Effects of different doses of leucine ingestion following eight weeks of resistance exercise on protein synthesis and hypertrophy of skeletal muscle in rats

[Purpose]

This study was designed to determine the appropriate Leucine intake volume to obtain the effects of restoring damaged muscle through the synthesis of muscle proteins to increase skeletal muscle and improve exercise performance, and to achieve enhanced muscle hypertrophy.

[Methods]

To clarify the effects of leucine on skeletal muscle hypertrophy of SD rats, following eight weeks of resistance exercise (climbing ladder), the mass of the FHL (Flexor hallucis longus) was measured after extraction, after which change in the activity of muscle signaling proteins (PKB/Akt, mTOR, p70S6K, 4EBP1) was analyzed.

[Results]

The expressions of PKB/Akt, mTOR and p70S6K were increased in L5 (Leucine 50% administration group) compared with the control group (CON) and exercise group (Ex, exercise training group); EL1 (exercise + 10% leucine administration group) and EL5 (exercise + 50% Leucine administration) also exhibited increased expressions of PKB/Akt, mTOR, and p70S6K, while no difference between EL1 and EL5 were observed. No significant differences in 4EBP1 were found among any of the groups. In addition, there were no differences in FHL mass, while relative mass (FHL/body mass) was increased in the exercise group (Ex, EL1, EL5) compared with the control group. No differences were observed among the exercise groups.

[Conclusion]

The present study demonstrated that the relative body mass was increased in the EX group compared with the CON group, while no significant differences in muscle mass could be found among the groups. Even though some signaling proteins were increased, or some differences existed among groups, there were no differences in muscle mass between the leucine administration and exercise training combined with leucine administration groups in the present study.     

The effect of exercise training and water extract from propolis intake on the antioxidant enzymes activity of skeletal muscle and liver in rat

[Purpose]

In this study, the authors have intended to investigate the effects that the exercise training and the intake of the water extract from propolis have on the activity of antioxidant enzymes.

[Methods]

For this purpose, the exercise training (70% VO₂max treadmill running exercise for 60min)of 5 times per week for six weeks and the intake (50mg/kg/day) of the water extract from propolis were performed by separating the experimental animals (SD rats, n=32) into CON(n=8) group, CON+Ex(n=8), PA(n=8), and PA+Ex(n=8).

[Results]

As a result, the following conclusions were obtained: The concentration of the blood glucose and insulin of the CON+Ex group and PA+Ex group which are the exercise parallel group were significantly decreased in comparison with the control group, whereas if comparing the glycogen concentration in skeletal muscle and liver tissue between the exercise parallel group and the CON group, the former showed significantly high value in comparison with the latter (p < .05). In the case of the activity of the antioxidant enzyme in the skeletal muscle and the liver tissue, the activities of SOD, GPX and CAT in the gastrocnemius muscle tissue of the experimental animals showed significantly high value in PA+Ex group in comparison with other experimental groups (p < .05). In addition, the SOD activity in the liver tissue showed that only PA+Ex group was significantly increased, whereas GDX activity showed significantly higher value in CON+Ex group and PA group than CON group (p < .05). However, the activity of CAT in the liver tissue showed that there is no difference between the experimental groups. As a result that measured the concentration of MDA in order to evaluate the damage level of the tissue by oxygen free radicals, the difference between the groups in the liver tissue was not shown, while it was shown that only PA+Ex group in the skeletal muscle tissue was significantly decreased in comparison with other experimental groups (p < .05).

[Conclusion]

Taken together the above findings, it is considered that the parallel treatment of the exercise training and the water extract from propolis can not only increase the use of glycogen of the skeletal muscle and liver tissue, but also it can give the effect to suppress the creation of active oxygen by inducing the activity of the antioxidant enzyme in the body, and in the future, the possibility as the exercise supplements and the antioxidant of the water-soluble propolis are expected.     

Effect of leucine uptake on hepatic and skeletal muscle gene expression in rats: a microarray analysis

[Purpose]

This study was performed to explore the physiological functions of leucine by exploring genes with leucine-dependent variability using DNA microarray.

