Obesity Resistance And Metabolic Differences In Obese Rats

Obesity is a multi-factor and multi-gene disease involving a complex process of change which also is one of the most important risk factors of many metabolic related diseases on early stage.In order to facilitate research, animal models of obesity produced by artificial fat diet have always been considered as a powerful tool. According to body mass difference, we can get diet-induced obesity resistant animals (DIO-R), diet-induced obesity animals (DIO) and animals with body weight among DIO and DIO-R with same high fat diet. Research on the complicated mechanisms of obesity through comparative model of obesity is quite limited.So in our study, the differences of metabolism on DIO-R rats and DIO rats were analyzed.After successfully established DIO and DIO-R animal models, we made a study on lipid metabolism and pancreatic function through methods of real-time PCR, ELISA, Western blot, pathological HE staining and detecting the related biochemical indexes.Results showed the mRNA expression of SREBP1c, ACC, FAS in DIO-R rats were significantly lower than obesity rats group (P<0.01) after 25 weeks feeding. Compared to DIO rats, the serum insulin level of DIO-R rats were lower (P<0.05). There were fatty degeneration and pancreatic tissue damage in both DIO-R rats and DIO rats. Apoptosis-related proteins on pancreas have been expressed in DIO-R rats and DIO rats, including Bik, Bax, Cleaved caspase3 and Bcl-2 as an inhibitor of apoptosis protein. All these protein expressions were significantly higher than the normal group.These results suggest that lower expression of SREBP1c lead to the obesity resistance directly which is also as the reseaon on differences of lipid metabolism and apoptosis in pancreas. Our study reveals the meachinsm of obesity and obesity-resistance occurance from another aspect which may provide a good animal model for clinic pharmacy.