Tae-Won Jun

Exercise training improves the antioxidant enzyme activity with no changes of telomere length

The purpose of this study was to determine the changes of both oxidant and antioxidant levels with exercise training in obese middle-aged women. The association between telomere length and oxidative stress with exercise was also examined. Sixteen obese middle-aged women participated in this study. The subjects were randomly divided into exercise group (EX) and control group (CON). EX performed aerobic exercise training for 6 months. DNA was extracted from leukocytes in peripheral blood and their telomere lengths were measured by real time PCR analysis. Long-term exercise training decreased body weight and BMI, and increased VO2 max. Resting levels of erythrocyte glutathione peroxidase activity were higher in EX compared to CON. Superoxide dismutase (SOD) activities were higher after the acute exercise test at mid-intensity in post-exercise training than in the pre-exercise training conditions. The telomere length did not change significantly after the acute exercise test in the pre-exercise training condition in spite of the increased level of malondialdehyde (MDA) as a marker of oxidative stress. In conclusion, antioxidant enzyme activities were increased following long-term exercise training; however, the lengths of telomere in leukocytes were not influenced by both mid-intensity and high intensity of exercise stress.

Effects of postnatal treadmill exercise on apoptotic neuronal cell death and cell proliferation of maternal-separated rat pups.

Early adverse experiences resulting from maternal separation may lead to neuronal cell death and they can eventually cause memory impairment. In this study, we investigated the effects of postnatal treadmill exercise on the long-term memory capability, spatial learning ability, and depressive state, on the 5-hydroxytryptamine (5-HT, serotonin) synthesis and tryptophan hydroxylase (TPH) expression in the dorsal raphe nuclei, and on the apoptosis and cell proliferation in the hippocampal dentate gyrus of rat pups following maternal separation. The rat pups in the maternal separation groups were separated from their respective mothers on the postnatal day 14. The rat pups in the maternal separation group showed depressive state with deceased memory capability and learning ability compared to the rat pups in the maternal care group. Postnatal treadmill exercise increased memory capability and learning ability and alleviated depressive state of the rat pups in the maternal separation group. The 5-HT synthesis and TPH expression in the dorsal raphe nuclei and cell proliferation in the hippocampal dentate gyrus were significantly decreased in the maternal-separated rat pups, and postnatal treadmill exercise increased 5-HT synthesis, the TPH expression, and the cell proliferation. In contrast, apoptotic neuronal cell death in the hippocampal dentate gyrus was significantly increased in the maternal-separated rat pups, and postnatal treadmill exercise suppressed the maternal separation-induced apoptosis. The present results demonstrated that postnatal treadmill exercise alleviated maternal separation-induced depression with decrease of memory capability and learning ability, by suppressing apoptotic neuronal cell death and by enhancing cell proliferation.

Treadmill exercise alleviates short-term memory impairment in 6-hydroxydopamine-induced Parkinson’s rats

Progressive loss of dopaminergic neurons in substantia nigra is a key pathogenesis of Parkinson’s disease. In the present study, we investigated the effects of treadmill exercise on short-term memory, apoptotic dopaminergic neuronal cell death and fiber loss in the nigrostriatum, and cell proliferation in the hippocampal dentate gyrus of Parkinson’s rats. Parkinson’s rats were made by injection of 6-hydroxydopamine (6-OHDA) into the striatum using stereotaxic instrument. Four weeks after 6-OHDA injection, the rats in the 6-OHDA-injection group exhibited significant rotational asymmetry following apomorphine challenge. The rats in the exercise groups were put on the treadmill to run for 30 min once a day for 14 consecutive days starting 4 weeks after 6-OHDA injection. In the present results, extensive degeneration of the dopaminergic neurons in the substantia nigra with loss of dopaminergic fibers in the striatum were produced in the rats without treadmill running, which resulted in short-term memory impairment. However, the rats performing treadmill running for 2 weeks alleviated nigrostriatal dopaminergic cell loss and alleviated short-term memory impairment with increasing cell proliferation in the hippocampal dentate gyrus of Parkinson’s rats. The present results show that treadmill exercise may provide therapeutic value for the Parkinson’s disease.

Physical Activity and Body Mass Index and Their Associations With the Development of Type 2 Diabetes in Korean Men

The authors examined the independent and combined associations of physical activity and obesity with incident type 2 diabetes among 675,496 Korean men from the database of the National Health Insurance Corporation. During an average follow-up of 7.5 years (1996-2005), 52,995 men developed type 2 diabetes. Men with overweight, obese I, and obese II classifications had 1.47, 2.05, and 3.69 times higher risk of type 2 diabetes, respectively, compared with normal weight men, and men with low, medium, and high activity had 5%, 10%, and 9% lower risk of type 2 diabetes, respectively, compared with inactive men after adjustment for confounders and physical activity or body mass index for each other. Overweight and obesity were detrimental within all activity categories, and meeting the activity recommendations (medium and high activity) was beneficial at all body mass index levels. Meeting the activity recommendations appeared to attenuate some negative effects of overweight or obesity, and the increased risk of type 2 diabetes due to inactivity was lower in normal weight men. Both preventing overweight or obesity and increasing physical activity are important to reduce the global epidemic of type 2 diabetes, regardless of body weight and activity levels.