[Methods]

Sprague-Dawley rats (n = 20) were separated into a HPD (30% High Protein Diet, n = 10) group and a NPD (0% Non Protein Diet, n = 10) group and fed a protein diet for 2 weeks. At the end of the 2-week period, the rats were fasted for 12-16 hours, further separated into subgroups within the HPD (Saline, n = 5, Leucine, n = 5) and NPD (Saline, n = 5, Leucine, n = 5) groups and administered with a leucine solution. The liver and muscles were harvested after 2 hours for RNA extraction. RNA purification from the isolated muscles and target gene identification using DNA chip were performed. The target gene was determined based on the results of the DNA chip experiment, and mRNA expression of the target gene was analyzed using Real-Time PCR.

[Results]

In the skeletal muscle, 27 genes were upregulated while 52 genes were down regulated after leucine administration in the NPD group. In the liver, 160 genes were up-regulated while 126 were down-regulated. The per2 gene was one of the genes with leucine-dependent induction in muscles and liver.

[Conclusion]

This study was performed to explore the physiological functions of leucine, however, a large number of genes showed variability. Therefore, it was difficult to definitively identify the genes linked with a particular physiological function. Various nutritional effects of leucine were observed. High variability in cytokines, receptors, and various membrane proteins were observed, which suggests that leucine functions as more than a nutrient. The interpretation may depend on investigators’ perspectives, therefore, discussion with relevant experts and the BCAA (Branched-Chain Amino Acids) society may be needed for effective utilization of this data.     

The effect of muscle power training with elastic band on blood glucose,cytokine, and physical function in elderly women with hyperglycemia

[Purpose]

The purpose of this study was to identify the effects of muscle power training with elastic band on body composition, glucose relation factor, and physical function in elderly women with hyperglycemia.

[Methods]

A total of 16 elderly women volunteered to participate in this study as subjects, and they were randomly assigned into one of the following two groups: muscle power training group (MPT: n = 8) and control group (CON: n = 8). The muscle power training group took exercise program using elastic band for 12 weeks, and the other group did not receive any exercise program during the same period. Before and after the experiment, both of the two groups received measurement in body composition (BMI, %Fat, skeletal muscle mass), glucose, cytokine (interleukin 6, adiponectin), and physical function (IPPB, grip strength). With these methods, the following conclusions were achieved.

[Results]

The results showed significant increases in adiponectin (p = 0.006), interleukin 6 (p = 0.018), SPPB (p = 0.024), and grip strength (P=.014). Blood glucose was significantly decreased in exercise group than contruo group.

[Conclusion]

It shows that the muscle power training with elastic band can give positive effects in elderly women with hyperglycemia.     

Antioxidant and antiapoptotic effects of pine needle powder ingestion and endurance training in high cholesterol-fed rats

[Purpose]

Pine needle is a kind of medicinal plant ingested traditionally for a variety of purposes. Therefore, we examined the antioxidant and antiapoptotic capacities of pine needle ingestion in high cholesterol-fed and endurance exercise-trained rats.

[Methods]

Animals were divided into six groups as; CON: normal diet control group; EX: normal diet and exercise training group; HC: high cholesterol diet group; HCE: high cholesterol diet and exercise training group; HCP: high cholesterol and pine needle group; HCPE: high-cholesterol and pine needle diet with exercise training group, respectively. Each group consisted of seven Sprague-Dawley male rats. The swim-training groups, EX, HCE, and HCPE swam in the swim pool 60 min/d and 5 d/week for 5 weeks. During the rearing periods, freeze-dried pine needle powder mix with 5% of the high cholesterol diet was supplied to the HCP and HCPE groups. Gastrocnemius muscle was used as the skeletal muscle. Malondialdehyde (MDA), Mn-containing superoxide dismutase (Mn-SOD), Cu, Zn containing superoxide dismutase (Cu,Zn-SOD), and glutathione peroxidase (GPx) were analyzed for their antioxidant capacities. Finally, p53, Bcl-2 (B-cell lymphoma 2), caspase-3 protein expression was analyzed to determine antiapoptotic ability.

