Effects of exenatide on autophagy and occurrence of brown adipocytes for white adipose tissue in obese rats

Abstract

Objective To explore the effects of exenatide on autophagy and occurrence of brown adipocytes for white adipose tissue in obese rats. Methods Twenty 4-week-old male SD rats were randomly divided into 2 groups according to random number table: control group with normal fat diet (n=10)and high fat diet group(HFD group,n=10). The rats in HFD group was fed with high-fat diet for 12 weeks, then they were randomly divided into intervention group(Exe group) and obesity group. The rats in the Exe group were subcutaneously injected with exenatide 10 μg·kg-1·d-1 through abdominal wall for 10 weeks, while the rats in control and obesity group were subcutaneously injected with saline solution. Western blotting and real time polymerase chain reaction (RT-PCR) were used for protein and gene expression assays. One-way analysis of variance and independent-samples t test were used for statistical analysis. Results (1) After 4 weeks of high-fat diet feeding, the body weight in the HFD group was increased than that in the control group ((472± 38) vs (420 ± 28) g , t=3.302, P=0.011). After 4 weeks of exenatide treatment, the body weight was significantly decreased in the Exe group than the obesity group ((598 ± 24) vs (696 ± 35) g ,t=4.554, P= 0.002). (2) Compared with the obesity group, the level of autophagy-related protein light chain 3B(LC3B) II/LC3BI was increased in the Exe group(2.17 ± 0.12 vs 1.16±0.08, t=3.584 , P<0.05). The level of uncoupling proteins 1(UCP-1, which represents the occurrence of brown adipocytes for white adipose tissue) was increased than that in the obesity group(1.63 ± 0.09 vs 0.82 ± 0.06, t=8.397, P=0.0014). Conclusion Exenatide may reduce the body weight in obesity rats induced by high-fat-diet. The mechanism maybe promotion of the autophagy and converting into brown fat in white adipose tissue. Key words: Obesity; Exenatide; Autophagy; White adipose tissue; Brown adipose tissue