[Influence of high-fructose diet on fibronectin level in rat blood serum]

In recent years, the consumption of diets containing a large amount of fructose has increased sharply, which is associated with the observed increase in the incidence of obesity, diabetes mellitus, metabolic syndrome, and cardiovascular diseases. Changes in lipid and carbohydrate metabolism due to increased consumption of fructose are one of the causes of destructive processes in the tissues and cells of the organism. Fibronectin, which is an adhesive and regulatory protein of the intercellular matrix, can serve as one of the markers of these processes. The aim of the research was to study the effect of a high-fructose diet on rat serum fibronectin level. Material and methods. The experiment was performed on 50 outbred male rats aged 5-6 months. Rats from the control group (n=25) received a balanced diet of vivarium. Animals of the experimental group (n=25) for 35 days were fed a diet containing 60% fructose, 20% protein, 14% fiber, 6% fat. From the 36th to the 60th day, all rats were fed usual vivarium diet. On the 60th day, the formation of metabolic changes in the long-term period was evaluated. The animals of each group were weighed before and when removed from the experiment on the 21st, 35th and 60th day. Serum was obtained from blood samples collected during decapitation on an empty stomach under short-term ether anesthesia. The concentration of cholesterol, high and low density lipoproteins, triglycerides, glucose, insulin and fibronectin were determined in serum. The atherogenic index and insulin resistance indices were calculated using the corresponding formulas. Results and discussion. The experiment revealed a significant increase in glucose concentration from 6.52±0.35 (in control) to 7.74±0.73, 7.97±1.91 and 7.87±0.65 mmol/l and in insulin level from 1.6±0.6 to 2.3±0.4, 2.6±0.6 and 3.1±0.9 μU/ml on the 21nd, 35th and 60th days of the experiment, respectively, in animals of the experimental group, which is possibly associated with a sharp rise in the concentration of free fatty acids due to the special metabolism of fructose and the occurring oxidative stress, which causes cell damage and the formation of insulin resistance. This is reflected by insulin resistance indices that are different from the control: HOMA by 42.3, 49.2 and 81.3% higher, CARO by 13.3, 16.0 and 28.8% less than the control in the dynamics of the experiment. There was a tendency to an increase in cholesterol level with a significant rise on the 35th day of the experiment by 58.9% relative to the control. A statistically significant increase in the content of low-density lipoproteins was also observed by 158, 141 and 229% compared with the control. Such a rise can be associated with both increased formation of free fatty acids and lipogenetic activity of insulin. In addition, we revealed a significant increase in the content of fibronectin on days 21, 35 and 60 of the experiment, respectively, from 56.5±2.8 (in control) to 74±8.1, 79±3.8 and 98±2.1 μg/ml. Fibronectin plays a significant role in tissue repair processes, providing cell migration and adhesion. Its blood level can correlate with the degree of destructive and reparative processes in the cells of liver and vascular endothelium. Conclusion. A high-fructose diet in rats causes an increase in the studied biochemical parameters of carbohydrate and lipid metabolism, as well as an increase in blood level of the main regulatory protein of the intercellular matrix - fibronectin.