The Relationship Between Caveolin-1 And Dietary Induced Obesity And Cardiovascular Disease In Rats

Objective To study the effect of high-fat diet on obesity in rats and the effect of dietary fat on the expression of caveolin-1, endothelial nitricoxide synthase (eNOS) in artery of rats. Reveal the possible mechanisms of diet induced obesity and cardiovascular diseases, and provide evidences for preventing obesity and cardiovascular diseases.Methods Thirty-six male SPF Sprague-Dawley rats (150g~160g) were randomly divided into high-fat diet group (HF, n=27) and control group (CF, n=9) on the basis of body weight after acclimated to the environment and chow diet for 1 week. Then either high-fat or chow diet were given for fifteen weeks. The dietary induced obesity (DIO) rats were designated from HF group according to the final body weight (weights more than x +1.96s of control group). Then half of the DIO rats were switched to standard diet (DIO- HF/LF), the other DIO rats (DIO-HF) and CF rats continued their primary diet for another eight weeks. Blood samples were collected by caudal vein for the measurement of fast blood glucose and blood lipid levels at the beginning of the test and before the DIO rats were switched with different diets. General conditions were observed daily, and body weights were measured weekly. At the end of the experiment by the 23rd week, all rats were sacrificed by decollation after 10h fasting, plasma and serum were collected for testing the concentrations of blood glucose and blood lipids. The abdominal white adipose tissue (testicular, renal and waist sites) were separated and weighed. Arteries were immediately excised, frozen in liquid nitrogen and stored at -80°C until analysis. The expressions of caveolin-1 were measured by reverse transcription-polymerase chain reaction (RT-PCR), western blotting and immunohistochemistry. And the expressions of eNOS was also measured using western blotting.Results At the end of 15 weeks, 14 of the 27 rats fed with high-fat diet were designated as diet induced obesity (DIO). The levels of body weight, fast blood glucose, total cholesterol and triglycerides were higher significantly in DIO group than those in control groups (P<0.05), and no significant difference were found between DIO-HF/LF and DIO-HF groups. After switched to chow diet for 8 weeks, the final weights of DIO- HF/LF were lower than that of DIO-HF rats whereas higher than that of CF rats (P<0.05). Fat deposits, adipose relative weight, and the level of caveolin-1 expression in DIO-HF group were the highest among the three groups, while the expression of eNOS protein was the lowest (P<0.05), and no significant difference was found in the other two groups.Conclusions①High-fat diet (4.62kcal/g )has an impact on the development of obesity in SD rats. When switched to chow diet for another 8 weeks, DIO rats gained much less body weight.②Increased expression of caveolin-1 and decreased expression of eNOS were associated with the obesity of DIO rats, and might increase the risk of cardiovascular disease.③Switched to chow diet of DIO rats could reduce the body weight gain and decrease the expression of caveolin-1, which might reduce the risk of cardiovascular disease by decreased the expression of eNOS.