Department of Pharmacology, Delhi Institute of Pharmaceutical Sciences and Research, University of Delhi, New Delhi, India.
Ophthalmic Res. 2012;47(2):103-8. doi: 10.1159/000330051. Epub 2011 Oct 12.
Our objective was to investigate the effect of green tea (GT) on diabetes-induced retinal oxidative stress and proinflammatory parameters in rats.
Treatment (200 mg/kg body weight) was carried out for a period of 16 weeks in streptozotocin-induced diabetic rats and was evaluated for hypoglycemic, antioxidant [reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT)] and anti-inflammatory [tumor necrosis factor (TNF) α, vascular endothelial growth factor (VEGF)] activity. Histological changes were evaluated by transmission electron microscopy.
Retinal GSH levels were 1.5-fold lower in diabetic rats as compared to normal rats (p < 0.05). However, in GT-treated rats, retinal GSH levels were restored close to those of the normal group. The antioxidant enzymes SOD and CAT showed a more than 2-fold decrease in activity in diabetic retinae as compared to normal retinae (p < 0.05). Both SOD and CAT enzymatic activities were restored close to normal in the GT-treated group. Expression of proinflammatory parameters (TNF-α and VEGF) was significantly inhibited in GT-treated retinae as compared to diabetic retinae (p < 0.05). Moreover, GT treatment prevented retinal capillary basement membrane thickness.
The beneficial effects of GT suggest its potential role in the prevention and treatment of diabetic retinopathy in human subjects.
本研究旨在探讨绿茶（GT）对糖尿病大鼠视网膜氧化应激和促炎参数的影响。
采用链脲佐菌素诱导的糖尿病大鼠模型，给予 GT（200mg/kg 体重）治疗 16 周，评估其降血糖、抗氧化[还原型谷胱甘肽（GSH）、超氧化物歧化酶（SOD）和过氧化氢酶（CAT）]和抗炎[肿瘤坏死因子（TNF）α、血管内皮生长因子（VEGF）]作用。采用透射电镜评估组织学变化。
与正常大鼠相比，糖尿病大鼠视网膜 GSH 水平降低了 1.5 倍（p<0.05）。然而，在 GT 治疗组，视网膜 GSH 水平恢复到接近正常组的水平。与正常视网膜相比，糖尿病视网膜中抗氧化酶 SOD 和 CAT 的活性降低了 2 倍以上（p<0.05）。在 GT 治疗组，SOD 和 CAT 的酶活性均恢复到接近正常水平。与糖尿病视网膜相比，GT 治疗组促炎参数（TNF-α和 VEGF）的表达显著受到抑制（p<0.05）。此外，GT 治疗可预防视网膜毛细血管基底膜厚度增加。
GT 的有益作用表明其在预防和治疗人类糖尿病视网膜病变方面具有潜在的作用。