Effects of Exercise on Cyclooxygenase-2 Expression and Nuclear Factor-κB DNA Binding in Human Peripheral Blood Mononuclear Cells

There are multiple lines of compelling evidence supporting the beneficial effect of exercise on the prevention and/or improvement of certain chronic diseases. However, exhaustive or intense exercise causes oxygen free radical generation and oxidative stress, which can lead to injuries and chronic fatigue as well as inflammation. Abnormal upregulation of cyclooxygenase‐2 (COX‐2), a rate‐limiting enzyme in prostaglandin biosynthesis, has been implicated in many inflammation‐associated chronic disorders. Nuclear factor‐κB (NF‐κB) is a major transcription factor involved in regulation of COX‐2 gene expression. To determine whether inflammation induction is dependent on intensity of exercise, COX‐2 expression and NF‐κB activation were adopted as the main targets. Thirteen volunteers who participated in the exercise program were subject to four exercise intensities [40, 60, 80, and 100% of heart rate reserve (HRR)] on a treadmill and to resting conditions. Isolated human peripheral blood mononuclear cells (PBMCs) were collected during the resting state and immediately after exercise and subjected to the electrophoretic mobility gel shift assay and Western blot analysis. As exercise intensity increased, both COX‐2 expression and NF‐κB DNA‐binding activity were enhanced. The expression of IκB kinase α (IKKα) and IκBα were not significantly altered. However, exhaustive/vigorous exercise (100% HRR) could induce the phosphorylation of both IKKα and IκBα. In conclusion, a single bout of exercise induced COX‐2 expression and DNA‐binding activity of NF‐κB in human PBMCs, and both COX‐2 expression and DNA‐binding activity of NF‐κB were dependent on exercise intensity.

The impact of duration of one bout treadmill exercise on cell proliferation and central fatigue in rats.

The purpose of this study was to investigate the impact of the duration-dependence of the one bout treadmill exercise on cell proliferation, stress, and central fatigue in rats. The animals were randomly divided into five groups: the non-exercise group, 1-h exercise group, 2-h exercise group, 4-h exercise group, and 6-h exercise group. The exercise load consisted of running at speed of 13 meters/min with the 0° inclination. Cell proliferation in the hippocampal dentate gyrus was increased in response to one bout moderate treadmill exercise in all exercise groups. But there was no statistical significance between the exercise duration and cell proliferation. The optical density of glucocorticoid (GR)-positive cells in the hippocampal dentate gyrus was not changed by treadmill exercise at any exercise duration. Expressions of serotonin (5-hydroxytryptamine, 5-HT) and tryptophan hyroxylase (TPH) were increased by treadmill exercise only at 6 h duration. It seemed like that there was no additional benefits on cell proliferation over 2 h exercise due to stressful factors with over exercise dose, and there was no change of GR expression due to early assessment point of time. It can be suggested that the one-bout of moderate treadmill exercise increased cell proliferation, but treadmill exercise prolonged to 6 h induced central fatigue in rats.

PAPS Contents Development for Elementary School Students

Korean Students` Physical Fitness Test System, was improved from exercise-related fitness to health-related fitness, it manage the results on the web. This research is one of the practical trial using IT environment for health and fitness improvement, by developing web-based contents. In peer debriefing, 105 contents(health : 6 part 34 contents, exercise : 13 part 71 contents) was designed and realized through analyzing 7th curriculum and 11 domesticinternational contents. The output, have good points, could be used in the class on the web, could be carried out by students in anytime, anywhere. Especially, obese or low fitness children can carry out joyfully. And the contents could be improved on the web. This study is the 1st trial to develop web-based contents, enhancing students` to recognize the importance of health and exercise. If this trial was connected to middle, high school and military, could be contributed in Korean Men`s health management. In the future, application study must be carried-out.

Low-intensity treadmill exercise enhances fast recovery from bupivacaine-induced muscle injury in rats

Background Although bupivacaine has been used to study muscle degeneration and regeneration, the potential enhancement of muscle injury by exercise has not been well examined. The purpose of this study was to determine whether low-intensity treadmill exercise enhances fast recovery from bupivacaine-induced muscle injury and to examine concomitant changes in heat-shock protein 70 (HSP70) expression during regeneration process. Methods In this study, Sprague-Dawley rats were randomly divided into the following four groups: the control group (CON), the sham group (SHAM), the injury group (INJ), and the injury and exercise group (EX) (n = 14 in each group). Expressions of HSP70, inducible nitric oxide synthase (iNOS), and caspase-3 were determined at 1 and 7 days after bupivacaine-induced muscle injury in gastrocnemius. Results Results showed that bupivacaine-induced muscle injury (1 day) significantly increased the expressions of HSP70 and iNOS. At 7 days after the muscle injury, HSP70 expression was higher in the EX group compared with that in the INJ group and elevated level of HSP70 by exercise is concomitant with downregulation of iNOS and the decreased number of caspase-3-positive cells as a marker of apoptosis. Fewer necrosis of myofibers were also found in the EX group compared with the INJ group. Conclusion Our results suggest that low-intensity treadmill exercise may enhance fast recovery from bupivacaine-induced muscle injury in rat partly by HSP70 upregulation.