The Mechanism Behind the Effects of Oleuropein on Insulin Resistance in the Liver in db/db Mice / 世界科学技术-中医药现代化

ABSTRACT

This study aimed to elucidate the mechanism behind the effects of oleuropein (OL) on improving insulin resistance in obese db/db mice.Twelve 6-to 8-week-old male db/db mice were randomly divided into the model group and the OL group with 6 in each group according to their levels of blood glucose and body weight,while six C57BL/6J mice with the same age were made up for the normal group.Mice of the OL group was intragastrically administered with (50 mg·kg-1) once a day.The mice of the other groups were treated with the saline solution with the same dosage.After treatment for four weeks,OGTT test was carried out,while fast blood glucose and serum insulin were tested.RT-PCT and western blot were used to quantify the mRNA and protein expressions of certain targets in the liver.As a result,it was found that the body weight,fast blood glucose,serum insulin level and insulin resistance index were significantly decreased in the mice of the OL group when compared with model group after the treatment for 4 weeks (P＜0.05 or P＜0.01).Plasma glucose levels at each time point of OGTT tests were lower in the mice of the OL group than those of the model group (P＜0.01).The mRNA and protein expressions of InsR,IRS-1 and GLUT-2 in the mice of the OL group increased significantly (P＜0.01).In conclusion,it was demonstrated that oleuropein may reduce the blood glucose and improve the insulin resistance in db/db mice through up-regulating the mRNA and protein expressions of InsR,IRS-1 and GLUT-2 in the liver.