| ObjectiveRoux-en-Y gastric bypass surgery was performed on SD rat models with nutritional obesity and dyslipidemia. The surgical effect on weight loss, lipid profile improvement and leptin resistance were documented to analyze for the underlying mechanism.MethodsMale SD rat models with nutritional obesity were established. The rats were randomly divided into the operation group (R group), sham surgery group (S group), dietary control group (F group) and the blank control group (C group). Rats were closely monitored for 8 weeks before and after the surgery, in terms of changes of weight, body length, amount of food intake, as well as levels of triglyceride, cholesterol, free fatty acid and plasma leptin. Frozen section of myocardial tissue and liver tissue were done, and were stained for lipid to examine the pathology of fat deposition.Results1. After 1 week, food intake in R, F group were significantly lower than they were preoperatively (p<0.01). From the 4th week, the fasting body weight of R group decreased significantly compared with F group (p<0.05); on the 4th-8th week, R group has a small amount of feeding increase.2. Four weeks after surgery, the TG level of R group was lower than F group (p<0.05); to the 8th week, TG level of R group was significantly lower than it was preoperatively (p<0.05). On the 4th week, TC level of R group compared pre- and postoperatively p<0.01, there was statistical different compared with the F group (p<0.05), On the 8th weeks, TC level of R group was significantly lower than it was preoperatively.3. FFA levels of R, F group decreased gradually at each time point after the surgery. On the 4th to 6th weeks, the level of FFA in R group is lower than that in group F (p<0.05). Leptin levels of R group began to decrease from the 2nd week; on the 4th week compared with preoperation p< 0.05; From the 6th week, the decreased levels of Leptin in R group were significantly higher than F group (p<0.05). 4. The analysis of relationship between the postoperative changes in appetite, fasting body weight, blood lipid and leptin levels in SD rats, and the relative analysis of appetite and weight changes in R group showed r=-0.64, p<0.05. The correlative coefficient between TG levels and food intake were r=0.65,p<0.05. Between TG and FFA levels r=0.91,p<0.01; FFA and Leptin levels were significantly correlated between each other (r=0.86,p<0.01).Conclusions1. RYGB has better short-term effect on weight loss, lipid profile improvement and improved leptin resistance in comparison of the group with dietary control. Long-term effect awaits further verification.2. RYGB treats obesity and dyslipidemia by restriction and malabsorption of food intake. Improvment of leptin resistance and FFA level were also related. The underlying mechanism awaits further study.3. RYGB improves and prevents cardiovascular fat deposition and fatty degeneration of hepatic cells. Long-term effect awaits further verification.
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