The Changes Of Red Blood Cell Viscoelasticity And Exercise-induced Hemolysis In 24-hr Ultra-marathoners

Abstract

PURPOSE: To investigate the changes of viscoelastic properties of RBC membrane, a decisive factor of RBC deformability to avoid hemolysis, in male ultra-marathoners after a 24-hr ultra-marathon event. METHODS:19 runners were prospectively recruited into our study. Blood was drawn before and immediately after the 2015 Taipei Ultra-Marathon Festival, Taiwan. Hematological samples were analyzed for hemolysis. Video particle tracking microrheology was used to determine viscoelastic properties of each RBC sample by calculating the dynamic elastic modulus G’(f) and the viscous modulus G”(f) from 0.2 Hz to 100 Hz. RESULTS:The haptoglobin, RBC count, hemoglobin, hematocrit, mean cell hemoglobin and plasma free hemoglobin values of the recruited runners showed a statistically significant drop in the post-race values (Table 1). Blood concentration of reticulocyte was significantly higher at post-race compared with pre-race (Table 1). Most importantly, we discovered that the majority of runners showed a consistent trend in both the dynamic elastic modulus (G’) and the viscous modulus (G”) of RBC membrane before and after running, and interestingly in most of the runners, G’ and G” would either both increase or decrease simultaneously. Changes in hematocrit levels could be significantly correlated to the change in either G’ (p = 0.000; rs = -0.933) or G” (p = 0.047; rs = 0.714). Our finding provides novel insight in mechanistic studies of RBC membrane properties to exercise related hemolysis. CONCLUSIONS:24-hr ultra-marathon running contributes to exercised-induced hemolysis, and is associated with changes in RBC membrane property including elastic modulus (G’) and the viscous modulus (G”).Table 1: Hematological parameters throughout the ultra-marathon race