Neuromotor Activity, Anxiety and Cognitive Function in the In Vivo Model of Alimentary Hyperlipidemia and Obesity

Behavioral indicators characterizing specific features of the pathological process of alimentary-dependent diseases were studied using in vivo model of alimentary hyperlipidemia in rats and mice. Rats and mice of the control groups received balanced semisynthetic diet for 63 days; animals of the experimental groups received a diet with high fat content (30% dry weight), balanced or high-fat diet with fructose solution instead of water, balanced cholesterol-enriched diet (0.5% dry weight), or balanced cholesterol-enriched diet with fructose solution. During the experiment, the mass of food, consumed by the animals, was monitored daily. Muscle tone was assessed by the front paw grip strength on days 33 and 54 of the experiment. Anxiety was tested in the elevated plus maze on days 36 and 57. Behavior and memory were assessed by conditioned passive avoidance reflex on days 39, 40, and 61. A significant increase in muscle tone was revealed on day 54 in rats fed with a balanced diet with fructose, and in mice, that received a similar diet, supplemented with fructose and cholesterol. Anxiety in the second test (day 57) was significantly decreased in rats fed high-fat diet and increased in mice fed high fat diet and high fat diet with fructose. In the second test, additional amount of cholesterol in the diet was the factor that significantly improved both short-term and long-term memory in both species. In mice, in contrast to rats, addition of fructose, including combination with high-fat diet, significantly worsened short-term and long-term memory. Thus, dietary factors, contributing to alimentary dyslipidemia development in rats and mice, can significantly affect the indices of neuromotor activity, anxiety level and cognitive functions, and the nature and direction of these changes are largely species-specific.