Introduction. The development of isometric exercise (IE) protocols for the early rehabilitation of older adults following total hip replacement (THR) and molecular methods for assessing their efficacy was our aim.

Methods. Eight female patients aged 73-77 years were randomized before a THR into two groups of four patients each. During the first 12 days after the THR, the patients performed daily rehabilitation exercises following the standard protocol in the control group and following the standard protocol supplemented with a complex of IE in the experimental group. The clinical parameters of the blood, ESR, CRP, and the concentrations of certain pro-inflammatory interleukins in the blood were evaluated before the THR, as well as 1 day and 12 days after the THR, for each patient. At these times, rectus femoris biopsies of the operated limb were performed in each patient for a transcriptomic analysis.

Results. The indicators of the clinical blood analysis, ESR, muscle injury, and CRP did not reveal any significant difference between the groups. The concentrations of IL-6, IL-8, and IL-1b recovered to the normal range by 12 days after the THR in the experimental group but not in the control group. The transcriptomic analysis of the muscle biopsies revealed significant up-regulation of the processes associated with inflammatory and immune responses as compared to that in the preoperative state in both groups at day 1 and in the control group by 12 days after the THR, while there were no signs of such activation in the experimental group by 12 days after the THR.

Conclusions. The concentrations of IL-6 and IL-8 in the blood, as well as transcriptomic signatures of the processes and signaling pathways associated with inflammatory and immune responses, can be interpreted as molecular indicators of IE's efficacy for the early rehabilitation of older adults after a THR.