Investigation of the relationship cognitive functions, sensory and motor behavior, and extracellular matrix proteins in mice on the high-fat diet

Obesity is a worldwide health problem, and many people suffer from obesity and related diseases. Eating habits play an important role in developing obesity, and previous studies demonstrate that low-quality diets have adverse effects on the brain and behavior such as memory loss or impairment in the appetite and satiety mechanism. The effects of different diets have been investigated widely in the cellular mechanisms of the brain, and diets contained a high amount of fat damage to the cellular homeostasis and synaptic plasticity in the brain. However, how the extracellular matrix is modulated by a high-fat diet has not been evaluated enough. In this study, we assessed how lard based high-fat diet affects extracellular matrix proteins and the behavior of mice. For this purpose, male mice fed by the high-fat diet for 8 weeks, and then the behaviors of mice were assessed by the elevated plus-maze, light-dark box test, open field test, novel object recognition test, and rotarod. Then in different regions of the brain, the protein level of Reelin, tenascin C, and neuroligin 2 was evaluated with western blot, and the number of perineuronal nets positive somas was assessed by immunofluorescence staining. Our results reveal that 8 weeks cause the tendency of decrease in memory, and difficulties in learning of mice, and decrease performance in involuntary motor function. Also, changes in the protein amounts and perineuronal nets showed regional differences, and these differences are mostly related to synaptic plasticity and long-term potentiation. In conclusion, the high-fat diet may alter the behavior of mice by affecting the extracellular matrix structure that provides the proper function of the synaptic plasticity.