Changes in thioredoxin concentrations: an observation in an ultra-marathon race

Abstract

Objectives: Changes in plasma thioredoxin (TRX) concentrations before, during, and after a 130-km endurance race were measured with the aim of elucidating the relationship between exercise and oxidative stress (OS).

Methods: Blood samples were taken from 18 runners participating in a 2-day-long 130-km ultra-marathon during the 2 days of the race and for 1 week thereafter. There were six sampling time points: at baseline, after the goal had been reached on the first and second day of the endurance race, respectively, and on 1, 3, and 5/6 days post-endurance race. The samples were analyzed for plasma TRX concentrations, platelet count, and blood lipid profiles.

Results: Concentrations of plasma TRX increased from 17.9 ± 1.2 ng/mL (mean ± standard error of the mean) at baseline to 57.3 ± 5.0 ng/mL after the first day's goal had been reached and to 70.1 ± 6.9 ng/mL after the second day's goal had been reached; it then returned to the baseline level 1 day after the race. Platelet counts of 21.3 ± 1.2 × 10(4) cell/μL at baseline increased to 23.9 ± 1.5 × 10(4) cells/μL on Day 1 and to 26.1 ± 1.0 × 10(4) cells/μL on Day 2. On Day 7, the platelet counts had fallen to 22.1 ± 1.2 × 10(4) cell/μL. There was a significant positive correlation between plasma TRX and platelet count.

Conclusions: These data suggest that plasma TRX is an OS marker during physical exercise. Further studies are needed to determine the appropriate level of exercise for the promotion of health.

Fig. 1

Study protocol. Anthropometric measurements and blood samplings were performed at six time points: before the race (baseline), after completing the first stage (DAY 1), after completing the final stage (DAY 2), and 1 day (DAY 3), 3 days (DAY 5), and 5/6 days (DAY 7) after the race

Fig. 2

Changes in plasma thioredoxin (TRX) and platelet counts throughout the study period. Solid line with filled circles Plasma TRX concentrations, dotted line with filled triangles platelet counts. Data are given as the mean ± standard error of the mean (SEM). *p < 0.05 denotes a significant difference from the baseline value

Fig. 3

Correlation between plasma TRX and platelet counts throughout the study period

Fig. 4

Changes in plasma TRX and serum free fatty acids (FFA) concentrations throughout the study period. Solid line with filled circles Plasma TRX concentrations, dotted line with filled triangles plasma FFA levels. Data are expressed as the mean ± SEM. *p < 0.05 denotes a significant difference from the baseline value

Fig. 5

Correlation between plasma TRX levels and log plasma FFA concentrations throughout the study period

Fig. 6

Changes in lipid profiles throughout the study period. Dotted line Serum triglyceride concentrations, solid line total cholesterol concentrations, broken line high-density lipoprotein (HDL)-cholesterol. Data are expressed as the mean ± SEM. *p < 0.05 denotes a significant difference from the baseline value