Salivary Concentrations Of Lipid Peroxidation Products Represent Plasma Concentrations In Athletes Before And After Exercise

Abstract

Many types of muscular exercise promote the production of reactive oxygen species and result in oxidative stress, as evidenced by increased levels of lipid peroxidation products in both blood plasma and saliva. PURPOSE: To assess the agreement between quantitative measurements of lipid peroxidation products in plasma and saliva of athletes at rest and following the Åstrand-Rhyming test. METHODS: 20 elite athletes, aged 18-22 years, participated in the study. Athletes underwent the Åstrand-Rhyming cycle ergometer test. Blood and saliva samples were collected before (pre-exercise) and immediately after the exercise (postexercise). Diene conjugates (DC), triene conjugates (TC) and Schiff bases (SB) were photometrically determined. Optical densities were measured at 220 nm (absorption of isolated double bonds), 232 nm (absorption of DC), 278 nm (absorption of TC), and 400 nm (absorption of SB). Assumption of normality was verified using the Shapiro-Wilk test. Since all data were normally distributed, comparisons were made using paired Student’s t-test. Bland-Altman (B&A) analysis was applied. RESULTS: DC levels were elevated in plasma (0.17 + 0.02 vs. 0.19 + 0.02 a.u., p < 0.001) and saliva (0.17 + 0.02 vs. 0.19 + 0.02 a.u., p < 0.01) in response to exercise, as were the plasmatic (0.12 + 0.04 vs. 0.14 + 0.04 a.u., p < 0.05) and salivary (0.11 + 0.03 vs. 0.14 + 0.03 a.u., p < 0.05) TC concentrations. SB levels were also significantly higher at postexercise compared to pre-exercise in both plasma (21.46 + 4.63 vs. 31.14 + 6.25 a.u., p < 0.001) and saliva (20.83 + 4.06 vs. 30.19 + 6.45 a.u., p < 0.001). The bias calculated for DC (0.005, pre-exercise; 0.004, postexercise), TC (0.002, pre-exercise; 0.004, postexercise) and SB (0.64, pre-exercise; 0.95, postexercise) using the B&A statistics was not significant both at pre-exercise and at postexercise because the line of equality was within the confidence interval of the mean difference. All of the data points lay within the respective agreement limits. CONCLUSIONS: High agreement between quantitative measurements of plasmatic and salivary DC, TC and SB was detected both at rest and following the Åstrand-Rhyming test. Saliva may be considered as an attractive option for identifying exercise-induced oxidative stress in athletes.