expression and increased NOX4 mRNA expression (P<0.05), as compared with the hypoxic group.</p><p><b>CONCLUSIONS</b>eNOS plays a key role in the regulation of expression of NOX2 and NOX4 in the lungs exposed to hypoxia. It suggests that NOX and eNOS may physically interact with one another in pulmonary vascular remodeling induced by chronic hypoxia.</p>

Catalpol protect diabetic vascular endothelial function by inhibiting NADPH oxidase / 中国中药杂志

The aim of the present study was to evaluate the protective effect of catalpol on vascular endothelial function in STZ-induced type 2 diabetes mellitus (T2DM) rats. 40 high-fat diet with STZ-induced diabetes rats were randomly divided into model group, catalpol low-dose, middle-dose and high-dose group (10, 50, 100 mg x kg(-1) x d(-1)), 10 normal Wistar rats were used as the normal group. The normal and model groups were given an equivalent amount of saline. All reagents were administered by oral gavage for 6 weeks. After 6 weeks, blood glucose and lipids were detected by an automatic biochemical analyzer. The endothelium-dependent vasodilation response of thoracic aortar was detected. The pathological changes of the thoracic aorta were observed by HE staining. Ser- um nitric oxide (NO), 8-iso prostaglandin F2α (8-iso-PGF2α) and superoxide dismutase (SOD) were detected by ELISA. Reactive oxygen species (ROS) level of thoracic aorta was detected by fluorescence method. The expression of Nox4 and p22phox mRNA and protein in aortic tissue were detected by RT-PCR and Western-blot respectively. After catalpol treatment, endothelial damage of thoracic aorta was attenuated significantly; ROS level of thoracic aorta and serum level of 8-iso-PGF2α were decreased significantly; serum NO and SOD levels were remarkably elevated; expression of Nox4, p22phox mRNA and protein in thoracic aorta were significantly reduced (P < 0.05). Therefore, catalpol has protective effect on endothelial of T2DM, its mechanism may be associated with the down-regulation of Nox4 and p22phox expression, inhibiting oxidative stress reaction response.

Effects of rutaecarpine on right ventriclar remodeling in rats with monocrotaline-induced pulmonary hypertension / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To investigate the protective effects of rutaecarpine (Rut) on right ventricular remodeling in rats with monocrotaline-induced pulmonary hypertension (PH).</p><p><b>METHOD</b>Forty-eight SD rats were fed adaptively for 1 week and then were randomly divided into the following 4 groups (n = 12): normal control group, monocrotaline (MCT) treatment group, MCT treatment with Rut (20 mg/kg)group and MCT treatment with Rut (40 mg/kg) group. PH rats were induced by a single injection of monocrotaline (60 mg/kg, sc) and were administered with Rut (20 or 40 mg/kg/d) for 4 weeks. At the end of experiment, the right ventricular systolic pressure (RVSP) and mean pulmonary artery pressure (mPAP) were monitored via the right jugular vein catheterization into the right ventricle. The ratio of right ventricle (RV) to left ventricle (LV) + septum (S) and the ratio of RV to tibial length were calculated. Right ventricular morphological changes were deserved by HE staining. Masson's trichrome staining was used to display collagen deposition. The total antioxidative capacity (T-AOC) and malondialdehyde (MDA) levels in right ventricle were determined according to the manufacturer's instructions. mRNA and protein expression levels of NOX4, collagen I and collagen III were analyzed by immunohistochemisty, real-time PCR and Western blot.</p><p><b>RESULTS</b>The results showed that Rut treatment for 4 weeks attenuated RVSP, mPAP and right ventricular remodeling index (RV/LV + S and RV/Tibial length) of PH rats induced by monocrotaline. Furthermore, the right ventricular collagen deposition and collagen I and collagen I expression induced by MCT were both significantly suppressed by Rut. The expression levels of NOX4 and MDA were obviously decreased, while the T-AOC was significantly increased in right ventricular from PH rats treated with Rut.</p><p><b>CONCLUSION</b>These results suggested that Rut ameliorates the right ventricular remodeling in rats with PH induced by MCT through down-regulating of NOX4 expression and collagen accumulation.</p>

