| Adiponectin is a special adipocytokine, with the adipose tissue volume became larger, its serum level decreased. Low plasma levels of adiponectin were found to associate with obesity, metabolic syndrome, diabetes and many other human diseases. From animal obesity experiments and human obesity studies, the level of adiponectin has been shown to decrease, and during these experiments people also found some subjects developed to obesity while some did not and they had different susceptibility to obesity. Since the level of adiponectin had great relation with obesity and glucolipid metabolism, it may play an important role in the prevention of obesity and insulin resistance. So it is meanfull to study the relation between adiponectin and glucolipid metabolism in rats which were fed under the same condition of the HFD, and to discuss the potential role of adiponectin in the development of different susceptibility to obesity.Objection:To explore the method of establishing high-fat dietary (HFD) induced obesity (DIO) and obesity-resistant rats (DIO-R), to study the relationship between the expression of adiponectin mRNA in adipose tissues and the levers of serum adiponectin concentration and glucolipid metabolism in DIO and DIO-R rats, which were fed under the same condition of the HFD, and to discuss the potential role of the adiponectin in the development of different susceptibility to obesity. Methods:1. 80 male Sprague-dawley (SD) rats were randomly divided into control group (n=10) and high-fat group (n=70), rats in control group were fed with basic diet for 20 weeks, and rats in high-fat group were fed on HFD for 12 weeks, DIO rats and DIO-R rats were selected randomly according to their body weight. They were continuously fed on the HFD for another 8 weeks. During this 20 weeks period, serum was collected every four weeks.2. 20 weeks later, rats were killed, serum was collected for testing of lipid, fasting glucose and insulin, HOMA-IR index of each group were calculated, based on fasting glucose and insulin,to indicate insulin sensitivity.3. Total adipose tissues RNA were extracted using Trizol Reagent (Promega), the levels of adiponectin mRNA expression in visceral fat tissue were detected by real time PCR (RT-PCR) technique. The level of serum adiponectin was measured by enzyme linked immunosorbent assay (ELISA). Associations between the lever of serum adiponectin and biochemical parameters were studied by correlation analysisResults:1. The body weights, wet weight of fat pad and the ratio between fat and body weight in DIO rats were significant higher than that of DIO-R rats. The serum levels of TC, TG, BG,LDL and insulin in DIO rats were significant higher than that of DIO-R (P<0.05), and HDL-C levels in DIO and DIO-R rats were significant lower than that of control rats.2. The relative levels of adiponectin mRNA in visceral fat tissue were significant lower than that of DIO-R (P<0.05) after feeding on HFD for 20 weeks.3. With the high -fat diet time, the levels of serum adiponectin in DIO rats turned to be a downward trend. The levels in DIO rats were significant lower than that of DIO-R rats after 12 weeks of HDF feeding(P<0.05), and the difference became more apparent after 12 weeks of HDF feeding(P< 0.01).4. The levels of serum adiponectin were reversely correlated with body weight(p<0.05), insulin(p<0.05), were positively associated with BG(p<0.05). Conclusion: DIO and DIO-R rats exsited metabolic disorder, hyperinsulinism also exisited in DIO rats; the levels of adiponectin were different in DIO and DIO-R rats, but we could not see there exsited any relation between the level of adiponectin and glycolipid indexs according to the results of correlation analysis, so we could not conclude that adiponectin had any effect on the development od DIO and DIO-R rats. |
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