| Summary: | 碩士 === 長庚大學 === 復健科學研究所 === 97 === Abstract
Background and Purpose: Various adaptive immune cell functions are temporarily impaired following acute bouts of intense exercise and severe hypoxia. Conversely, chronic exercise under normoxic condition can reduce the risk of infective disease by improving lymphocyte-related immune function. However, the effect of the hypoxic exercise training on lymphocyte function remains unclear. This study investigates how hypoxic exercise training affects oxidative stress-induced lymphocyte apoptosis and further explores its underlying mechanisms.
Methods: Healthy sedentary young men were trained on a bicycle ergometer, engaging five groups in a normobaric hypoxia chamber: two hypoxic exercise training group (i.e., 15% O2 with 60%VO2max and 60%HRR), hypoxic training group (i.e., 15% O2), exercise training group (60%VO2max), and control group. Duration of training is 30 minutes per day, 5 days per week for 4 weeks. Sublethal oxidative stress was administered by treating the lymphocyte with H2O2, to closely approximate in vivo pro-oxidative conditions. Lymphocyte apoptotic events that included caspase 3, 8 and 9 activation, mitochondrial transmembrane potential (MTP) change and phosphotidyl serine (PS) exposure, as well as the expressions of CD marker on the lymphocytes(CD3, CD4, CD8) that included CD28, CD45RO, CD45RA, CD62L, CD11a, CD57, KLRG1 were evaluated by flow cytometry. Results: Before the training, strenuous, acute exercise enhanced H2O2-induced PS exposure of lymphocyte, which was accompanied by a decline in MTP and an increase in active-form caspase 3, 8 and 9 contents in lymphocyte. Moreover, there is more aged T cell circulating in the peripheral blood stream. However, 4 weeks of hypoxic exercise training attenuated H2O2-induced lymphocyte apoptotic response during strenuous, acute exercise. Furthermore, the expressions of CD marker represent that there will be more activated and less aged T cell circulating in the peripheral blood stream followed by the 4 weeks of the hypoxic exercise training. Although 4 weeks of moderate exercise training recruit more aged T cell, the lymphocyte survival and apoptosis are not affected. After 4 weeks of hypoxia training and control group, there is no difference of lymphocyte apoptosis and the expressions of CD marker.
Conclusion: The regimen of the hypoxic exercise training, moderate exercise training and hypoxia training don’t harm the adapted immune function. There is even an improvement of lymphocyte function by hypoxic exercise training. And choosing the more light dose of the relative workload could achieve the same effect of the absolute workload.
Clinical Relevance: These experimental findings help to determine a hypoxic exercise regimen that modulates lymphocyte function, effectively depress the exercise induced adaptive immunosuppression under oxidative stress.
Key Words: hypoxia, exercise, training, redox status, apoptosis, lymphocyte, phosphatidylserine, mitochondrial transmembrane potential, caspase, thiol, CD marker
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