[Results]

MDA showed low content in HCPE compared to the HC. Mn-SOD, Cu,Zn-SOD, and GPx protein expression was significantly increased by pine needle ingestion and/or exercise training. In addition, suppression of p53 protein expression resulted in Bcl-2 increase followed by caspase-3 decrease with/without pine needle ingestion and exercise training.

[Conclusion]

When exercise training in addition to pine needle powder ingestion may be a helpful nutritional regimen to athletes and exercisers.     

Serum levels of appetite-regulating hormones and pro-inflammatory cytokines are ameliorated by a CLA diet and endurance exercise in rats fed a high-fat diet

[Purpose]

This study examined whether conjugated linoleic acid (CLA) supplementation and endurance exercise affect appetite-regulating hormones and pro-inflammatory cytokines in rats.

[Methods]

Seven-week-old male Sprague-Dawley rats were divided randomly into the high-fat diet sedentary group (HS, n=8), the 1.0% CLA supplemented high-fat diet sedentary group (CS, n=8), and the 1.0% CLA supplemented high-fat diet exercise group (CE, n=8). Rats in the CE group swam 60 min/day, 5 days/week for 4 weeks.

[Results]

Leptin and insulin levels in the CS and CE groups were significantly lower than those in the HS group (p<0.001), whereas leptin (p<0.01) and insulin (p<0.05) levels decreased significantly in the CE compared to those in the CS group. Interleukin (IL)-1β (p<0.001) and IL-6 (p<0.01) levels in the CS and CE groups decreased significantly compared to those in the HS group. Leptin (IL-1β: r=0.835, p<0.001), IL-6 (r=0.607, p<0.05), insulin (IL-1β: r=0.797, p<0.01), and IL-6 (r=0.827, p<0.01) levels were positively related with pro-inflammatory cytokine levels.

[Conclusion]

Endurance exercise may play an important role during CLA supplementation of rats on a high-fat diet.     

Exercise Training suppresses vascular fibrosis in aging obesity induced rats

[Purpose]

The aim of this study was to investigate the effects of exercise training (ET) on vascular fibrosis in aging model rats with diet-induced obesity.

[Methods]

Twenty-four male Sprague-Dawley rats were divided into 3 groups: Aging control (A-C), A-C with high fat diet (AHF), AHF with ET (AHF + ET). Aging was induced by D-galactose (D-gal) and obesity was induced by HFD (60% fat) for 9 weeks. The experimental rats performed swimming (60 min/day, 5 days/week) for 8 weeks. All rat aorta samples were harvested for RT-PCR and morphologic analyses.

[Results]

The exercise training significantly decreased levels of AT-1, TGF-ß and Coll-1 gene expression compared to AHF group. The AHF + ET group showed a reduced collagen accumulation in the aorta media compared to AHF group.

[Conclusion]

These results suggest that ET could protect the aging obesity aorta against down-regulation of fibrotic factors (AT-1, TGF-ß and Coll-1 gene) and fibrosis by inhibition of collagen accumulation in the aorta media.     

Effects of treadmill exercise on brain insulin signaling and β-amyloid in intracerebroventricular streptozotocin induced-memory impairment in rats

[Purpose]

The purpose of the study is to explore effect of 6 weeks treadmill exercise on brain insulin signaling and β-amyloid(Aβ).

[Methods]

The rat model of Alzheimer’s disease(AD) used in the present study was induced by the intracerebroventricular(ICV) streptozotocin(STZ). To produce the model of animal with AD, STZ(1.5mg/kg) was injected to a cerebral ventricle of both cerebrums of Sprague-Dawley rat(20 weeks). The experimental animals were divided into ICV-Sham(n=7), ICV-STZ CON(n=7), ICV-STZ EXE(n=7). Treadmill exercise was done for 30 min a day, 5 days a week for 6 weeks. Passive avoidance task was carried out before and after treadmill exercise.

