AIM: To determine the effects of allopurinol, an inhibitor of xanthine oxidase, and apocynin, an inhibitor of NADPH oxidase, on oxidant stress and liver injury caused by hepatic ischemia/reperfusion (I/R) procedure in...AIM: To determine the effects of allopurinol, an inhibitor of xanthine oxidase, and apocynin, an inhibitor of NADPH oxidase, on oxidant stress and liver injury caused by hepatic ischemia/reperfusion (I/R) procedure in mice. METHODS: Mice were pretreated with a xanthine oxidase inhibitor, allopurinol, or NADPH oxidase (NOX) inhibitor, apocynin before the hepatic I/R procedure. Then treated or untreated mice underwent the hepatic I/R procedure. The effects on hepatic injury and superoxide anions were determined after starting reperfusion. RESULTS: A standard warm hepatic I/R procedure led to a marked increase in superoxide anion production as indicated by a superoxide anion tracer, MCLA. At the same time, the procedure caused profound acute liver injury, as indicated by elevated serum alanine aminotransferase and tumor necrosis factor-α levels, reduced liver glutathione levels and elevated malondialdehyde contents, as well as a high apoptotic cell count. All these changes were reversed by the use of apocynin or allopurinol prior to the hepatic I/R procedure. CONCLUSION: Allopurinol and apocynin exerted protective effects on hepatic ischemia/reperfusion injury. The protection is associated with blocking the generationof superoxide anions during the hepatic I/R procedure by inhibiting xanthine oxidase and NADPH oxidase activity.展开更多
Increased reactive oxygen species by the activation of NADPH oxidase（NOX） contributes to the development of diabetic complications.Apocynin,a NOX inhibitor,increases sciatic nerve conductance and blood flow in diabe...Increased reactive oxygen species by the activation of NADPH oxidase（NOX） contributes to the development of diabetic complications.Apocynin,a NOX inhibitor,increases sciatic nerve conductance and blood flow in diabetic rats.We investigated potential protective effect of apocynin in rat diabetic neuropathy and its precise mechanism of action at molecular level.Rat models of streptozotocin-induced diabetes were treated with apocynin（30 and 100 mg/kg per day,intragastrically） for 4 weeks.Mechanical hyperalgesia and allodynia were determined weekly using analgesimeter and dynamic plantar aesthesiometer.Western blot analysis and histochemistry/immunohistochemistry were performed in the lumbar spinal cord and sciatic nerve respectively.Streptozotocin injection reduced pain threshold in analgesimeter,but not in aesthesiometer.Apocynin treatment increased pain threshold dose-dependently.Western blot analysis showed an increase in catalase and NOX-p47 phox protein expression in the spinal cord.However,protein expressions of neuronal and inducible nitric oxide synthase（n NOS,i NOS）,superoxide dismutase,glutathion peroxidase,nitrotyrosine,tumor necrosis factor-α,interleukin-6,interleukin-1β,aldose reductase,cyclooxygenase-2 or MAC-1（marker for increased microgliosis） in the spinal cord remained unchanged.Western blot analysis results also demonstrated that apocynin decreased NOX-p47 phox expression at both doses and catalase expression at 100 mg/kg per day.Histochemistry of diabetic sciatic nerve revealed marked degeneration.n NOS and i NOS immunoreactivities were increased,while S-100 immunoreactivity（Schwann cell marker） was decreased in sciatic nerve.Apocynin treatment reversed these changes dose-dependently.In conclusion,decreased pain threshold of diabetic rats was accompanied by increased NOX and catalase expression in the spinal cord and increased degeneration in the sciatic nerve characterized by increased NOS expression and Schwann cell loss.Apocynin treatment attenuates neuropathic pain by de展开更多
