Lutein Effect On Diabetic Oxidative Stress

Objective:Accumulating evidence strongly suggests that free radicals and other oxygen reactive species are the important causative factors of diabetes mellitus and its complications. Increasing evidence show that antioxidants such as lutein have potential benefits on preventing hyperglycemia and diabetes mellitus.This study aimed to investigate the association between lutein and diabetes mellitus and the effect of lutein on diabetic nephropathy in alloxan-induced diabetic rats.Method:1.The experimental diabetes in Sprague-Dawley rats was induced by alloxan and the rats were were given lutein intragastrically for 4 weeks,then the kidney weight,the ratio of kidney weight to body weight(KW/BW),blood urea nitrogen(BUN),serum creatinine(SCr),creatinine clearance rate(CCr),urinary protein,serum level of lutein, renal tissue superoxide dismutase(SOD) and glutathione peroxidase(GSH-Px) activities,glutathione(GSH) and malondialdehyde(MDA) levels and and renal tissue tumor necrotic factorα(TNF-α),interleukin 6(IL-6) levels were determined.2.We describe a simple isocratic HPLC method for the accurate and precise measurement the major carotenoids in plasma using UV detection.Reference ranges three carotenoids are determined in a healthy population group.The chromatographic analysis was performed using an analytical scale C₁₈ reversed phase column(250 mm×4.6 mm i.d.) The mobile phase for chromatography was methanol:acetonitrile: tetrahydrofuran(60:20:20) containing 0.01%ascorbic acid.The flow rate was set at 1 mL/min.Chromatographic runs were monitored at 450nm.3.Investigate the serum lutein level and oxidative stress in patients with type 2 diabetes mellitus.The concentration of fasting serum glucose,triglyceride and total cholesterol,serum lutein,lycopene,β-carotene,vitamin E,and the activity of serum superoxide dismutase(SOD),serum glutathione peroxidase(GSH-Px),and serum malondialdehyde(MDA) level in 99 patients with type 2 diabetes and 83 healthy subjects were measured. Results:1.Compared with the diabetic group,kidney weight,KW/BW,BUN,SCr,urinary protein were decreased in lutein group(P＜0.05),the renal tissue SOD and GSH-Px activities, GSH were increased(P＜0.05) and MDA level was decreased(P＜0.05) in lutein group, and renal tissue TNF-α,IL-6 levels were decreased significantly in lutein group (P＜0.05).2.The average retention time for lutein,lycopene andβ-carotene were 4.3min,12.4min, 17.0 min.The recovery was as follows:lutein 97.98～102.80,lycopene97.24～101.76,β-carotene 98.56～100.4,the intra-day and inter-day RSD were 2.26%and 3.02%, 4.34%and 5.02%,1.81%and 2.52%for lutein lycopeneβ-carotene respectively。90 healthy inhabitants were enrolled in this study.Mean plasma concentrations of lutein, lycopene andβ-carotene are are 0.34±0.17μg/ml,0.28±0.16μg/ml,0.49±0.25μg/ml. the results showed that this method was simple,rapid and accurate.3.Compared with the healthy subjects,the average level of lutein[(0.26±0.16) vs(0.34±0.15),μg/ml],lycopene[(0.22±0.17) vs(0.28±0.16),μg/ml],β-carotene[(0.41±0.24) vs(0.50±0.25),μg/ml],SOD[(94.27±20.05)vs(112.77±11.67),U/ml],GSH-Px [(131.85±54.33) vs(173.21±59.14),U/ml]in DM decreased significantly(P＜0.05),the MDA[(5.27±2.34) vs(3.84±1.97),nmol/ml],IL-6[(36.45±11.83)vs(26.98±5.03), pg/ml]level increased significantly(P＜0.01).R values of Person correlation coefficients between serum lutein,lycopene,β-carotene and SOD and GSH-Px were positive,R values of Person correlation coefficients between lutein,lycopene,β-carotene and MDA were negetive(P＜0.05),R values of Person correlation coefficients between serum lutein,β-carotene and IL-6 were negetive(P＜0.05),the results of multiple linear regression analysis showed that after adjusted by BMI and age,lutein was negetive correlated with serum MDA,IL-6,and positive corrslated with SOD,GSH-Px.Conclusion:Oral administration of lutein can delay the renal injury of diabetic rats.The possible mechanism may be related with the effect of lutein in increasing activities of antioxidant enzymes and reducing lipid peroxidation and decreasing the cytokines in rat kidney There were close relationship between the serum biomarkers indicative of oxidative stress and serum carotenoids in patients with type 2 diabetes millitus.the serum MDA,IL-6 level decreased and SOD,GSH-Px increased as serun lutein level incresed. This show that lutein can decresed xidative stress,potentially decreased IL-6 expression,alleviate the side effects of excessive IL-6 expression.