Effect of sequoyitol on expression of NOX4 and eNOS induced with glucose in human umbilical vein endothelial cells / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To investigate the protective effect and mechanism of sequoyitol (Sep) on high glucose-induced human umbilical vein endothelial cells (HUVECs) injury.</p><p><b>METHODS</b>HUVECs were cultured with high glucose (30 mmol/L) in the presence or absence of sequoyitol (0.1, 1 and 10 micromol/L) for 24 h. Cell proliferation was measured by BrdU marking and cell cycle was detected by flow cytometry. 2', 7'-dichlorofluorescein diacetate was used to evaluate intracellular reactive oxygen species (ROS) levels. The NO, malonydialdehyde (MDA) and H2O2 levels were determined by colorimetric method according to the manufacturer's instructions. The expression of endothelial nitric oxide synthase (eNOS) and NADPH oxidase 4 (NOX4) were measured by real-time PCR and Western blot.</p><p><b>RESULTS</b>In the present study, we found that sequoyitol pretreatment for 1 h significantly decreased cell injury, promoted cell proliferation. Meanwhile sequoyitol significantly down-regulated NOX4 expression and decreased the level of ROS, MDA and H2O2 and obviously increased NO levels and up-regulated eNOS expression.</p><p><b>CONCLUSION</b>Sequoyitol alleviates high glucose-induced cell injuries in HUVECs via inhibiting oxidative stress and up-regulating eNOS expression.</p>

Effect of sequoyitol on expression of NOX4 and eNOS in aortas of type 2 diabetic rats / 药学学报

The aim of the present study is to investigate the effects of sequoyitol (Seq) on expression of eNOS and NOX4 in aortas of type 2 diabetic rats. Type 2 diabetic rats induced by high fat and high sugar diet and low dose of streptozotocin (STZ, 35 mg x kg(-1)) and were administered Seq (12.5, 25 and 50 mg x kg(-1) x d(-1)) for 6 weeks. The fasting blood glucose (FBG) and body weight were tested. Acetylcholine (Ach) induced endothelium-dependent relaxation and sodium nitroprusside (SNP) induced endothelium-independent relaxation were measured in aortas for estimating endothelial function. Aortic morphological change was observed with HE staining. The level of serum insulin was measured by radioimmunoassay. The total antioxidative capacity (T-AOC), malondialdehyde (MDA) and NO levels in aortas were determined according to the manufacturer's instructions. In addition, the expressions of eNOS and NOX4 in aortas were measured by immunohistochemisty, real-time PCR or Western blotting. The results showed that Seq significantly decreased FBG and insulin resistance, and improved aortic endothelium-dependent vasorelaxation function. The expressions of NOX4 and MDA content were obviously decreased, while the expression of eNOS, the levels of NO and T-AOC increased significantly in aortas of diabetic rats with Seq treatment. In conclusion, Seq protects against aortic endothelial dysfunction of type 2 diabetic rats through down-regulating expression of NOX4 and up-regulating eNOS expression.

Oxidative stress and calcium/calmodulin-dependent protein kinase II contribute to the development of sustained β adrenergic receptor-stimulated cardiac hypertrophy in rats / 生理学报