AIM: To investigate the role of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase in colon epithelial cells in the pathogenesis of acute and chronic colon inflammation in a mouse model of dextran sulphate so...AIM: To investigate the role of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase in colon epithelial cells in the pathogenesis of acute and chronic colon inflammation in a mouse model of dextran sulphate sodium (DSS)-induced colitis.展开更多
The effects of nicotinamide adenine dinucleotide phosphate （NADPH） oxidase inhibitor apocynin on the enhanced hypoxia induced factor-let （HIF-lct） and endothelin-1 （ET-1） expression, elevated systolic blood pres...The effects of nicotinamide adenine dinucleotide phosphate （NADPH） oxidase inhibitor apocynin on the enhanced hypoxia induced factor-let （HIF-lct） and endothelin-1 （ET-1） expression, elevated systolic blood pressure under chronic intermittent hypoxia （CIH） condition and its action mechanism were investigated. Thirty healthy 8-week old Sprague-Dawley （SD） male rats were randomly divided into three groups （n=10 each）： sham group, CIH group, and apocynin-treated CIH group. Tail artery systolic blood pressure was measured by tail-cuff method. Real-time fluorescence quantitative polymerase chain reaction （PCR） was used to detect the mRNA expression of HIF-lu and ET-1 in the carotid body, and the HIF-1a protein expression was examined by using Western blotting. The levels of malondialdehyde （MDA） and superoxide dismutase （SOD） were determined by using colorimetric method. In addition, the plasma ET-1 and HIF-1a levels were measured by using enzyme-linked immunosorbent assay. It was found that CIH exposure was associated with increased MDA levels, and apo- cynin-treated CIH animals showed reduction in MDA levels. Apocynin treatment prevented CIH-induced hypertension as well as CIH-induced decrease in SOD. The increases of HIF-1a and ET-1 mRNA along with HIF-la protein expression in the carotid body, and elevated circulating HIF-1a and ET-1 levels were observed in CIH-exposed animals. Treatment with apocynin significantly decreased the ET-1 mRNA, HIF-lct protein expression and circulating HIF-la level in CIH-exposed animals, and there was no statistically significant difference in the HIF-lu mRNA expression between CIH group and apo- cynin-treated group. These results indicated that apocynin alleviated CIH-induced hypertension by inhibiting NADPH oxidase, further leading to the reduced vasoconstrictor ET-1 level and oxidative stress. HIF-1a/ET-1 system signal pathway may interact with CIH-induced NADPH oxidase-dependent oxidative stress. Inhibition of NADPH oxidase activity may hopef展开更多
基金The National Institute of Diabetes, Digestive and Kidney Diseases (NIDDK), DK069939 the Technology Transfer Grant (TTG) by UC Davis Medical Center to Wu J
文摘AIM: To determine the effects of allopurinol, an inhibitor of xanthine oxidase, and apocynin, an inhibitor of NADPH oxidase, on oxidant stress and liver injury caused by hepatic ischemia/reperfusion (I/R) procedure in mice. METHODS: Mice were pretreated with a xanthine oxidase inhibitor, allopurinol, or NADPH oxidase (NOX) inhibitor, apocynin before the hepatic I/R procedure. Then treated or untreated mice underwent the hepatic I/R procedure. The effects on hepatic injury and superoxide anions were determined after starting reperfusion. RESULTS: A standard warm hepatic I/R procedure led to a marked increase in superoxide anion production as indicated by a superoxide anion tracer, MCLA. At the same time, the procedure caused profound acute liver injury, as indicated by elevated serum alanine aminotransferase and tumor necrosis factor-α levels, reduced liver glutathione levels and elevated malondialdehyde contents, as well as a high apoptotic cell count. All these changes were reversed by the use of apocynin or allopurinol prior to the hepatic I/R procedure. CONCLUSION: Allopurinol and apocynin exerted protective effects on hepatic ischemia/reperfusion injury. The protection is associated with blocking the generationof superoxide anions during the hepatic I/R procedure by inhibiting xanthine oxidase and NADPH oxidase activity.
