Abstract
Lycium barbarum polysaccharide (LBP) has been shown to have hypoglycemic and antioxidative properties, although its mode of action is yet unknown. Because oxidative stress is implicated in the pathogenesis of diabetic nephropathy, we evaluated the protective effect of LBP-4, the major active component of Lycium barbarum, on the defensive antioxidative mechanism in kidneys in a streptozotocin-induced diabetic rat model. Moreover, we investigated the effects of LBP-4 on the activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) in isolated mesangial cells. The role of protein kinase C (PKC)-dependent and -independent pathways in LBP-4-reduced ERK1/2 was studied by bisindolylmaleimide (BIM) IV, an inhibitor of PKC. Diabetic rats treated with LBP-4 (10 mg/kg) for 8 weeks showed increased activity of antioxidant enzymes and increased scavenging of oxygen radicals, while the activity of PKC in the renal cortex was maintained at a physiological level. The decreased activation of ERK1/2 in mesangial cells, through the involvement of PKC, could explain the protective mechanism in kidneys of diabetic rats treated with LBP-4.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Antioxidants / administration & dosage
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Antioxidants / pharmacology
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Antioxidants / therapeutic use*
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Blood Glucose / analysis
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Blood Glucose / metabolism
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Blotting, Western
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Cell Membrane / drug effects
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Cell Membrane / enzymology
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Cell Membrane / metabolism
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Cells, Cultured
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Diabetes Mellitus, Experimental / complications*
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Diabetes Mellitus, Experimental / enzymology
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Diabetes Mellitus, Experimental / metabolism
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Diabetic Nephropathies / enzymology
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Diabetic Nephropathies / etiology
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Diabetic Nephropathies / metabolism
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Diabetic Nephropathies / prevention & control*
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Drugs, Chinese Herbal / administration & dosage
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Drugs, Chinese Herbal / pharmacology
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Drugs, Chinese Herbal / therapeutic use*
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Electrophoresis, Polyacrylamide Gel
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Kidney Cortex / drug effects*
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Kidney Cortex / metabolism
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Lipid Metabolism / drug effects
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Male
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Mesangial Cells / drug effects
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Mesangial Cells / enzymology
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Mesangial Cells / metabolism
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Mitogen-Activated Protein Kinase 1 / metabolism
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Mitogen-Activated Protein Kinase 3 / metabolism
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Protein Kinase C / metabolism
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Rats
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Rats, Wistar
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Streptozocin
Substances
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Antioxidants
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Blood Glucose
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Drugs, Chinese Herbal
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lycium barbarum polysaccharide
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Streptozocin
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Protein Kinase C
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Mitogen-Activated Protein Kinase 1
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Mitogen-Activated Protein Kinase 3