Effect of obesity on liver immune response to inflammatory stimuli in a diet-obesity model of zebrafish (Danio rerio)

We used a Diet-Induced-Obesity approach using the zebrafish (Danio rerio) based on overfeeding to analyze the liver transcriptomic modulation in the disease and to determine how the obesity affects the immune response against an acute inflammatory stimulus as the lipopolysacharide (LPS). Overfed zebrafish were obese and showed signs of steatosis in their liver. Furthermore, the gene modulation profile resembled to that observed in humans. After the inflammatory stimulus, there was a clear differential immune response in normal and overfed fish. In normal fish, the response to LPS reported a typical host defensive reaction comparable to the one occurring in stimulated mammals whereas there was not any significantly modulated gene when comparing the expression of liver from LPS-stimulated with non-stimulated obese zebrafish. Healthy fish were fed two times a day, one with Artemia and the other with standard fish chow while obese fish were fed fish chow two more times a day during 8 months. 10 μg of pure LPS (Sigma) or PBS was intraperitoneally injected and livers were sampled and pooled at 3 hours post injection.