Method for non-invasive assessment of the effect of biologically active substances on the rate of the pH level restoration in the muscle after maximum load using 1H MRS

Abstract

Purpose of the study: To determine the possibility of a non-invasive evaluation of the biologically active substances (BAS) effect on the rate of a pH level restoration in a muscle after a maximum load using 1H magnetic resonance spectroscopy (MRS).Materials and methods. Creatine monohydrate and beta-alanine were taken as tested biologically active substances, used according to the manufacturer's recommendations. At the first stage, calibration curves of a pH dependence on the magnitude of chemical shifts were plotted during assigning 1H spectra of model carnosine dipeptide solutions for non-invasive determination of intramuscular pH. Further experiments were carried out on laboratory animals (mice) using a 9 T NMR spectrometer Bruker Advance III WB 400MHz WB (Bruker, Germany). In experiments on volunteers the functional test pwc170 was used for assessing the ergogenic effects of biologically active substances on rectus quadriceps femoris. The test allows to achieve the level of myocytes cytoplasm acidification with lactate, and the effectiveness of functional biologically active substances on endurance, and also the function of aerobic systems by the muscle pH rate of recovery. Detection was performed using a high-field magnetic resonance imaging scanner (Philips Healthcare, Achieva 3.0T, North Braband, The Netherlands) and two SENSE Flex-L surface ring radiofrequency coils.Results. The effect of oral intake of creatine and beta-alanine on the restoration of rectus quadriceps femoris muscle pH after an acidification of the myocytes cytoplasm with lactate was evaluated using the 1H MRS method. Reproducible results with optimal signal-to-noise ratios and width of carnosine spectral peaks were achieved in volunteers using individual protocols and 1H MRS at 3T in the quadriceps femoris. Animal experiments have highlighted the need to develop and use more accurate techniques for voxel extraction and fat suppression during in vivo 1H spectroscopy to reliably capture the chemical shifts of carnosine peaks.Conclusion. The data obtained using 1H MRS on volunteers allow us to conclude that the developed method makes it possible to non-invasively assess the effect of biologically active substances on the rate of restoration of pH level in a muscle after a critical load in real time in vivo.