Effect of etanercept, a tnf-alpha inhibitor, on depressive-like behavior in cafeteria diet-fed rats

Abstract

Background: Obesity has been shown to be associated with depression. Recent studies have reported that obesity is not only as a metabolic disorder but also as an inflammatory disease. In this study we explored the effect of etanercept, a TNF-α inhibitor, on depressive-like behavior in cafeteria diet (CD)-fed rats. Methods: Six-week-old male Wistar Albino rats (300-350 g) were divided into three groups (n=10): Control (not exposed to CD), CD-fed (exposed to CD during 5 weeks) and CD-fed+etanercept (exposed to CD and treated with etanercept (0.8 mg/kg/weekly/ subcutaneously during 5 weeks). CD was used to generate diet-induced obesity. The body weights of animals were measured weekly. Forced swimming test (FST), the sucrose consumption and preference test were used to investigate antidepressant effect of etanercept. One-way ANOVA and Tukey’s post hoc test used for statistical analysis. Results: After 5 weeks, the body weight of CD-fed group was higher than control group (p<0.001) and CD-fed+etanercept group was lower than CD-fed group (p<0.05). In FST, there were differences between three groups in terms of immobility time during second day of testing (F(2,27)=8.174, p=0.017). CD-fed group exhibited more immobility than control group (p<0.01), while there was no difference between control and CD-fed+etanercept group (p>0.05). Sucrose consumption and sucrose preference in CD-fed group was lower than control group (p<0.05). However, the behavior of rats in CD-fed+etanercept group did not differ from the control group (p>0.05). Conclusions: The results indicate the antidepressant effect of etanercept on diet-induced obesity and TNF-α may play crucial role on obesity-related mechanisms.