2型糖尿病患者血清褪黑素水平及分泌节律的改变与氧化应激的关系

目的观察2型糖尿病(T2DM)患者血清褪黑素(MT)水平及节律变化与氧化应激的关系。方法选择T2DM患者32例(DM组)和正常对照16例(NC组)作为研究对象。DM组又分为合并大血管病变(MV)和无大血管病变(NMV)两个亚组。受试者于02:00(t2)和08:00(t8)抽血测定血清MT、超氧化物歧化酶(SOD)、一氧化氮(NO)的水平,以t2和t8时间点的比值表示其昼夜节律的变化。结果①与NC组比较,DM组的血清MTt2水平、MTt2/t8的比值均显著降低(P<0.01)。DM组两亚组比较,MV组的血清MTt2水平、MTt2/t8的比值显著低于NMV组(P<0.01)。②DM组的血清SODt2、SODt8的活性显著低于NC组(P<0.01),NOt2、NOt8含量显著高于NC组(P<0.05)。与NMV组比较,MVC组的血清SODt2、SODt8活性显著降低(P<0.01),血清NOt2、NOt8含量显著升高(P<0.05)。③多元线性回归分析显示,MTt2与患者的病程、HbA1c、NOt2呈负相关(P<0.05),与SODt2呈正相关(P<0.01);而MTt8仅与NOt8呈负相关(P<0.05)。结论 T2DM患者存在MT夜间血清水平降低及昼夜分泌节律紊乱,并与机体氧化应激增强有相关性,这可能参与了糖尿病大血管并发症的发生与发展。

Relationship between the alteration of the serum melatonin level and its secretion rhythm and oxidative stress in type 2 diabetics

Objective To investigate the relationship between the alteration of the serum melatonin(MT)level and its secretion rhythm and oxidative stress in patients with type 2 diabetes.Methods 32 patients with type 2 diabetic mellitus(DM group) and 16 cases of normal controls(NC group)were selected as study subjects.The DM group was further divided into the macrovascular subgroup(MV) and the nonmacrovascular subgroup(NMV).The levels of melatonin(MT),superoxide dismutase(SOD)and nitric oxide(NO)in the serum were measured at 02:00(t2)and 08:00(t8) respectively,and the t2 to t8 ratio of every above index was used to indicate its circadian rhythm change.Results ① The serum MTt2 level and the ratio of MTt2/t8 were significantly lower in the DM group than in the NC group(P<0.01),also the serum MTt2 level and the ratio of MTt2/t8 in the MV group were apparently lower compared with those in the NMV group(P<0.01).② Compared with the NC group,the DM group had lower SODt2and SODt8 activities(P<0.01)and higher NOt2and NOt8 levels(P<0.05).The same changes were also found in the MV group when compared with the NMV group.③ Multiple linear regression analysis showed that MTt2 was negatively correlated with disease duration,HbA1c,and NOt2(P<0.05) and positively correlated with SODt2(P<0.01).MTt2,however,was negatively correlated with NOt8 only(P<0.05).Conclusion Type 2 diabetic patients have lower serum melatonin levels at night and abnormal circadian secretion rhythm.These changes are associated with the enhanced oxidative stress in the body and may result in the onset and development of diabetic macrovascular complications.