Korkmaz Gulcan G, Uzun Hafize, Cakatay Ufuk, Aydin Seval
Kirklareli University, School of Health, Kirklareli, Turkey.
Clin Invest Med. 2012 Dec 1;35(6):E370-7. doi: 10.25011/cim.v35i6.19209.
Melatonin (N-acetyl-5-methoxy-tryptamine) is synthesized mainly by the pineal gland and its antioxidant properties have been demonstrated both in short and long term studies. Our aim was to clarify the effects of hyperglycemia and to administer melatonin on lipid peroxidation, protein oxidation and oxidative DNA damage in rat.
Malondialdehyde (MDA), protein carbonyl (PCO) and total thiol (T-SH) levels were determined in plasma and liver tissue, glutathione (GSH) levels in erythrocyte and liver tissue, and 8-hydroxy-2-deoxyguanosine (8-OHdG) levels in plasma and liver. Thirty-eight male Wistar rats were divided into four groups: 1--injected with saline (n = 8), 2--injected with melatonin (n = 10), 3--injected with STZ (65 mg/kg, i.p.) (diabetic group) (n = 10) and 4--injected with melatonin (10 mg/kg/day, i.p.) and STZ (65 mg/kg, i.p.) (n = 10) for 8 weeks (diabetic+ melatonin group). Colorimetric methods were used to determine the level of the oxidative stress markers. 8-OhdGwas measured using ELISA.
MDA, PCO and 8-OHdG levels in the plasma and the liver homogenates of diabetic rats were higher than controls and were significantly reduced after melatonin treatment. T-SH and GSH levels in samples were markedly reduced in untreated diabetic rats compared with control rats; however, these parameters were increased in diabetic rats following melatonin treatment.
Our findings showed that melatonin administration partially ameliorated oxidative damage in liver injury in STZ-induced diabetic rats. The present study suggests that melatonin functions as a potent antioxidant agent in diabetes. Melatonin, a nutritional supplement, may be a good therapeutic option for diabetic patients.
褪黑素（N-乙酰-5-甲氧基色胺）主要由松果体合成，其抗氧化特性已在短期和长期研究中得到证实。我们的目的是阐明高血糖的影响，并给予褪黑素对大鼠脂质过氧化、蛋白质氧化和氧化性DNA损伤的作用。
测定血浆和肝组织中的丙二醛（MDA）、蛋白质羰基（PCO）和总巯基（T-SH）水平，红细胞和肝组织中的谷胱甘肽（GSH）水平，以及血浆和肝中的8-羟基-2-脱氧鸟苷（8-OHdG）水平。38只雄性Wistar大鼠分为四组：1组——注射生理盐水（n = 8），2组——注射褪黑素（n = 10），3组——注射链脲佐菌素（65 mg/kg，腹腔注射）（糖尿病组）（n = 10），4组——注射褪黑素（10 mg/kg/天，腹腔注射）和链脲佐菌素（65 mg/kg，腹腔注射）（n = 10），持续8周（糖尿病+褪黑素组）。采用比色法测定氧化应激标志物水平。使用酶联免疫吸附测定法测量8-OhdG。
糖尿病大鼠血浆和肝匀浆中的MDA、PCO和8-OHdG水平高于对照组，褪黑素治疗后显著降低。与对照大鼠相比，未治疗的糖尿病大鼠样本中的T-SH和GSH水平明显降低；然而，褪黑素治疗后糖尿病大鼠的这些参数有所增加。
我们的研究结果表明，给予褪黑素可部分改善链脲佐菌素诱导的糖尿病大鼠肝损伤中的氧化损伤。本研究表明，褪黑素在糖尿病中起强效抗氧化剂的作用。褪黑素作为一种营养补充剂，可能是糖尿病患者的良好治疗选择。
