Effects Of Chlorogenic Acid On Expression Of Glucose Transporter And Proglucagon Gene In Intestine From High-Sucrose-High-Fat-Fed SD Rats

This study investigated the changes of physiological and biochemical indexes of SD rats fed on high-sucrose-high-fat diet, and analyzed the effects of chlorogenic acid (CGA) on the glucose transporter (SGLT-1and GLUT-2) and proglucagon gene (PLG) mRNA expression in different intestinal segment form SD rats fed on high-sucrose-high-fat diet. At the same time, it revealed the effects and relevant mechanism of chlorogenic acid on intestinal glucose homeostasis in high-sucrose-high-fat-fed SD rats.After one week adaptively feeding fourty male Sprague-Dawley rats (4weeks old,100-120g body weight) were randomly assigned to four groups:normal control (NC, n=10), high-glucose high-fat diet group (HSF, n=10), high-glucose high-fat diet with low doses of CGA (CGA20, n=10), and high-glucose high-fat diet with high doses of CGA (CGA90, n=10). The control group were fed a normal chow diet and the others were fed high-sucrose-high-fat diet, water and feeds were available to the rats ad libitum. The low/high doses of CGA intervention groups were individually treated with20mg/kg and90mg/kg, while the control group and high-sucrose-high-fat diet group were only perfused with physiological saline once per day. Oral glucose tolerance test was performed by glucose meter, serum insulin levels was detected using ELISA. The expression of glucose transporter (SGLT-1and GLUT-2) and PLG mRNA in different intestinal segments (duodenum, jejunum, ileum and colon) on four experimental groups were analyzed using quantitative real-time PCR.Results showed HSF group had bad glucose tolerance compared with normal group, both low dose and high dose of CGA had better glucose tolerance ompared with HSF group. At the same time, the serum insulin level in HSF group was significantly lower than normal group, and high dose of CGA group was higher than HSF group significantly. Furthermore, compared to normal control group, however, which was inhibited by high dose CGA intervation, while the low dose of CGA had no significant inhibition effect. The expression of GLUT-2in various intestinal segments were sharply down-regulated by the action of high-sucrose-high-fat diet, compared to the normal control group. CGA intervention improved the expression of GLUT-2, high dose of CGA had better effect and the expression level was closer to that of the normal control group. In addition, the expression of PLG in four intestine segments were increased in other three treatment groups compared with normal group, and low dose of CGA effect was particularly obvious.All the data above show that high-sucrose-high-fat diet can cause glucose metabolism disorder in rat intestine, and affect the body glucose homeostasis. CGA can regulate the rate of intestinal glucose metabolism by regulating the intestinal glucose transporter and glucagon gene expression, thereby it can control the levels of blood glucose and insulin to maintain glucose homeostasis.