Sustained activation of β adrenergic receptor (βAR) leads to pathologic cardiac hypertrophy. However, the related mechanisms still remain unclear. In this study, we observe how N-acetylcysteine (NAC) affects the oxidative stress and calcium/calmodulin-dependent protein kinase II (CaMKII) expression in heart of isoproterenol (ISO)-stimulated rats, and investigate whether oxidative stress and CaMKII contribute to the development of sustained βAR-stimulated cardiac hypertrophy. Healthy male Wistar rats were randomly separated into 4 groups: control (CTRL), ISO-treated (ISO), control with NAC supplement (CTRL+NAC) and ISO-treated with NAC supplement (ISO+NAC) groups (6 rats in each group). Systolic blood pressure (SBP) was measured in awake rats with the tail-cuff method every week for two weeks. Heart weight/body weight ratio (HW/BW) and HE staining were used for the detection of myocardial hypertrophy. Myocardial mitochondrial reactive oxygen species (ROS) levels were measured by DCF fluorometry. The expressions of activated-CaMKII (p-CaMKII/CaMKII) and NADPH oxidase 4 (NOX(4)) were determined by Western blot analysis. The results showed that ISO-treated (i.p., daily 3 mg/kg, 2 weeks) rats developed an obvious cardiac hypertrophy as expressed by increases of HW/BW and myocyte cross-section area. Cardiac mitochondrial ROS level was significantly enhanced in ISO group as compared to CTRL group (P < 0.05). The expressions of NOX(4) and p-CaMKII in ISO group were also up-regulated as compared to CTRL group (1.4 and 1.6 times of CTRL, respectively, P < 0.05). NAC supplement significantly suppressed the hypertrophic development of heart in ISO-stimulated rats. The cardiac mitochondrial ROS level showed a significant decrease in rats of ISO+NAC group (P < 0.05 vs ISO). In accordance with this, ISO+NAC group rats also showed marked reductions in the expressions of NOX(4) and p-CaMKII/CaMKII compared to ISO group rats (P < 0.05). There were no significant differences of the detected indices between the rats from CTRL+NAC and CTRL groups. SBP showed no differences among four groups. These results suggest that both oxidative stress and CaMKII play important roles in sustained βAR-stimulated cardiac hypertrophy. NAC may suppress ISO-induced cardiac hypertrophy by down-regulating the expression of activated-CaMKII, and by reducing the level of oxidative stress originated from mitochondria and NADPH oxidase pathways.

Aldosterone antagonist inhibits fibrosis-induced NOX4 protein expression in hepatic cells and tissues of rats / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To investigate the inhibitory potential of aldosterone antagonist on NOX4 protein expression in hepatic fibrosis by using a rat model of carbon tetrachloride (CCl4)-induced hepatotoxicity.</p><p><b>METHODS</b>Twenty-four male Wistar rats were randomly divided into three equal groups: fibrosis model group (receiving three subcutaneous injections per week of 2.5 ml/kg 40% CCl4); spironolactone (Sp)-treated fibrosis model group (receiving CCl4 regimen plus three injections per day of 20 mg/kg Sp in olive oil); negative-treatment fibrosis model group (receiving CCl4 regimen plus three injections per day of olive oil alone). Unmanipulated rats (receiving no CCl4 and no supplemental treatments) served as normal controls. After 4 weeks, liver histology was carried out to assess cytotoxicity (by hematoxylin-eosin staining), fibrosis (by Masson staining and METAVIR scoring), and NOX4 protein expression (by immunohistochemistry). In addition, in vitro analyses of immortalized rat hepatic stellate cells, HSC-T6, were performed to evaluate dose-response (10-9, 10-7 and 10-5 mol/L) and time-response (6, 12 and 24 h) of aldosterone agonist (Ald) and an aldosterone antagonist, eplerenone (EPLE). Effects on NOX4 protein expression were evaluated by western blotting.</p><p><b>RESULTS</b>The fibrosis model group showed significantly more fibrosis than the normal control group (16.060 +/- 0.300 vs. 2.471 +/- 0.160, P = 0.000]; however, the Sp-treated fibrosis model group showed significantly less CCl4-induced fibrosis (5.761 +/- 0.152 vs. model: 16.060 +/- 0.300, P = 0.000). The fibrosis model group also showed significantly higher NOX4 protein expression in liver tissues than the normal control group (7.231 +/- 0.211 vs. 1.350 +/- 0.252, P = 0.000), and the Sp-treated fibrosis model tissues showed significantly less CCl4-induced up-regulated NOX4 protein expression (4.270 +/- 0.242 vs. model: 7.231 +/- 0.211, P = 0.000]. Ald induced up-regulated NOX4 protein expression in HSC-T6 cells in dose- and concentration-dependent manners, with the peak expression being induced by the 10-5 mol/L concentration and 24 h exposure. The Ald-treated cells expressed significantly more NOX4 protein than the untreated control cells (0.710 +/- 0.011 vs. 0.316 +/- 0.015, P = 0.000]. and the EPLE-treated cells showed significantly less Ald-induced up-regulated NOX4 expression (0.615 +/- 0.014 vs. 0.710 +/- 0.011, P = 0.000].</p><p><b>CONCLUSION</b>Aldosterone antagonists inhibit the fibrosis-induced NOX4 protein expression in rat hepatic cells.</p>