基金supported by the Research Fund of Ege University(Project No.2010-TIP-076)
文摘Increased reactive oxygen species by the activation of NADPH oxidase（NOX） contributes to the development of diabetic complications.Apocynin,a NOX inhibitor,increases sciatic nerve conductance and blood flow in diabetic rats.We investigated potential protective effect of apocynin in rat diabetic neuropathy and its precise mechanism of action at molecular level.Rat models of streptozotocin-induced diabetes were treated with apocynin（30 and 100 mg/kg per day,intragastrically） for 4 weeks.Mechanical hyperalgesia and allodynia were determined weekly using analgesimeter and dynamic plantar aesthesiometer.Western blot analysis and histochemistry/immunohistochemistry were performed in the lumbar spinal cord and sciatic nerve respectively.Streptozotocin injection reduced pain threshold in analgesimeter,but not in aesthesiometer.Apocynin treatment increased pain threshold dose-dependently.Western blot analysis showed an increase in catalase and NOX-p47 phox protein expression in the spinal cord.However,protein expressions of neuronal and inducible nitric oxide synthase（n NOS,i NOS）,superoxide dismutase,glutathion peroxidase,nitrotyrosine,tumor necrosis factor-α,interleukin-6,interleukin-1β,aldose reductase,cyclooxygenase-2 or MAC-1（marker for increased microgliosis） in the spinal cord remained unchanged.Western blot analysis results also demonstrated that apocynin decreased NOX-p47 phox expression at both doses and catalase expression at 100 mg/kg per day.Histochemistry of diabetic sciatic nerve revealed marked degeneration.n NOS and i NOS immunoreactivities were increased,while S-100 immunoreactivity（Schwann cell marker） was decreased in sciatic nerve.Apocynin treatment reversed these changes dose-dependently.In conclusion,decreased pain threshold of diabetic rats was accompanied by increased NOX and catalase expression in the spinal cord and increased degeneration in the sciatic nerve characterized by increased NOS expression and Schwann cell loss.Apocynin treatment attenuates neuropathic pain by de
文摘AIM: To investigate the role of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase in colon epithelial cells in the pathogenesis of acute and chronic colon inflammation in a mouse model of dextran sulphate sodium (DSS)-induced colitis.
基金supported by the National Natural Science Foundation of China(No.81070067)
文摘The effects of nicotinamide adenine dinucleotide phosphate （NADPH） oxidase inhibitor apocynin on the enhanced hypoxia induced factor-let （HIF-lct） and endothelin-1 （ET-1） expression, elevated systolic blood pressure under chronic intermittent hypoxia （CIH） condition and its action mechanism were investigated. Thirty healthy 8-week old Sprague-Dawley （SD） male rats were randomly divided into three groups （n=10 each）： sham group, CIH group, and apocynin-treated CIH group. Tail artery systolic blood pressure was measured by tail-cuff method. Real-time fluorescence quantitative polymerase chain reaction （PCR） was used to detect the mRNA expression of HIF-lu and ET-1 in the carotid body, and the HIF-1a protein expression was examined by using Western blotting. The levels of malondialdehyde （MDA） and superoxide dismutase （SOD） were determined by using colorimetric method. In addition, the plasma ET-1 and HIF-1a levels were measured by using enzyme-linked immunosorbent assay. It was found that CIH exposure was associated with increased MDA levels, and apo- cynin-treated CIH animals showed reduction in MDA levels. Apocynin treatment prevented CIH-induced hypertension as well as CIH-induced decrease in SOD. The increases of HIF-1a and ET-1 mRNA along with HIF-la protein expression in the carotid body, and elevated circulating HIF-1a and ET-1 levels were observed in CIH-exposed animals. Treatment with apocynin significantly decreased the ET-1 mRNA, HIF-lct protein expression and circulating HIF-la level in CIH-exposed animals, and there was no statistically significant difference in the HIF-lu mRNA expression between CIH group and apo- cynin-treated group. These results indicated that apocynin alleviated CIH-induced hypertension by inhibiting NADPH oxidase, further leading to the reduced vasoconstrictor ET-1 level and oxidative stress. HIF-1a/ET-1 system signal pathway may interact with CIH-induced NADPH oxidase-dependent oxidative stress. Inhibition of NADPH oxidase activity may hopef