[Results]

The results of this study show that treadmill exercise activated Protein kinase B(AKT)/ Glycogen synthase kinase 3α (GSK3α), possibly via activation of insulin receptor(IR) and insulin receptor substrate(IRS) and reduced Aβ in the brain of ICV-STZ rats. More interestingly, treadmill exercise improved cognitive function of ICV-STZ rats. Finally, physical exercise or physical activity gave positive influences on brain insulin signaling pathway.

[Conclusion]

Therefore, treadmill exercise can be applied to improve AD as preventive and therapeutic method.     

Silkworm pupae powder ingestion increases fat metabolism in swim-trained rats

[Purpose]

Many researchers are trying to solve the metabolic syndrome by utilizing a variety of nutritional control and exercise. Of those, silkworm pupae peptides are known to inhibit the synthesis of fat. Therefore, we examine the effect of fat metabolism by supplying silkworm pupae (SP) for 5-week in swim-trained rats.

[Methods]

Animals were divided into four groups as a group (n = 32) fed a normal diet (CO) with exercise training (CE); a group fed a silkworm pupa diet (SPC) with an exercise training (SPE), respectively.

[Results]

Abdominal fat pads (abdominal and epididymal) weight were lowest in SPE. The serum triglyceride, total cholesterol concentrations were lower in the SP and the SPE. HDL-cholesterol, however, was not different between groups. Liver AMPK (AMP-activated protein kinase) was increased in the CE and the SPE. Liver PPAR-α (Peroxisome proliferator-activated receptor alpha) was increased in the SPC and SPE. L-FABP (liver fatty acids binding protein) was increased by SP ingestion. Liver CPT-1 (carnitine palmitoyltransferase-1) protein expression was increased by exercise training only.

[Conclusion]

In the present study showed that the silkworm pupae intake and/or swimming exercise training activates fat metabolism to reduce the concentration of serum lipids. Thus, the silkworm pupae intake leads to a reduction in fat storage, this is considered to be effective in the inhibition of the metabolic syndrome.     

Effect of energy drink dose on exercise capacity,heart rate recovery and heart rate variability after high-intensity exercise

[Purpose]

The purpose of this research was to investigate the effects of exercise capacity, heart rate recovery and heart rate variability after high-intensity exercise on caffeine concentration of energy drink.

[Methods]

The volunteers for this study were 15 male university student. 15 subjects were taken basic physical examinations such as height, weight and BMI before the experiment. Primary tests were examined of VO₂max per weight of each subjects by graded exercise test using Bruce protocol. Each of five subject was divided 3 groups (CON, ECGⅠ, ECGⅡ) by matched method based on weight and VO₂max per weight what gained of primary test for minimize the differences of exercise capacity and ingestion of each groups. For the secondary tests, the groups of subjects were taken their materials before and after exercise as a blind test. After the ingestion, subjects were experimented on exercise test of VO₂max 80% by treadmill until the all-out. Heart rate was measured by 1minute interval, and respiratory variables were analyzed VO2, VE, VT, RR and so on by automatic respiratory analyzer. And exercise exhaustion time was determined by stopwatch. Moreover, HRV was measured after exercise and recovery 3 min.

[Results]

Among the intake groups, ECGⅡ was showed the longest of exercise exhaustion time more than CON group (p = .05). Result of heart rate during exercise according to intake groups, there was significant differences of each time (p < .001), however, not significant differences of each groups and group verse time (p > .05). Result of RPE during exercise according to intake groups, there was significant differences of each time (p < .001), however, not significant differences of each groups and group verse time (p > .05).

[Conclusion]

In conclusion, EDGⅡ showed the significant increase of exercise exhaustion time more than CON group (p=.05) and not significant differences in HR, RPE, RER, HRV, HRR, blood pressure (p > .05). Therefore, 2.5 mg/kg^-1 ingestion of energy drink might be positive effect to increase exercise performance capacity without side-effect in cardiovascular disease.     

Effects of potato and lotus leaf extract intake on body composition and blood lipid concentration

[Purpose]

The purpose of this study was to investigate the effects of potato and lotus leaf extract intake on body composition, abdominal fat, and blood lipid concentration in female university students.