The role of JNK in apoptosis of renal tubular epithelial cells in diabetic rats with fluctuant high blood glucose / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To explore the signal transduction mechanisms of apoptosis in renal tubular epithelial cells in diabetic rats with fluctuant high blood glucose.</p><p><b>METHODS</b>Healthy SD rats were randomly divided into 3 groups: normal control group (A), stable high blood glucose group (B) and fluctuant high blood glucose group (C). Diabetic rats were induced by intraperitoneal injection of streptozotocin (STZ, 65 mg/kg), and the fluctuant high blood glucose animal model was induced by intraperitoneal injection of ordinary insulin and glucose at different time point every day. The superoxide dismutase (SOD) activity and the content of malonaldehyde (MDA) in renal tissue homogenate were detected with colorimetry. The protein expression of Nox4 and JNK were examined by immunohistochemistry and Western blot. Apoptosis was assessed by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL).</p><p><b>RESULTS</b>After 12 experimental weeks, significantly increased cell apoptosis, up-regulation of Nox4 and P-JNK expression in renal tubular epithelial cells were observed in B and C groups compared with those in A group. The MDA content increased and SOD activity decreased in renal tissue in B and C groups. Above effects were more obviously shown in C group.</p><p><b>CONCLUSION</b>Fluctuant high blood glucose induced more apoptosis of renal tubular epithelial cell than stable high blood glucose in diabetic kidney, which might be related to the activation of JNK signal transduction pathway.</p>

Protective effect of epalrestat against high glucose-induced endothelial cell injuries / 南方医科大学学报

<p><b>OBJECTIVE</b>To study the protective effect of epalrestat against endothelial cell injuries induced by high glucose.</p><p><b>METHODS</b>Human umbilical vein endothelial cells were pretreated with epalrestat (0.1 µmol/L) for 30 min followed by exposure to high glucose for 8 h. NO concentration in the cell culture supernatant was assayed using chemiluminescence method following the exposure. Real-time PCR and Western blotting were used to detect eNOS mRNA and protein expression levels and the protein expressions of AR gene (the target gene of epalrestat) and NOX4 (the upstream gene of NO).</p><p><b>RESULTS</b>Compared with mannitol treatment, an 8-h exposure to high glucose caused significantly decreased NO levels and eNOS mRNA and protein expression in the vascular endothelial cells (P<0.05). Pretreatment with epalrestat prior to high glucose exposure resulted in elevated eNOS mRNA and protein expression levels and NO up-regulation in the cell culture as compared with the glucose exposure alone group (P<0.05), causing also decreased expression of AR and NOX4 in the cells.</p><p><b>CONCLUSIONS</b>High glucose can induce endothelial cell damage characterized by a lowered level of NO secretion. Epalrestat can protect the endothelial cells against high glucose-induced injury by inhibiting the expression of AR and NOX4.</p>