Effect of dietary change on the expression of AgRP in hypothalamus of rats

doi:10.3969/j.issn.1002-7386.2015.08.004

Abstract：Objective To observe the effect of dietary change on the expression of AgRP in hypothalamus of rats,and to explore the action mechanism of AgRP in pathogenesis of obesity.Methods Eighty male Wistar rats weighted 100~120g were randomly divided into high-energy diet group ( n =40),hunger group ( n =20),control group ( n =20).The rats in high-energy diet group were given self-made high-energy food,the rats in control group and hunger group were fed with basal food.After 12 weeks, the rats in high-energy diet group whose weight exceeded30 % of mean weight in control group were regarded as diet-induced obesity group ( DIO group) ,however,the rats in hungry group were fasted for 72h,free to drink in the meantime.Then the expression levels of AgRP were detected by immunohistochemistry (IHC) and Western Blotting for all the rats.Results The results by IHC showed that the expression levels of AgRP in hypothalamus of rats in DIO group (5531.10 ±330.40) and hungry group (49016.7 ±410 2.4 ) were significantly higher than those in control group(919.62 ±325.98) ( P <0.01),however,there were no significant differences between DIO group and hungry group ( P >0.05).The results by Western blotting showed that the expression levels of AgRP in hypothalamic of rats in DIO group(0.99 ±0.01) and hungry group(0.87 ±0.02) were significantly higher than those in control group(0.67 ±0.01) ( P <0.01),but there were no significant differences between DIO group and hungry group ( P >0.05).Conclusion Long-term high-energy diet can result in obesity,and the overexpression of AgRP in hypothalamus may be one of the main factors which can lead to the increase of food intake,weight gain and obesity.During starvation condition, the increase of AgRP expression in hypothalamus may be caused by the common effects of the reduction of leptin,insulin and sugar within organism.