| Objective:1.First, using the normal SD rats to establish the rat model of type 2 diabetes mellitus, then the rats were treated by gastric bypass operation. Through measuring the Leptin、 POMC and NPY, We want to explore the effect mechanism on type 2 diabetes mellitus after treated by gastric bypass operation.Methods:1. Thirty male adult SD rats were fed high-fat and high-sugar diet for 4 weeks, then via intraperitoneal injection STZ to establish the rat model of type 2 diabetes mellitus. Twenty adult SD rats were selected randomly and divided into two groups:Roux-en-Y Gastric Bypass Operation group(RYGB) and No operation group (NO), every group has ten rats, and another ten SD adult male rats were selected as the Normal Control group(NC).2. After establishing the model of type 2 diabetes mellitus, the RYGB group were performed the Roux-en-Y Gastric Bypass Operation. The biood of the RYGB, NO, NC group were collected respectively to measure the leptin, blood glucose, triglyceride and total cholesterol before and after the Gastric Bypass Operation. We monitored rat weight and the consumption of water and food everyday. Four weeks after operation, the hypothalamus tissues were collected to measure the mRNA of POMC and NPY by qRT-PCR.Results:1. There were no obvious differences between the groups before establishing the type 2 diabetes mellitus model (P>0.05). At the fourth week after establishing the T2DM model, the blood glucose, total cholesterol, triglyceride and the consumption of water, food in the model group were significantly increased. The mean level of the blood glucose in the model group was increased from 6.01±1.16 mmol/L to 26.08±3.28mmol/L (P<0.01). The mean level of the weight was declined from 264±35g to 230±32g (P<0.01).2. At the 4th week after operation, the consumption of water, food and the level of the blood glucose, triglyceride, cholesterol have greatly improved in RYGB group. The mean level of the blood glucose declined from 25.85±3.21mmol/L to 6.18±0.77mmol/L (P<0.01).3. At the 4th week after operation, the level of plasma Leptin, NPY mRNA in hypothalamus were lower than NO group after operation, mean plasma Leptin and NPY mRNA in hypothalamus levels declined from 4.58±0.37ng/ml,1.89± 0.24 to 3.10±0.38 ng/ml,0.95±0.19 (P<0.01), respectively. The level of POMC mRNA in hypothalamus was significantly increased from 0.78±0.26 to 1.70±0.31 (P<0.01).Conclusions:1.The rat model of type 2 diabetes mellitus can be successfully established after the model group rats were treated by intraperitoneal injection low doses of STZ with 4 weeks feeding of high-sugar and high-fat diet.2. The type 2 diabetes mellitus can be controlled significantly after the Roux-en-Y gastric bypass operation.3. The Leptin may regulate the energy metabolism of type 2 diabetes mellitus via NPY and POMC neurons. Our results suggest that the role of Leptin/POMC/NPY signal passway may be one of the important reasons in the improving of type 2 diabetes mellitus after the gastric bypass operation. |
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