伴有糖尿病的白内障患者和不伴有糖尿病的白内障患者眼房水中氧化状态和抗氧化能力的变化

Changes of oxidative state and antioxidant capacity in the aqueous humor of cataract patients with and without diabetes mellitus

目的通过测定眼房水中的丙二醛(MDA)的水平和总抗氧化能力(TAC)的变化来比较伴有糖尿病的白内障患者和不伴有糖尿病的白内障患者之间眼内氧化应激水平的差异。方法选择患有白内障并且行白内障超声乳化吸除联合人工晶状体植入术的患者71例入组,患者本人否认有严重系统性疾病,术前检查肝功能、肾功能和血常规均正常者,同时排除有其他眼内疾病的患者以及在术前1年内有眼外伤史的患者。每位患者取静脉血,静置1～2 h后去血浆,在超声乳化手术前行前房穿刺取前房水50～100μl。根据患者是否有糖尿病史以及术前的空腹血糖分成四组。1,2,3组患者否认糖尿病史,4组患者原有糖尿病史。1组患者30例,空腹血糖<5. 6mmol/l; 2组患者20例,空腹血糖≥5. 6 mmol/l,<7. 0 mmol/l; 3组患者10例,空腹血糖≥7. 0 mol/l; 4组患者11例,有糖尿病史。同时再根据患者的年龄分成A、B、C、D四组,A组患者9例,年龄<70岁; B组患者20例,年龄≥70岁,<80岁; C组患者34例,年龄≥80岁,<90岁; D组患者8例,年龄≥90岁。所有患者均检测眼房水中的MDA浓度和TAC浓度,同时检测各组患者血浆中的MDA浓度。结果在空腹血糖水平不同的各组患者中,房水中MDA的水平有显著统计学差异(P <0. 001),而血浆中的MDA水平无统计学差异。Pearson相关性分析显示,房水中的MDA水平与空腹血糖水平两者呈正相关(r=0. 593,P <0. 001)。在年龄不同的各组患者中,房水和血浆中的MDA水平均无统计学差异。房水中TAC水平不管在空腹血糖水平不同的各组患者中还是在年龄不同的各组患者中都没有统计学差异。但是,在空腹血糖正常且否认糖尿病史的患者中,房水中的MDA水平和TAC水平两者呈正相关(r=0. 402,P=0. 034)。结论房水中MDA的水平与血糖水平的升高有很强的相关性,所以高血糖可能是导致眼房水中脂质过氧化产物增多的一个重要因素。而房水中TAC水平不因血糖或年龄的影响而变化,是一个比较稳定的值。

Objective To compare the level of intraocular oxidative stress between cataract patients with or without diabetes mellitus by measuring the levels of total antioxidant capacity(TAC)and malondialdehyde(MDA)in the aqueous humor samples.Methods Seventy-one cataract patients who underwent phacoemulsification and intraocular lens implantation were enrolled and divided into four groups according to their history of diabetes and preoperative fasting blood glucose(FBG)levels:Group 1,FBG<5.6mmol/L,30 patients;Group 2,5.6≤FBG<7.0 mmol/,20 patients;Group 3,FBG≥7.0 mmol/L but denied the history of diabetes,10 patients;Group 4,positive history of diabetes,11 patients.Patients were also divided into four age-groups:Group A,age<70 years(y),9 patients;Group B,70y≤age<80y,20 patients;Group C,80y≤age<90y,34 patients;Group D,age≥90y,8 patients.The concentrations of MDA and TAC in the aqueous humor of each patient were measured,as well as the concentration of MDA in plasma.Results The MDA concentrations in the aqueous humor,but not plasma,were significantly different among patients in different FBG groups(P<0.001).Pearson correlation analysis showed that there was a positive correlation between the aqueous humor MDA concentration and FBG level(r=0.593,P<0.001).However,MDA levels in both aqueous humor and plasma showed no significant differences among patients with different ages.We found no significant differences in TAC levels in the aqueous humor among patients with different FBG status or ages.However,among patients with normal FBG levels and without a history of diabetes,we found positive correlation between aqueous MDA and TAC level(r=0.402,P=0.034).Conclusions The level of MDA in the aqueous humor has a strong correlation with the increase of blood glucose.Therefore,hyperglycemia is likely to be an important factor for increased lipid oxidation in the aqueous humor.However,the TAC level in the aqueous humor remains stable and is not affected by changes in glucose or age.