Details

Autor(en) / Beteiligte

• MUSTATA, Georgian T
• ROSCA, Mariana
• LEDERER, Markus O
• BROWNLEE, Michael
• WEISS, Miriam F
• MONNIER, Vincent M
• BIEMEL, Klaus M
• REIHL, Oliver
• SMITH, Mark A
• VISWANATHAN, Ashwini
• STRAUCH, Christopher
• YUNPENG DU
• JIE TANG
• KERN, Timothy S

Titel

Paradoxical effects of green tea (Camellia sinensis) and antioxidant vitamins in diabetic rats: Improved retinopathy and renal mitochondrial defects but deterioration of collagen matrix glycoxidation and cross-linking

Ist Teil von

• Diabetes (New York, N.Y.), 2005-02, Vol.54 (2), p.517-526

Ort / Verlag

Alexandria, VA: American Diabetes Association

Erscheinungsjahr

2005

Quelle

Electronic Journals Library

Beschreibungen/Notizen

• We tested the hypothesis that green tea prevents diabetes-related tissue dysfunctions attributable to oxidation. Diabetic rats were treated daily with tap water, vitamins C and E, or fresh Japanese green tea extract. After 12 months, body weights were decreased, whereas glycated lysine in aorta, tendon, and plasma were increased by diabetes (P < 0.001) but unaffected by treatment. Erythrocyte glutathione and plasma hydroperoxides were improved by the vitamins (P < 0.05) and green tea (P < 0.001). Retinal superoxide production, acellular capillaries, and pericyte ghosts were increased by diabetes (P < 0.001) and improved by green tea and the vitamins (P variable). Lens crystallin fluorescence at 370/440 nm was ameliorated by green tea (P < 0.05) but not the vitamins. Marginal effects on nephropathy parameters were noted. However, suppressed renal mitochondrial NADH-linked ADP-dependent and dinitrophenol-dependent respiration and complex III activity were improved by green tea (P variable). Green tea also suppressed the methylglyoxal hydroimidazolone immunostaining of a 28-kDa mitochondrial protein. Surprising, glycoxidation in tendon, aorta, and plasma was either worsened or not significantly improved by the vitamins and green tea. Glucosepane cross-links were increased by diabetes (P < 0.001), and green tea worsened total cross-linking. In conclusion, green tea and antioxidant vitamins improved several diabetes-related cellular dysfunctions but worsened matrix glycoxidation in selected tissues, suggesting that antioxidant treatment tilts the balance from oxidative to carbonyl stress in the extracellular compartment.