Objective: To investigate the effects and mechanism of postoperative insulin resistance in gastrectomy patients with preoperative oral carbohydrate.
Methods: From April to October 2011, 60 consecutive gastric cancer patients met inclusion criteria were divided into oral carbohydrate group and placebo group by randomized double-blind principles. Resting energy expenditure (REE), fasting blood glucose, insulin and triglyceride level were detected in 4 hours preoperatively. The 500 ml carbohydrate or placebo were administrated orally 2-3 hours before anaesthesia. Two group patients underwent radical distal subtotal gastrectomy under epidural compounded intravenous anesthesia. After laparotomy and before the abdomen was closed, a piece of rectus abdominis was taken and fixed in 3% glutaraldehyde. REE, fasting blood glucose, insulin and triglyceride level were detected immediately after surgery. The changes of insulin resistance index, blood triglycerides level, REE and respiratory quotient were compared pre- and post-operatively. The changes of rectus abdominis mitochondrial ultrastructure were observed by transmission electron microscopy respectively.
Results: There were 48 patients (34 males and 14 females) completed the trial. The 24 and 24 patients in oral placebo and carbohydrate groups respectively. In oral placebo group, post-operative insulin resistance index, REE, respiratory quotient, serum triglyceride level and the rectus abdominis mitochondrial damage index were 12.68 ± 3.13, (1458 ± 169) kcal/d, 0.73 ± 0.42, (0.53 ± 0.24) g/L and 1.14 ± 0.33, respectively. And the above items were 5.67 ± 1.40, (1341 ± 110) kcal/d, 0.79 ± 0.22, (1.04 ± 0.97) g/L and 0.92 ± 0.19 in oral carbohydrate groups respectively. All difference was statistically significant (t = 6.646, 2.851, 6.546, 2.542 and 2.730, all P < 0.05). Oral placebo group showed a markedly swollen mitochondria, steep membrane was not clear, mitochondria appeared vacuolated changes.
Conclusions: Preoperative oral carbohydrate could reduce the insulin resistance and REE, improve the material metabolism status in radical gastrectomy patients. The possible mechanisms should be related to promotion of insulin release and protection of mitochondrial function.