Abstract: Objective:To investigate the effects of RouxenY gastric bypass surgery on the obesityrelated indexes, glycolipid metabolism indexes and expression of peroxisome proliferatoractivatived receptorγ (PPARγ) protein in visceral adipose tissues of rats with metabolic syndrome.
Methods:After 40 Sprague Dawley (SD) male rats with the age of 7-8 weeks were adaptively fed for 1 week, 30 rats were selected randomly and were fed with highfat, high glucose and high salt diet combined with sucrose water for 12 weeks, and then 24 rats with metabolic syndrome were screened for eligibility and were allocated into the model group (n=11) and the operation group (n=13) 〖HQK〗based on the randomized complete block design. Rats of the model group and operation group received transection and reanastomosis of the gastrointestinal tract and RouxenY gastric bypass surgery, respectively. Other 10 rats receiving normal feeding were divided into the control group. After executing rats at postoperative week 5, the levels of PPARγ protein in visceral adipose tissues around mesentery, double kidneys and bilateral epididymis were detected by the Western blot. Observation indexes: (1) obesityrelated indexes included food intake before operation and at postoperative week 5, body weight, abdominal circumference, Lee′s index, visceral adipose weight at postoperative week 5 and visceral adipose coefficient. (2) Glycolipid metabolism indexes included fasting plasma glucose before operation and at postoperative week 5, fasting serum insulin, homeostasis model assessmentinsulin resistance (HOMAIR), total cholesterol (TC), triglyceride (TG), high density lipoprotein cholesterol (HDLC), low density lipoprotein cholesterol (LDLC) and free fatty acid (FFA). (3) Level of PPARγ protein in visceral adipose tissues at postoperative week 5.  Measurement data with normal distribution were presented as ±s. Comparison among groups was analyzed using the ANOVA, and comparison between groups was analyzed using the LSDt test. Repeated measures data were analyzed by the repeated measures ANOVA.
Results:Three rats in the operation group were dead at postoperative week 1 with a mortality of 3/13 and no death was occurred in other groups. The consumption of food, body weight, abdominal circumference, Lee′s index before operation and at postoperative week 5 were (26.9±1.5)g, (499±46)g, (18.2±0.4)cm, 309±9 and (27.7±2.1)g, (547±43)g, (18.6±0.5)cm, 312±8 in the control group, (26.1±1.8)g, (584±42)g, (19.3±0.6)cm, 317±13 and (28.8±1.7)g, (677±39)g, (20.6±0.7)cm, 334±11 in the model group, (25.9±2.1)g, (579±47)g, (19.4±0.5)cm, 311±5 and (17.5±0.8)g, (470±40)g, (18.1±0.4)cm, 302±4 in the operation group, respectively, with no significant difference in the above indexes before operation among the 3 groups (F=0.821, 0.784, 0.813, 0.642, P>0.05), and with significant differences in the changing trends of above indexes of 3 groups between before operation and postoperative week 5 (F=4.650, 3.852, 4.362, 4.042, P<0.05). The visceral adipose weight at postoperative week 5 and visceral adipose coefficient were (34±6)g and 6.2%±0.5% in the control group, (55±6)g and 8.2%±0.6% in the model group and (28±6)g and 6.1%±0.5% in the operation group, respectively, with significant differences in the above indexes (F=16.750, 14.686, P<0.05). There were significant differences in the visceral adipose weight at postoperative week 5 not only between control group and model group but also between model group and operation group (t=4.287, 5.511, P<0.05), and no significant difference between control group and operation group (t=1.225, P>0.05). There were significant differences in the visceral adipose coefficient at postoperative week 5 not only between control group and model group but also between model group and operation group (t=4.435, 4.657, P<0.05), and no significant difference between control group and operation group (t=0.245, P>0.05). The fasting plasma glucose, fasting serum insulin, HOMAIR, TC, TG, HDLC, LDLC and FFA before operation and at postoperative week 5 were (4.3± 0.9)mmol/L, (15.1±4.9)μmol/L, 2.19±1.43, (1.12±0.13)mmol/L, (1.3±0.5)mmol/L, (1.32± 0.19)mmol/L, (0.9±0.4)mmol/L, (131±17)mmol/L and (4.3±1.2)mmol/L, (14.8±5.3)μmol/L, 2.29±1.37, (1.07±0.16)mmol/L, (1.2±0.7)mmol/L, (1.28±0.22)mmol/L, (0.8±0.5)mmol/L and (134±19)mmol/L in the control group, (6.1±0.7)mmol/L, (30.1±1.8)μmol/L, 7.86±1.56, (3.32± 0.14)mmol/L, (2.5±0.6)mmol/L, (0.81±0.21)mmol/L, (2.8±0.7)mmol/L, (178±18)mmol/L and (6.1±0.7)mmol/L, (31.6±2.1)μmol/L, 8.50±1.66, (3.43±0.12)mmol/L, (2.7±0.5)mmol/L, (0.84±0.24)mmol/L, (3.1±0.5)mmol/L, (182±19)mmol/L in the model group, (6.2±0.6)mmol/L, (29.6±2.7)μmol/L, 7.43±1.03, (3.36±0.15)mmol/L, (2.6±0.5)mmol/L, (0.79±0.17)mmol/L, (2.9±0.6)mmol/L, (180±17)mmol/L and (4.5±0.8)mmol/L, (19.5±1.0)μmol/L, 5.17±0.25, (1.46±0.08)mmol/L, (1.5±0.4)mmol/L, (1.09±0.18)mmol/L, (1.2±0.3)mmol/L, (146±16)mmol/L in the operation group, respectively . There was no significant difference in the above indexes before operation among the 3 groups (F=0.625, 0.746, 0.813, 0.649, 0.754, 0.823, 0.587, 0.648, P>0.05). There were significant differences in the changing trends from before operation to postoperative week 5 among the 3 groups (F=4.714, 14.921, 18.971, 20.544, 5.731, 6.143, 10.276, 6.607, P<0.05). Level of PPARγ protein in visceral adipose tissues at postoperative week 5 in the control group, model group and operation group were 0.79±0.26, 0.22±0.17, 1.18±0.37, respectively, showing a significant difference among the 3 groups (F=8.988, P<0.05). There were significant differences in the level of PPARγ protein not only between control group and model group but also between model group and operation group (t=3.178, 4.084, P<0.05), and no significant difference between control group and operation group (t=1.494, P>0.05).
 Conclusion:RouxenY gastric bypass surgery can reduce the visceral fat accumulation of rats with metabolic syndrome, improve metabolism of glucose and lipid and increase expression of PPARγ protein in visceral adipose tissue.