| 摘要: | Endothelial progenitor cells (EPCs) are derived from bone marrow and have a capacity to differentiate into endothelial cells. A number of studies support that EPCs play an important role in the maintenance and repair of endothelium. In other words, they are one of the major factors in regulating endothelial function. Exercise has been demonstrated to improve endothelial function. Recently, sauna therapy has been investigated as the method to enhance the endothelial function; however, there was no study about the effects of exercise in heat on EPCs. Purpose: This study was designed to investigate the effect of heat and exercise on EPCs. Methods: In order to study a potential link among heat, exercise and EPCs in humans, EPCs were quantified by flow cytometry in 14 healthy volunteers undergoing 4 protocols of conditions; Rest 18, Cycle 18 and Rest 40, Cycle 40; Rest 18,defined as taking a rest during 1hour in cool environment (18℃, 60% humidity), Cycle 18- cycling two bouts of 30 min at 60% of their VO2max with 5min of rest between in cool environment (18℃, 60% humidity) , Rest 40-taking a rest during 1hour in hot environment (40℃, 60% humidity) and Cycle 40, cycling two bouts of 30 min at 60% of their VO2max with 5min of rest between in hot environment (40℃, 60% humidity). The maximum oxygen uptake (VO2max), body composition and physiology questionnaire status was analyzed for the selected subjects prior to the study for 3weeks ago and 14 students were selected as subjects of this study. The subjects were randomly assigned to participate one of 4 conditions. At the beginning and at the end of the each protocol, body composition, blood pressure and heart beat were measured. Venous blood samples were drawn after 10 min from completing condition protocol. Rectal temperature was measured by subject-self before, after 30 min and end of protocol (60 min). Paired t-test and the nonparametric Wilcoxon signed rank test was used to compare difference between before and after intervention. Repeated measures 2-way analysis of variance (ANOVA) was used to exam the differences among the 4 conditions. Results: Rest 18 did not present significant difference. Cycle 18 decreased the EPCs to -1.57±1.45 (p< 0.05). However, Rest 40 and Cycle 40 increased circulating EPCs numbers to 4.21±4.30 and 13.93±12.09 of control levels, respectively. There was no significant difference in resting in cool environment. Conclusion: The results presented heat exposure significantly increased circulating levels of EPCs. Treatment combined the heat and exercise had great effect on EPCs. This study show that heat exposure closely related to endothelial functions. |