[Methods]

A total of 19 female university students participated in this 8-week study, and they were randomly assigned into 2 groups; potato and lotus leaf extract (skinny-line) administered group (SKG, n =9) and placebo group (PG, n = 10). The main results of the present study are presented below.

[Results]

1) Body mass index, and percent body fat and abdominal fat in students of the SKG showed a decreasing tendency without significant interaction, 2) total cholesterol (TC), triglyceride (TG), and low density lipoprotein (LDL-C) in students of the SKG showed an averagely decreasing tendency and there was a significant interaction of TC only, 3) high density lipoprotein (HDL-C) in students of the SKG showed an increasing tendency without significant interaction, and 4) Z-score of fatness testing interaction in group × repetition did not show a significant interaction; however, there was a significant interaction of TC in group × repetition. Based on these results, 8-week intake of potato and lotus leaf extract had a positive effect of lowering TC. On the other hand, it had no significant effect on other types of lipids and percent body fat changes.

[Conclusion]

There was a positive tendency of blood lipids in students of the SKG and it seems that potato and lotus leaf extract intake might prevent obesity and improve obesity related syndromes.     

Resistance training inhibits the elevation of skeletal muscle derived-BDNF level concomitant with improvement of muscle strength in zucker diabetic rat

[Purpose]

In the present study, we investigated the effects of 8 weeks of progressive resistance training on the level of skeletal muscle derived BDNF as well as glucose intolerance in Zucker diabetic rats.

[Methods]

Six week-old male Zucker diabetic fatty (ZDF) and Zucker lean control (ZLC) rats were randomly divided into 3 groups: sedentary ZLC (ZLC-Con), sedentary ZDF (ZDF-Con), and exercised ZDF (ZDF-Ex). Progressive resistance training using a ladder and tail weights was performed for 8 weeks (3 days/week).

[Results]

After 8 weeks of resistance training, substantial reduction in body weight was observed in ZDF-Ex compared to ZDF-Con. Though the skeletal muscle volume did not change, grip strength grip strength was significantly higher in ZDF-Ex compared to ZDF-Con. In the soleus, the level of BDNF was increased in ZDF-Con, but was significantly decreased (p<0.05) in ZDF-Ex, showing a training effect. Moreover, we found that there was a negative correlation (r=-0.657; p=0.004) between grip strength and BDNF level whereas there was a positive correlation (r=0.612; p=0.008) between plasma glucose level and BDNF level in skeletal muscle.

[Conclusion]

Based upon our results, we demonstrated that resistance training inhibited the elevation of skeletal muscle derived-BDNF expression concomitant with the improvement of muscle strength in zucker diabetic rats. In addition, muscle-derived BDNF might be a potential mediator for the preventive effect of resistance training on the progress of type 2 diabetes.     

The effect of exercise on expression of myokine and angiogenesis mRNA in skeletal muscle of high fat diet induced obese rat

[Purpose]

The purpose of this study was to investigate the effect of regular treadmill exercise on the mRNA expressions of myokines and angiogenesis factors in the skeletal muscle of obese rats.

[Methods]

Thirty two male Sprague-Dawley rats (4weeks old) were divided into the CO (control) and HF (high fat diet) groups. Obesity was induced in the HF group by consumption of 45% high-fat diet for 15 weeks. These groups were further subdivided into training groups (COT and HFT); the training groups conducted moderate intensity treadmill training for 8 weeks. Soleus muscles were excised and analyzed by real-time quantitative PCR.

[Results]

mRNA expression of myokines, such as PGC-1α, IL-6, and IL-15, in the COT and HFT groups (which conducted regular exercise), were higher as compared with the CO and HF groups (p < 0.05). Also, the levels in the HF group were significantly lower when compared with CO group (p < 0.05). Expression of angiogenesis mRNA, namely mTOR, VEGF, and FLT1, were significantly lower in the HF group, as compared to the CO group (p < 0.05). In addition, COT group had a higher expression of mTORC1, mTORC2, VEGF and FLT mRNA, than the CO group (p < 0.05); the HFT group also had higher expressions of mTOR, VEGF and FLT1 mRNA than the HF group (p < 0.05).

