• The Korean Journal of Physiology and Pharmacology
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• v.21 no.6
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• pp.633-641
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• 2017

The aim of this study is to investigate the effects of intermittent ladder-climbing exercise training on mitochondrial biogenesis and ER stress of the cardiac muscle in high fat diet-induced obese middle-aged rats. We induced obesity over 6 weeks of period in 40 male Sprague-Dawley rats around 50 weeks old, and were randomly divided into four experimental groups: chow, HFD, exercise+HFD, and exercise+chow. The exercising groups underwent high-intensity intermittent training using a ladder-climbing and weight exercise 3 days/week for a total of 8 weeks. High-fat diet and concurrent exercise resulted in no significant reduction in body weight but caused a significant reduction in visceral fat weight (p<0.05). Expression of $PPAR{\delta}$ increased in the exercise groups and was significantly increased in the high-fat diet+exercise group (p<0.05). Among the ER stress-related proteins, the expression levels of p-PERK and CHOP, related to cardiac muscle damage, were significantly higher in the cardiac muscle of the high-fat diet group (p<0.05), and were significantly reduced by intermittent ladder-climbing exercise training (p<0.05). Specifically, this reduction was greater when the rats underwent exercise after switching back to the chow diet with a reduced caloric intake. Collectively, these results suggest that the combination of intermittent ladder-climbing exercise training and a reduced caloric intake can decrease the levels of ER stress-related proteins that contribute to cardiac muscle damage in obesity and aging. However, additional validation is required to understand the effects of these changes on mitochondrial biogenesis during exercise.

• Journal of the Korean Applied Science and Technology
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• v.37 no.4
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• pp.762-768
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• 2020

This study aimed to investigate the effect of ladder-climbing exercise training on neurobiological markers in the hippocampus of mice with type 2 diabetes (T2DM). Twenty-one C57BL/6 male mice were randomly assigned to the non-diabetic control (NDC, n = 7), diabetic control (DC, n = 7), and diabetic training (DT, n = 7) groups. The DT group performed ladder-climbing training (LCT) five times a week for eight weeks. We measured the levels of hippocampal neurobiological markers (catalase [CAT], brain-derived neurotrophic factor [BDNF], nerve growth factor [NGF], amyloid-beta [Aβ], tau, and CC motif chemokine ligand 11 [CCL11]). The BDNF levels were significantly higher in the DT group than in the DC group (p < 0.05). The Aβ and CCL11 levels were significantly higher in the DC group than in the NDC and DT groups (p < 0.05). The tau levels were significantly higher in the DC group than in the NDC group (p < 0.05). However, there was no significant difference in CAT and NGF levels among the groups (p > 0.05). These results suggest that while T2DM could induce neurodegeneration, LCT may be effective in alleviating neurodegeneration caused by T2DM.

• Journal of Sericultural and Entomological Science
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• v.51 no.2
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• pp.123-129
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• 2013

The purpose of this study is to investigate the effects of supplementation of mulberry powder, mulberry extract and silkworm powder during the 8 weeks of resistance exercise on muscle increase of rats. Fifty males, Sprague-Dawley rat, were randomly divided into 5 groups: CON(control group, n = 10), REG(resistance exercise group, n = 10), MP REG(mulberry powder intake and resistance exercise group, n = 10), ME REG(mulberry extract intake and resistance exercise group, n = 10) and SP REG(silkworm powder intake and resistance exercise group, n = 10). After climbing the ladder without weights during the 1 week of adaptation period, the rats in the resistance exercise group were trained to climb a 0.98-m vertical(80 degree incline) ladder with weights in their tail during 7 weeks(10 times each day, 2 days per week). After exercise, the skeletal muscle was extracted from the flexor hallucis longus. The absolute weight of skeletal muscle was measured by the electronic balance and the relative weight of skeletal muscle about the weight was calculated. The strength and density of legs muscle were analyzed by the computed tomography scan. After 8 weeks of resistance exercise, the absolute weight of skeletal muscle wasn't significant, but it increased in MP REG 8%, ME REG 8% and SP REG 10% compared to REG. The relative weight of skeletal muscle increased significantly in SP REG compared to REG (p < 0.05). Additionally, there was a significant increase of density and strength of the forelegs in SP REG compared to CON (p < 0.05). However, there was no significant increase of density and strength of the hind legs. In conclusion, regular resistance exercise made rats muscle increase and there was more muscle increase effected by providing silkworm.

