A total of 255 T2D patients (138 males, 117 females) aged from 25 to 70 years (mean 48.6 ± 10.7 years) and 120 healthy controls (53 females, 67 males) aged from 25 to 70 years(mean 47.1 ± 11.0 years) were enrolled to participate in this study. Physical examination, medical history and serum biochemical tests were performed to identify healthy or T2D subjects. The diagnosis criteria of T2D patients were made according to the World Health Organization in 1997 by fasting plasma glucose (FPG  7.0 mmol/L) and/or postprandial plasma glucose test (PPG  11.1 mmol/L). The inclusion criteria of all subjects were that subjects had the range of body mass index (BMI) from 18.5 to 30 kg/m2 and did not administrate any PPAR agonists in the last 3 months. Patients who were receiving insulin treatment, pregnant or lactating women, or with serious diseases such as acute myocardial infarction, cerebral vascular accident, trauma, and kidney disease or liver disease were excluded from this study. Table 1 showed the characteristic profiles of T2D patients and healthy controls. There were no statistical differences in the age, height, weight, and BMI value between T2D patients and healthy controls. All subjects were recruited from local residents in Changsha city, Hunan Province, P. R. China. The study protocol was approved by the Ethics Committee of Xiangya School of Medicine, Central South University and written informed consents were obtained before the start of this study. A total of 42 T2D patients (23 male, 19 female) were randomly selected to be only treated with 4mg rosiglitazone daily for 12 consecutive weeks without change in previous medications.