[Conclusion]

These results indicate that mRNA expression of myokines was increased through the activity of muscle contraction, and it also promoted the mRNA expression of angiogenesis due to activation of mTOR. Thus, we conclude that not only under normal health conditions, but in obesity and excess nutritional circumstances also, regular exercise seems to act positively on the glycemic control and insulin sensitivity through the angiogenesis signaling pathway.     

Combined influence of dietary restriction and treadmill running on MCP-1 and the expression of oxidative stress-related mRNA in the adipose tissue in obese mice

[Purpose]

This study suggests that the negative effects of inflammation caused by obesity could be prevented through diet restriction and exercise.

[Methods]

In this study, 44 C57/BL6 male mice at about 4 weeks old (Orient bio, South Korea) were given a high fat diet for 5 weeks to make them obese. To help the mice lose weight, their dietary intake was limited and they were exercised on the treadmill for 8 weeks, and during that period, we analyzed the changes of MCP-1, ERK, Mn-SOD, HIF-1, and NOX in epididymal adipose tissue. There ND control group and obese group with high fat diet (HFD), and it is divided into four groups; HFD-ND-EX group, HFD-ND-nonEX group, HFD-DR-EX group and HFD-DR-nonEX group.

[Results]

During their progress, the mRNA expressions of HIF-1α and ERK2 decreased, as did the expression of MCP-1 contained in the nucleus by suppressing oxygen free radicals, which was observed after the exercise program. However, dietary restriction without exercise training triggered an increase in the mRNA expression of MCP-1.

[Conclusion]

To put this in perspective, combining exercise and dietary intake restriction likely prevented an influx of macrophages by reducing the number of fat cells, whereas only dietary restriction was not effective against reducing inflammation.     

The effects of different exercise modes for preventing endothelial dysfunction of arteries and bone loss in ovariectomized rats

[Purpose]

Several epidemiological studies have demonstrated that there are positive correlations between vascular disorders and bone loss in postmenopausal women. The aim of the present study was to examine the effect of different types of exercise (e.g., climbing and swimming) for preventing endothelial dysfunction of arteries and bone loss in ovariectomized rats.

[Methods]

Twenty Sprague-Dawley female rats were randomly divided into three groups: ovariectomy (OVX) plus treatment with vitamin D₃ and nicotine (VDN) (control rats [Con], n = 7), which is an animal model for endothelial dysfunction and bone loss; voluntary climbing resistance exercise with OVX plus VDN (climbing rats [Clim], n = 6), and swimming exercise with OVX plus VDN (swimming rats [Swim], n = 7). The period of exercise training was 8 weeks.

[Results]

The endothelin-1 (ET-1) protein levels were significantly lower in the Clim and Swim groups than in the Con. The endothelial nitric oxide synthase protein levels were significantly higher in the Swim group than in the Con, but they did not differ between the Clim and Con groups. The cortical bone mineral density in the tibia and breaking energy of the femur were significantly higher in the Clim group than in the Con, but this positive effect was not seen in the Swim group.

[Conclusion]

Voluntary climbing exercise decreased arterial ET-1 protein levels and prevented bone loss in a postmenopause-model rat combining OVX and VDN. Conversely, swimming suppressed endothelial dysfunction of the arteries but did not prevent bone loss. Thus, the type of exercise should be cautiously chosen for enhancing vascular function and bone status, especially in females after menopause.     

Effects of vitamin D supplementation and circuit training on indices of obesity and insulin resistance in T2D and vitamin D deficient elderly women

[Purpose]

The purpose of this study was to investigate the effects of vitamin D supplementation and circuit training on body composition, abdominal fat, blood lipids, and insulin resistance in T2D and vitamin D deficient elderly women.

