The morphofunctional changes of the liver parenchyma of male Wistar rats after administration of L-tryptophan were investigated. Experimental rats in addition to the standard diet received L-tryptophan at a dose of 80 mg/kg. The duration of the experiment was 28 days. Histological preparations were made from liver tissue according to standard methods. Morphometry was performed on digital images using the computer program “Image J”. The activity of hepatic aminotransferases and albumin concentration were determined in serum by biochemical methods; in liver homogenates determined glucose-6-phosphatase activity and triglyceride concentration; in the suspension of hepatocyte mitochondria determined succinate dehydrogenase activity and protein concentration. Multifrequency bioimpedancemetry was used to assess the biophysical properties of the liver. It was found that the administration of L-tryptophan leads to an increase in the nuclear-cytoplasmic ratio (19%), the number of binuclear hepatocytes (81%), and the relative area of the sinusoid (17%). Aspartate aminotransferase activity decreased in serum of experimental rats and albumin concentration increased. In the homogenate of the liver of these animals, the activity of glucose6-phosphatase and the concentration of triglycerides decreased. Succinate dehydrogenase activity and protein concentration in the hepatocyte mitochondrial suspension increased by 35% and 32%, respectively. The method of multifrequency bioimpedancemetry revealed an increase in the ability of the liver tissue of experimental rats to polarize, namely to increases in reactivity. That is, the administration of L-tryptophan is accompanied by the appearance of morphological, biochemical, and biophysical signs of increased synthetic and regenerative activity of the rat liver parenchyma.

The purpose of the study was to evaluate the effect of L-tryptophan on the biophysical properties of bone tissue and oxygen consumption in rats with diet-induced obesity. The study was conducted on 40 male 3-months- aged Wistar rats. The photometric determination of phosphorus and calcium concentration in the femoral bones was conducted. The rate of oxygen consumption was measured according to chronoamperograms. The biophysical properties of femurs were measured by a methodic three-point bending test. It was shown that the content of calcium (by 15%) and phosphorus (by 20%) was significantly higher in the femurs of rats that received L-tryptophan (at a dose of 80 mg/kg per os) for 28 days compared to the control parameters. The rate of oxygen consumption, density and biophysical properties of the femurs did not change. As a result of the consumption for three months of a high-calorie diet (580 kcal/100 g) in experimental rats clear features of obesity evolved. Thus, they had a greater visceral fat mass (by 145%), a visceral fat mass to body weight ratio (by 122%), and an obesity index (by 145%). In rats with alimentary obesity, the calcium and phosphorus content in the femurs was significantly reduced by 28 and 24%, respectively, and the rate of oxygen consumption was 45% lower than in control animals. Femur bearing capacity, strength limit, and stiffness were significantly lower, namely on 23, 11, and 37%, respectively. Administration of L-tryptophan to rats, against the background of consumption of a high-calorie diet, inhibited the development of obesity. Visceral fat mass and its ratio to body weight in this group of rats were 38 and 23% lower, respectively, compared to the obese group. The concentration of calcium (by 32%) and phosphorus (by 25%) and oxygen consumption rates (by 31%) were significantly greater compared to rats fed only the high-calorie diet. Our research shows that the administration of L-tryptophan to obese animals can prevent the development of negative changes in bone tissue.