J Korean Surg Soc JKSS Journal of the Korean Surgical Society 1226-0053 2093-0488 The Korean Surgical Society 10.4174/jkss.2010.79.3.155 Original Article Effect of Roux-en-Y Gastric Bypass on Body Weight, Ghrelin and PYY3-36 in Diet-induced Obese Rats Lee Sang Kuon M.D. Jung Hun M.D. Jeon Hae Myung M.D. Kim Eung Kook M.D. Department of Surgery, College of Medicine, The Catholic University of Korea, Seoul, Korea. Corresponding author (luislee@catholic.ac.kr) 09 2010 03 09 2010 79 3 155 162 05 03 2010 15 06 2010 Copyright © 2010 The Korean Surgical Society 2010 Purpose

Obesity is considered an epidemic worldwide. Nonsurgical treatment such as dietary, physical and pharmacological therapies have limited success and thus, bariatric surgery is the ultimate option. Roux-en-Y gastric bypass (RYGB) is a bariatric procedure, which is a restrictive and malabsorptive procedure simultaneously. The purpose of this study was to develop surgical rat models of bariatric surgery and analyze the effect of gastric bypass on body weight, ghrelin and polypeptide YY3-36 (PYY3-36) changes in rats.

 Methods

RYGB, sleeve gastrectomy (SG) and sham operation were performed in diet-induced obese rats and compared to obese control and normal control rats.

 Results

In RYGB group, 20.7±8.56% of weight loss was achieved on postoperative day 18 and maintained thereafter. This outcome was significant compared to SG (8.8±1.82%) and sham operated (6.2±2.45%) groups. When pre- and postoperative ghrelin levels were compared, there was a significant decrease in RYGB group (P<0.028); nonetheless, there was no difference in SG and sham operated groups. When pre- and postoperative PYY3-36 levels were compared, there was a significant increase in RYGB (P<0.028), SG (P<0.031) and sham operated (P<0.031) groups.

 Conclusion

We developed surgical rat models of RYGB and SG. Those rats that underwent RYGB lost significant body weight and maintained the weight thereafter. The decrease in ghrelin and increase in PYY3-36 may be associated with loss of appetite and delay in intestinal transit time with subsequent weight loss maintenance. In the future, this rat model would serve as a tool for further study on endocrine regulation of obesity.

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Completed Roux-en-Y gastric bypass. Gastrojejunostomy (big arrow) and jejunojejunostomy (small arrow) are shown.

Schematic figure of Roux-en-Y gastric bypass. The biliopancreatic limb from Treitz ligament is about 16 cm in length and the alimentary limb, about 10 cm in length.

Completed sleeve gastrectomy.

Weight changes expressed as percentage of weight loss. From postoperative day 7 on, Roux-en-Y gastric bypass (RYGB) group achieved significant weight loss comparing to sleeve gastrectomy (SG) and Sham operated (Sham) groups. *P<0.05.

Pre- and postoperative ghrelin levels. The decrease of ghrelin level in Roux-en-Y gastric bypass (RYGB) group was significant, while in sleeve gastrectomy (SG) and Sham operated (Sham) groups was not significant. *P=0.028.

Pre- and postoperative PYY3-36 levels. The increase of PYY3-36 level in Roux-en-Y gastric bypass (RYGB) group was significant, as well as in sleeve gastrectomy (SG) and Sham operated (Sham) groups. *P<0.05.