• Journal of the Korean Applied Science and Technology
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• v.36 no.3
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• pp.876-884
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• 2019

We investigated the effect of moderate- and high-intensity resistance training on hippocampal neurotrophic factors and peripheral CCL11 levels in high-fat diet (HFD)-induced obese mice. C57/black male mice received a 4 weeks diet of normal (control, CON; n = 9) or a high-fat diet (HF; n = 27) to induce obesity. Thereafter, the HF group was subdivided equally into the HF, HF + moderate-intensity exercise (HFME), and HF + high-intensity exercise (HFHE) groups (n = 9, respectively), and mice were subjected to ladder-climbing exercise for 8 weeks. The hippocampal brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) levels were significantly lower in the HF group than in the CON group (p < 0.05). In addition, in the HFME and HFHE groups were significantly higher than in the HF group (p < 0.05). The peripheral CCL11 levels were significantly higher in the HF group than in the CON group (p < 0.05). In addition, in the HFME and HFHE groups were significantly lower than in the HF group (p < 0.05). However, there was no significant difference according to the exercise intensity among the groups. Collectively, these results suggest that obesity can induce down-regulation of neurotrophic factors and inhibition of neurogenesis. In contrast, regardless of exercise intensity, resistance training may have a positive effect on improving brain function by inducing increased expression of neurotrophic factors.

• 한국체육학회지인문사회과학편
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• v.54 no.2
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• pp.431-439
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• 2015

The purpose of this study was to investigate the effects of resistance exercise training and high-protein diet on anabolic factors and insulin resistance of skeletal muscle in sarcopenic obese rats. 50wks of male Sprague-Dawley rats were randomly assigned for 4 groups(Chow, HP, Ex, HPEx) after 6 weeks of high-rat diet induced obesity period. The 8-week of ladder climbing exercise significantly reduced body fat and insulin resistance, significantly increased mTOR activity. However hind limb muscles weight were not changed. When treat with exercise and high-protein diet, body fat and insulin resistance did not improve, but rather the effect of exercise training appeared to be inhibited. Therefore high protein diet for improving the sarcopenic obesity may be need more study about the amount and composition of protein.

• Journal of the Korean Applied Science and Technology
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• v.37 no.3
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• pp.571-581
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• 2020

The purpose of this study was to investigate the effect of endurance and resistance exercise by using different intensity on diabetic-related blood profiles in impaired glucose tolerance mice. 54 C57BL/6 mice were divided into (1) Control group (CO, n=9), (2) impaired glucose tolerance group (IGT, n=9), (3) IGT + 50% of VO_2max endurance exercise group (IGT50A, n=9), (4) IGT + 75% of VO_2max endurance exercise group (IGT75A, n=9), (5) IGT +50% of 1RM resistance exercise group (IGT50R, n=9), 그리고 (6) IGT + 75% of 1RM resistance exercise group (IGT75R, n=9). Endurance exercise program was performed 40 min/day, 5 days a week for 8 weeks on treadmill. Resistance exercise program was consisted in ladder-climbing 8 set/day, 5 days a week for 8 weeks. After completed the exercise program, there was no different insulin level in the groups. The fasting glucose was significantly lower in CO than in other groups, and it was not different among the exercised groups. However, IGT75R was statistically lower than IGT. HOMA-IR was only different between CO and IGT. HbA1c was higher in IGT than in other groups. As compared with exercised groups, IGT 75A was lower than IGT50R. TC was lower in CO than in other groups, but there was no different in TG. Endurance exercise groups showed higher than CO and IGT in HDL-C level. LDL-C was lower in CO than other groups. In addition, IGT75A was lower than IGT and IGT50R in LDL-C level. In conclusion, 75% of 1RM resistance exercise had more positive effect on fasting glucose, and 75% of VO_2max endurance exercise improved HbA1c and LDL-C level. In addition, endurance exercise had more effective in HDL-C improvement as compared with resistance exercise.

• Journal of the Korean Applied Science and Technology
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• v.38 no.3
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• pp.750-761
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• 2021

This study was performed to observe the responses of angiogenesis-related protein expression in skeletal muscle of aged rats by regular resistance exercise training with aerobic exercise. For the purpose of the study, naturally aged SD rats (20-24 months, N=18) were used and divided into control (CON, n=6), resistance exercise (RE, n=6), and resistance + aerobic exercise (RE + AE, n=6) groups. RE group performed 3 sets × 4 exercises each session using a ladder for laboratory animals, and RE +AE group performed 2 sets × 3 times of ladder climbing and additional treadmill running (30 min) each session. After 8 weeks of exercise training, soleus muscle and extensor digitorum longus muscle (EDL) were extracted and used for analysis. Western blot was performed to analyze the expression levels of angiogenesis-related proteins (HIF-1α, VEGF, FLK-1, Ang-1, Ang-2) in skeletal muscle. As a result of the study, the expression of HIF-1α, VEGF, FLK-1, Ang-1, and Ang-2 proteins in soleus muscle (type I muscle) was higher in RE +AE than in CON group, and HIF-1α, VEGF, Ang-1, Ang-2 protein expression of RE group was higher than that of CON group. Furthermore, Ang-2 to Ang-1 ratio of RE + AE group was higher than that of RE group, showing differences by exercise type. In EDL muscle (type II muscle), HIF-1α was increased only by RE group, whereas VEGF and FLK-1 protein expressions were increased in both training types, and no difference was observed between the types of exercise training. In addition, there was no difference in angiopoieitin protein expressions in EDL muscle by exercise training. Therefore, in aging, regular exercise training induces skeletal muscle angiogenic response regardless of exercise type, and in particular, the combination of aerobic exercise with resistance exercise may have an additional positive effect on angiogenesis in type I muscle.

