The effect of bariatric surgery on the expression of Growth Differentiation Factor-15/Macrophage-Inhibitory Cytokine-1 (GDF-15/MIC-1) in rat.

Abstract

Reduced appetite and loss of preference to nutrition dense high-fat diet are present after bariatric surgery. But the mechanism responsible for these changes in biological activities remains unclear. Similar changes in biological activities have been observed with growth/differentiation factor-15/macrophage-inhibitory cytokine-1 (GDF-15/MIC-1) treatment alone. To assess the effect of bariatric surgery on GDF-15/MIC-1expression and circulating level in rodent model. The Affiliated Hospital of Xuzhou Medical University, Xuzhou Jiangsu 221,006, P. R. China. Among 40 fatty Sprague-dawley (SD) rats, 30 randomly receive low-dose STZ to induced diabetes and were randomly assigned to Roux en Y gastric bypass (RYGB, n = 10), Sleeve gastrectomy (SG, n = 10), and SHAM (n = 10). The remaining fatty SD rats were assigned to Normal control (NC, n = 10). Rats were followed for 8weeks postoperatively. Circulating levels of GDF15 and tissue (gastrointestinal and liver) expression were assessed after surgery. Preoperative oral glucose tolerance test (OGTT), and Insulin tolerance test (ITT) were reassessed postoperatively. Changes in bodyweight and food intake were also recorded. Bariatric surgery significantly increased circulating plasma level of GDF15 (p < 0.05). Postoperatively, tissue expression of GDF15 was significantly higher in the stomach pouch, jejunum, and ileum of rats in the RYGB group as well as ileum of rats in the SG group compared to Sham and NC (p < 0.05). Higher Expression of GDF15 in the stomach pouch of the SG group was not statistically significant compared to the stomach of Sham and NC group. GDF15 expression in the liver was significantly less in the RYGB group (p < 0.05). Bariatric surgery significantly increases circulating levels and gastrointestinal tissue expression of GDF15. Given that GDF15 is an important regulator of energy homeostasis, further studies are needed to ascertain the relevance in bariatric surgery.