Department of Pediatrics, School of Medicine, Texas Tech University Health Sciences Center, Amarillo, TX 79106, USA.
Nutr Res. 2012 May;32(5):347-56. doi: 10.1016/j.nutres.2012.03.015. Epub 2012 May 15.
Diabetic nephropathy is a complication of diabetes mellitus leading to end-stage renal disease. Oxidative stress and inflammation play a major role in the pathogenesis of diabetic nephropathy. Green tea, known for its antioxidant and anti-inflammatory properties, has been shown to be renoprotective. We hypothesized that (+)-catechin (CTN), a component of green tea, is responsible for the renoprotection. Our investigation of the therapeutic potential of CTN in streptozotocin-induced diabetic rats demonstrated for the first time that the effects of CTN treatment were comparable with the effects of an angiotensin-converting enzyme inhibitor (ACEi) enalapril for the treatment of albumin excretion. After 12 weeks of CTN treatment with 35 mg/d in the drinking water, urinary albumin excretion and plasma creatinine concentrations in all the diabetic treatment groups were reduced, compared with the diabetic group with no treatment. Urine creatinine and creatinine clearance were higher in diabetic groups treated with CTN and ACEi compared with the diabetic group with no treatment. Endothelin 1, lipid peroxidation, concentration of alanine transferase enzyme, and expression of fibronectin were lower in all the treatment groups compared with the diabetic group with no treatment. Concentrations of free thiols were higher in the CTN-treated group compared with the diabetic rats with no treatment. Our findings suggest that CTN has renoprotective properties comparable with ACEi, and coadministration of CTN and enalapril might be useful in reducing albumin excretion as well as improving endothelial function. (+)-Catechin might be successfully used in the future for clinical situations where ACEi is poorly tolerated or contraindicated.
糖尿病肾病是糖尿病导致终末期肾病的一种并发症。氧化应激和炎症在糖尿病肾病的发病机制中起主要作用。绿茶以其抗氧化和抗炎特性而闻名，已被证明具有肾脏保护作用。我们假设（+）-儿茶素（CTN），绿茶的一种成分，是肾脏保护的原因。我们首次调查了 CTN 治疗链脲佐菌素诱导的糖尿病大鼠的治疗潜力，结果表明 CTN 治疗的效果可与血管紧张素转换酶抑制剂（ACEi）依那普利治疗白蛋白排泄相媲美。在饮用水中用 35mg/d 的 CTN 治疗 12 周后，与未治疗的糖尿病组相比，所有糖尿病治疗组的尿白蛋白排泄和血浆肌酐浓度均降低。与未治疗的糖尿病组相比，用 CTN 和 ACEi 治疗的糖尿病组的尿肌酐和肌酐清除率更高。与未治疗的糖尿病组相比，所有治疗组的内皮素 1、脂质过氧化、丙氨酸转移酶浓度和纤维连接蛋白表达均降低。与未治疗的糖尿病大鼠相比，CTN 治疗组的游离巯基浓度更高。我们的发现表明，CTN 具有与 ACEi 相当的肾脏保护特性，联合使用 CTN 和依那普利可能有助于减少白蛋白排泄并改善内皮功能。（+）-儿茶素可能在未来在 ACEi 耐受性差或禁忌的临床情况下成功使用。