[Methods]

Fifty-two elderly women were randomly assigned to either the vitamin D supplementation with circuit training group (D+T: n = 15), the circuit training group (T: n = 13), the vitamin D supplementation group (D: n = 11), or the control group (CON: n = 13). The subjects in D took vitamin D supplements at 1,200 IU per day for 12 weeks; the subjects in T exercised 3 to 4 times per week, 25 to 40 minutes per session for 12 weeks; and the subjects in D+T participated in both treatments. Subjects in CON were asked to maintain normal daily life pattern for the duration of the study. Body composition, abdominal fat, blood lipids, and surrogate indices for insulin resistance were measured at pre- and post-test and the data were compared among the four groups and between two tests by utilizing two-way ANOVA with repeated measures. The main results of the present study were as follows:

[Results]

1) Body weight, fat mass, percent body fat, and BMI decreased significantly in T, whereas there were no significant changes in the variables in D and CON. Lean body mass showed no significant changes in all groups. 2) TFA and SFA decreased significantly in T, whereas there were no significant changes in the variables in D and CON. The other abdominal fat related variables showed no significant changes in all groups. 3) TC, TG, HDL-C, and LDL-C showed improvements in T, whereas there were no significant changes in the variables in D and CON. 4) Fasting glucose, fasting insulin, and HOMA-IR tended to be lower in D+T.

[Conclusion]

It was concluded that the 12 weeks of vitamin D supplementation and circuit training would have positive effects on abdominal fat and blood lipid profiles in T2D and vitamin D deficient elderly women. Vitamin D supplementation was especially effective when it was complemented with exercise training.     

Six week swimming followed by acute uptakes of ginsenoside Rg1 may affect aerobic capacity of SD rats

[Purpose]

The purpose of this study is to examine the effects of six-weeks of endurance swim training and short-term intake of Rg1 on the expression of related proteins as well as improvement of aerobic exercise capacity in 8-week-old male SD rats.

[Methods]

The groups were divided into placebo (NP, n=6), Rg1 (NRG, n=6), exercise+placebo (EP, n=7), and exercise+Rg1 (ERG, n=7). On completion of the 6-week swimming exercise, Rg1-intake groups were treated with acute uptakes (3 times within 24hrs) of Rg1. After the treatment, all groups were subjected to a swim to exhaustion test, and then the mass of muscle tissue, mRNA expression level and activity of citrate synthase (CS) were analyzed on plantaris.

[Results]

There were no differences in the effect of 6-week swimming exercise and short-term intake of Rg1 on body weight and muscle mass between groups. Although the CS mRNA expression was elevated in the exercise group and combined treatment group, there was no significant difference in CS activity. Acute uptakes of Rg1 did not affect swimming time to exhaustion, but it was increased by 235% and 314% by the 6-weeks of exercise and combined treatment of exercise and Rg1, respectively, which suggests that the combined treatment increased the effect on the capacity of aerobic exercise.

[Conclusion]

Based on these results, it was confirmed that even a short-term treatment of Rg1 can give an additive effect for improvement of exercise function, and additional studies are needed for the mechanisms and modes of its working.     

Changes of bone metabolism based on the different interventions with exercise type or additional intake material in ovariectomized rats

[Purpose]

This study is aimed at providing clear guidance on treatment and prevention of osteoporosis by comparing and analyzing some well-known methods out of drug and exercise therapies.

[Methods]

For this purpose, eight-week experiments (drug therapy and exercise therapy) were carried out by using rats whose menopause was induced by the removal of an ovary. In the treatment of the drug therapy, the effects of soy protein, one of the well-known alendronate and estrogen replacement therapy, were compared and analyzed. In the treatment of the exercise therapy, endurance exercise using a treadmill and resistance exercise through climbing a special cage were compared and analyzed. Based on these results, this study will be able to suggest the most appropriate way to deal with osteoporosis which requires long-term treatment. Sixty eight-week-old Sprague-Dawley female rats had a week to adapt to the new environment. After that, they were randomly divided into four groups (Sham-Sedentary; SS, ovariectomized-control; OC, ovariectomized-soy protein; OS: ovariectomized-alendronate; OA, ovariectomized-endurance exercise; OE, ovariectomized-resistance exercise; OR) before having an operation for the removal of an ovary. After surgery, the rats convalesced for a week. Alendronate (0.4mg / kg of body weight) and isoflavones (200g / 1 kg of feed) were given to two groups respectively for eight weeks. The rats in the other two groups performed resistance exercise (climbing) and endurance exercise (20 m/min; 60min/day) five days a week for eight weeks.

