Effect of L-tryptophan on the bone biophysical properties and oxygen consumption in rats with diet-induced obesity

Abstract

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.