High-fat diet-induced splenic, hepatic, and skeletal muscle architecture damage: cellular and molecular players.

The trend of consuming food high in calories, fat, and sugar with little nutritional value and reduced physical exercise has resulted in an alarming ratio of overweight and obese subjects worldwide. Low-grade chronic inflammation is the key feature of obesity that causes an increase in pro-inflammatory cytokines and decrease in anti-inflammatory cytokines in circulation. The current study was aimed to investigate the effect of high-fat diet on the architecture of spleen, liver, and skeletal muscle and changes in the expression of hepatic cytokines. Two groups of experimental rats were established, against control that were given different percentage of fats in their diet. After a period of sixteen weeks, rats were dissected and their organs were excised out and processed accordingly. Spleen sections of experimental groups, revealed increased recruitment of lymphocytes, sinusoidal dilatations, necrotic lymphocytes, increased ratio of white-to-red pulp, and hemosiderin and iron deposits in red pulp indicating immune system activation. Hepatic sections showed enlarged sinusoidal spaces, disruptive hepatocytes, necrosis and dilation of portal veins. Sections of skeletal muscle showed degenerating fibers, increased fat accumulation, and recruitment of macrophages. Elevated expression of IFN-γ and decreased expression of IFN-α and IFN-β cytokines verified the adverse effect of high-fat diet on immune system as well. Fats tend to accumulate in organs due to increased intake of fat-rich diet disturbing their normal function and histology. In addition, gene expression analysis of cytokines confirmed the effect of high-fat diet as an inflammatory agent.