Objective      To investigate whether dietary capsaicin can prevent insulin resistance induced by high fat diet in mice.       Methods      Thirty male C57BL/6J mice at 8 weeks old were divided into 3 groups randomly

with 10 in each group

and then fed with normal diet (ND)

high fat diet (HD)

and high fat diet plus capsaicin (HC

0.01% capsaicin inside) respectively

for 20 weeks. Their fasting blood glucose and body weight were measured every week. Glucose tolerance and insulin tolerance test were tested at the end of the 20th week

and then the mice were sacrifice after anesthesia. Plasma levels of insulin

lipids (total cholesterol

triglycerides

low-density lipoprotein cholesterol and high-density lipoprotein cholesterol) were detected. Weights of visceral fats (mesenteric fat

perirenal fat and supraepididymal fat) was measured. Western blotting was used to detect the expression of transient receptor potential vanilloid 1 (TRPV1) and glucose transporter type 4 (GLUT4) in above fat tissues.       Results      Twenty weeks of high fat diet successfully induced insulin resistance model in mice. High fat diet plus capsaicin prevented high fat diet induced elevation of mice body weight

increase of fasting blood glucose

and abnormality of glucose tolerance

rise of plasma insulin and decrease of insulin sensitivity. Compared with the HC group

there was more visceral fats in HD group (P0.05); but there was no significantly difference between the ND group and HC group (P0.05). Protein levels of TRPV1 and GLUT4 in the fat tissues was significantly lower in HD groups than the ND and HC group (P0.01).       Conclusion      Dietary capsaicin up-regulates the TRPV1 and GLUT4 levels

and thus prevents high fat diet-induced insulin resistant in mice.