• Journal of the Korean Applied Science and Technology
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• v.36 no.4
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• pp.1108-1118
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• 2019

The purpose of this study was to examine the effects of aerobic and resistance exercise of different intensity on anti-diabetic and lipid profile improvement in type 2 diabetic mice. C57BL/6 mice were divided into six groups (n=8, in each group): normal group (Normal), type 2 diabetes (DM), type 2 diabetes+VO₂max 50% aerobic exercise group (DM50A), type 2 diabetes+VO₂max 75% aerobic exercise group (DM75A), type 2 diabetes+1RM 50% resistance exercise group (DM50R), and type 2 diabetes+1RM 75% resistance group (DM75R). DM50A and DM75A were subjected to treadmill exercise 40 min/day, 5 days/week, during 8 weeks (DM50A, at the speed of 8 m/min for 1-4 weeks and 8~10 m/min for 5-8 weeks; DM75A, 12 m/min for 1-4 weeks and 12~14 m/min for 5-8weeks). DM50R (1RM50%) and DM75R (1RM75%) were subjected to ladder-climbing exercise with weights secured to their tails, 8 set/day, 5 days/week, during 8 weeks. After 8 weeks of exercise, fasting blood glucose and HOMA-IR was significantly lower in DM group than in DM group. HbA1c showed significantly lower DM50R and DM75R groups than DM group. HDL-C showed the highest level in DM75A group and triglyceride was lowest in DM75R group. The cardiovascular risk index was lowest in the Normal and DM75A groups. Therefore, moderate intensity exercise in T2DM mice showed better improvement in blood glucose and insulin resistance control, and moderate intensity aerobic exercise was effective in reducing the cardiovascular risk index by increasing HDL-C levels.

• Journal of the Korean Applied Science and Technology
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• v.37 no.3
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• pp.409-417
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• 2020

The purpose of this study was to investigate the effects of different types of exercise training on ẞ-Amyloid, Brain-Derived Nerurotrophic Factor(BDNF) and cognitive function in mice with Diabetes Mellitus Group(DM.G). 24 male C57BL/6 mice were randomly assigned to the control (C.G. n = 6) and Diabetes Mellitus Group(DM.G. n = 18) groups. After the Diabetes Mellitus induction period, the DM group was subdivided into DM.G. + sedentary (DM.G., n = 6), DM.G. + endurance exercise (A.G, n = 6), and DM.G. + resistance exercise (R.G., n = 6). The A.G. and R.G performed treadmill and ladder climbing exercises 5 times per week for 8 weeks, respectively. After 8 weeks the results are as follows: ẞ-Amyloid showed higher levels of DM.G. than in A.G., R.G., and C.G., but was not statistically significant(p>.05). BDNF was significantly lower in DM.G. than in C.G., A.G., and R.G.(p <0.05). The Y-maze task performance for cognitive function was significantly lower in DM.G. than in C.G., A.G., and R.G.(p <0.05). These results predict that diabetes can negatively affect ẞ-Amyloid, BDNF and cognitive function. It can also be predicted that low-intensity exercise can positively improve ẞ-Amyloid, BDNF and cognitive function regardless of the type of exercise.

• Journal of the Korean Applied Science and Technology
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• v.36 no.3
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• pp.804-812
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• 2019

The purpose of this study was to investigate the effects of different types of exercise training on neurodegeneration and cognitive function in mice with impaired glucose tolerance (IGT). Thirty-six male C57BL/6 mice were randomly assigned to the control (CO, n = 9) and impaired glucose tolerance (IGT, n = 27) groups. The IGT group consumed 45% high fat diet for 4 weeks and received 40 mg/kg of streptozotocin twice in the lower abdomen to induce IGT. After the IGT induction period, the IGT group was subdivided into IGT + sedentary (IGT, n = 9), IGT + endurance exercise (IGTE, n = 9), and IGT + resistance exercise (IGTR, n = 9). The IGTE and IGTR groups performed treadmill and ladder climbing exercises 5 times per week for 8 weeks, respectively. Fasting glucose and glycated hemoglobin (HbA1c) levels were significantly higher in IGT group than in CO, IGTE, and IGTR groups (p < 0.05). HOMA-IR was significantly higher in IGT group than CO group (p < 0.05). Hippocampal catalase (CAT) was significantly lower in IGT group than in CO group (p < 0.05), while beta-amyloid ($A{\beta}$) was significantly higher in IGT group than in CO group (p < 0.05). Hippocampal tau was significantly higher in IGT group than in CO, IGTE, and IGTR groups (p < 0.05). The Y-maze test performance for cognitive function was significantly lower in IGT group than in CO, IGTE, and IGTR groups (p <0.05). These results suggest that IGT induces neurodegeneration and negatively affects cognitive function, while regular exercise may be effective in alleviating neurodegeneration and cognitive decline regardless of exercise type.