Experimental model for the evaluation of metabolic status after gastric bypass in obese rats
Authors: Mirica Radu Mihail , Ionescu Mihai , Mirica Alexandra , Ginghina Octav , Iosifescu Razvan , Rosca Adrian , Ungureanu Claudiu , Vacarasu Andrei , Zagrean Leon , Iordache Niculae 
Published: December 2020

Objective: Obesity is an exceedingly current pathology with many clinical, molecular, and psychological implications. The number of obese people has doubled in the past ten years, and we can observe an early onset of obesity. Bariatric surgery is an effective treatment for severe obesity and type 2 diabetes mellitus (T2DM); Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) are the two most prevalent types of this procedure . Nevertheless, no single mechanism has emerged that thoroughly explains the metabolic benefit and subsequent long-term effects after surgery. Webster's new collegiate dictionary defines the noun model as: 'a descriptive or analogy used to help visualize something that cannot be directly observed.' Sustained by this definition, the animal models in nutritional research are fundamental to improve human conditions. Due to the recent boost in experimental surgery, our aim in this study is to set the main technical characteristics of the gastric bypass operation and specific animal care in the metabolic surgery field we have been undertaking in our center.

Materials and methods: We chose Wistar rats fed with a high caloric diet (HCD) 82g / 100 g fat, 53/100 g saturated fat, 64/100 g carbohydrates. After 7-15 weeks of this diet, depending on the protocol understudy, a consistent three-fold greater weight gain is achieved than the usual range of the free eating chow. After approximately three months on an HCD, the obese rats manifest biochemical features of the metabolic syndrome.

Results: The weight loss for group B (By-pass) was 125 ± 16.16 g, and for group BS (By-pass + Sulodexid), it was 133.10 ± 14.38 g. Although the weight loss was higher in group BS, it is not statistically significantly higher than in group B (p = 0.345), despite administering a pharmacologically active substance in group BS. Although small (approximately 40-50 g), the difference between the control group and groups B and BS is statistically significant with p = 0.016 and 0.026 and Pearson index of 0.674 and 0.628, respectively. Statistical significance also kept the difference between group C and group S (p = 0.028, Pearson Coefficient = 0.621).

Conclusions: First of all, Metabolic surgery is the most effective weight-loss method and improvement or even remission of some diseases associated with obesity. Like today's high-calorie diet, the diet administered, mostly of adolescents, generates both obesity and its associated diseases: diabetes, hypertriglyceridemia, hypercholesterolism, thus increasing mortality and overall morbidity. Second, metabolic surgery radically improves the parameters targeting obesity (weight,% EBWL) and its associated conditions: diabetes mellitus, hypertriglyceridemia, hypercholesterolemia, strongly associated with decreasing life expectancy of the general population. Parameters targeted by gastric bypass: glycemia, TGL, CHO, hepatic steatosis, testicular atrophy registering significant improvements.