OBJECTIVETo investigate effects of glucose excursion on the oxidative/antioxidative system in subjects with different types of glucose regulation.

METHODSA total of 30 individuals with normal glucose regulation (NGR), 27 subjects with impaired glucose regulation (IGR) and 27 subjects with newly diagnosed type 2 diabetes mellitus (T2DM) were selected and recruited for 3 days' continuous glucose monitor system (CGMS) assessment. The data from CGMS was used to calculate the mean amplitude of glycemic excursion (MAGE), mean blood glucose (MBG) and its standard deviation (SDBG), area under the ROC curve when the blood glucose >5.6 mmol/L within 24 h (AUC 5.6), mean of daily differences (MODD), and mean postprandial glucose excursion (MPPGE). In all groups, the content or activity of malondialdehyde (MDA), total antioxidation capacity (TAOC) and glutathione peroxidase (GSH-Px) were detected.

RESULTSGlucose excursion parameters of subjects with T2DM or IGR were higher than those of NGR subjects (P<0.05 or 0.01). Moreover, Glucose excursion parameters of T2DM subjects were higher than those of IGR subjects (P<0.05 or 0.01). Subjects with T2DM or IGR had significant higher MDA levels and lower GSH-Px/MDA and TAOC/MDA levels compared to NGR subjects (P<0.01). T2DM subjects had even higher MDA levels and lower GSH-Px/MDA levels than IGR (P<0.05 or 0.01). According to the median of normal population for MAGE, T2DM and IGR subjects were divided into MAGE>2.6mmol/L Group and MAGE ≤ 2.6mmol/L Group. MAGE>2.6mmol/L Group had higher levels of MDA and lower levels of GSH-Px/MDA than MAGE ≤ 2.6mmol/L Group (P<0.05). There was no significant difference between the two groups (P>0.05) in terms of the levels of TAOC/MDA. Pearson correlation analysis showed that MDA was positively correlated with FPG, 2hPG, MAGE, and SBP. GSH-Px/MDA was negatively correlated with MAGE and TC. TAOC/MDA was negatively correlated with FPG. Partial correlation analysis showed that the relationship between MDA and MAGE, GSH-Px/MDA, and MAGE remained significant after adjustments for the other differences among groups.

CONCLUSIONGlucose excursion contributed significantly to promoting lipid peroxidation and decreasing antioxidation capacity than chronic sustained hyperglycemia did in the subjects with different types of glucose regulation.