[Results]

Ovariectomy increased the body weight and body fat like menopause did. Soy protein and alendronate intake for eight weeks had no effect on body weight but reduced the body fat increased by ovariectomy to the level of the SS group. The menopause induced by ovariectomy did not affect total bone density and bone mass as well as bone density in specific areas of the body. Soy protein and alendronate intake for eight weeks did not significantly affect them either. However, the eight-week treatment with soy protein and alendronate significantly reduced the level of osteocalcin in blood. Resistance exercise more noticeably increased body weight and bone mass than running on the low-intensity treadmill but serum osteocalcin levels were notably increased in both cases.

[Conclusion]

These results show that soy protein which is natural produce and low-intensity, regular endurance exercise also have an effect on the treatment and prevention of osteoporosis caused by menopause.     

Inhibition of AMPK expression in skeletal muscle by systemic inflammation in COPD rats

Background

Chronic obstructive pulmonary disease (COPD) is a disease characterized by airflow limitation and inflammation. Meanwhile, COPD also is associated with metabolic disorders, such as skeletal muscle weakness. Strikingly, activation of AMP-activated protein kinase (AMPK) exerts critical roles in energy metabolism. However, it remains unclear whether and how the expression levels of AMPK are affected in the COPD model rats which may lead to the dysfunction of the skeletal muscle in these rats.

Methods

Here we developed a rat model of COPD, and we investigated the morphological changes of peripheral skeletal muscle and measured the levels of tumor necrosis factor -α (TNF-α) and AMPK in skeletal muscle by using approaches that include immunohistochemistry and polymerase chain reaction (PCR).

Results

We found that the expression levels of both AMPK mRNA and protein in skeletal muscles were significantly reduced in the COPD model rats, in comparison to those from the control rats, the COPD model rats that received treatments with AICAR and resveratrol, whereas the expression levels of TNF-α were elevated in COPD rats.

Conclusion

Such findings indicate that AMPK may serve as a target for therapeutic intervention in the treatment of muscle weakness in COPD patients.     

Effect of aerobic exercise training on non-alcoholic fatty liver disease induced by a high fat diet in C57BL/6 mice

[Purpose]

The aim of this study was to investigate the effects of aerobic exercise training on a high fat diet (HFD)-induced fatty liver and its metabolic complications in C57BL/6 mice.

[Methods]

Mice at 5-month old (n = 30) were randomly assigned to standard chow (SC + CON, n = 10) and high-fat diet (HFD, n = 20), and they were subjected to SC and HFD, respectively, for 23-week. After 15-week of HFD, mice in the HFD group were further assigned to HFD (HFD + CON, n = 10) or exercise training (HFD + EX, n = 10) groups. The HFD + EX mice were subjected to aerobic treadmill running during the last 8-week of the 23-week HFD course. Outcomes included hepatic steatosis, insulin resistance, and expression of genes involved in mitochondrial function and/or fatty oxidation as well as de novo lipogenesis and/or triacylglycerol (TAG) synthesis.

[Results]

Treadmill running ameliorated impaired glucose tolerance and insulin resistance secondary to the HFD. The beneficial effects of treadmill running were associated with enhanced molecular markers of mitochondrial function and/or fatty acids oxidation (i.e., PPARα and CPT1a mRNAs, pAMPK/AMPK, pACC, and SIRT1 protein) as well as suppressed expression of de novo lipogenesis and/or TAG synthesis (i.e., SREBP1c, lipin1 and FAS mRNAs) in the liver.

[Conclusion]

The current findings suggest that aerobic exercise training is an effective and non-pharmacological means to combat fatty liver and its metabolic complications in HFD-induced obese mice.