High-intensity interval training has a greater effect on reverse cholesterol transport elements compared with moderate-intensity continuous training in obese male rats

Effects of swimming exercise combined with silymarin and vitamin C supplementation on hepatic inflammation, oxidative stress, and histopathology in elderly rats with high-fat diet-induced liver damage

OBJECTIVES

The aim of this study was to demonstrate that swimming exercise combined with silymarin and vitamin C supplementation improves hepatic inflammation, oxidative stress, and liver histopathology in elderly rats with high-fat diet-induced liver damage.

METHODS

Forty elderly male Wistar rats were randomly assigned to five groups (n = 8 in each): a normal diet (control), a high-fat diet (HFD), HFD + silymarin and vitamin C supplementation (HFD+Sup), HFD + swimming exercise (HFD+Exe), and HFD+Sup+Exe group (HFD+Sup+Exe). The non-alcoholic fatty liver model was induced for 6 wk in the HFD groups. After 6 wk of consuming an HFD, a daily supplemental gavage was administered to rats as an intervention along with HFD in the supplement groups for 8 wk. Moreover, rats in the exercise groups were subjected to swimming exercise training 5 d/wk for the same period.

RESULTS

The combination of swimming training and supplementation caused significant decreases in liver inflammatory biomarkers tumor necrosis factor-α and interleukin-1β while increasing total antioxidant capacity and peroxisome proliferator-activated receptor α (P < 0.05).

CONCLUSION

In elderly rats with liver injury caused by an HFD, the combination of exercise and silymarin with vitamin C supplementation effectively reduced oxidative stress, liver inflammation, fat accumulation, and regulated liver enzymes.

Elucidating the primary mechanisms of high-intensity interval training for improved cardiac fitness in obesity

Obesity is a global and rising multifactorial pandemic associated with the emergence of several comorbidities that are risk factors for malignant cardiac remodeling and disease. High-intensity interval training (HIIT) has gained considerable attention due to its favorable outcomes of cardiometabolic health in individuals with overweight or obese. The primary aim of this review is to discuss the fundamental processes through which HIIT improves cardiac impairment in individuals with obesity to develop viable treatments for obesity management. In this review, a multiple database search and collection were conducted from the earliest record to January 2013 for studies included the qualitative component of HIIT intervention in humans and animals with overweight/obesity related to cardiac remodeling and fitness. We attempt to integrate the main mechanisms of HIIT in cardiac remolding improvement in obesity into an overall sequential hypothesis. This work focus on the ameliorative effects of HIIT on obesity-induced cardiac remodeling with respect to potential and pleiotropic mechanisms, including adipose distribution, energy metabolism, inflammatory response, insulin resistance, and related risk profiles in obesity. In conclusion, HIIT has been shown to reduce obesity-induced risks of cardiac remodeling, but the long-term effects of HIIT on obesity-induced cardiac injury and disease are presently unknown. Collective understanding highlights numerous specific research that are needed before the safety and effectiveness of HIIT can be confirmed and widely adopted in patient with obesity.

Skeletal Muscle Mitochondrial and Perilipin Content in a Cohort of Obese Subjects Undergoing Moderate and High Intensity Training

Obesity is a complex condition characterized by abnormal and excessive fat accumulation, resulting in an increased risk for severe health problems. Skeletal muscles play a major role in movement and fat catabolism, but the insulin resistance that comes with obesity makes it difficult to fulfill these tasks. In this study, we analyse two types of training protocols, moderate intensity continuous training (MICT) versus high intensity interval training (HIIT), in a cohort of obese subjects to establish which muscle adaptations favour fat consumption in response to exercise. Mitochondria play a role in fat oxidation. We found protein upregulation of mitochondrial biomarkers, TOMM20 and Cox-4, in HIIT but not in MICT, without detecting any shifts in fibre composition phenotype of the vastus lateralis in both training groups. Interestingly, both MICT and HIIT protocols showed increased protein levels of perilipin PLIN2, which is involved in the delivery and consumption of fats. HIIT also augmented perilipin PLIN5. Perilipins are involved in fat storage in skeletal muscles and their upregulation, along with the analysis of circulatory lipid profiles reported in the present study, suggest important adaptations induced by the two types of training protocols that favour fat consumption and weight loss in obese subjects.

Irisin/FNDC5 influences myogenic markers on skeletal muscle following high and moderate-intensity exercise training in STZ-diabetic rats

In the present study, we investigated the effects of high-intensity interval training (HIIT) versus moderate-intensity continuous training (MICT) on irisin and expression of myogenic markers (paired box 7 (Pax7), myogenic differentiation 1 (MyoD), myogenin) in skeletal muscle of diabetic rats. Eighty-four male Wistar rats (6 weeks of age) were randomly divided into seven groups (n = 12): basic control (Co Basic), 8 weeks control (Co 8w), diabetes mellitus (DM), HIIT, DM + HIIT, MICT, and DM + MICT groups. Diabetes was induced by intraperitoneal injection of streptozotocin (STZ). TheV ˙ o 2 max protocol was characterized by running on a rodent treadmill with moderate intensity (60-70%V ˙ o 2 max ), 60 min per session, 5 days/week, for 6 weeks. HIIT consisted of six 3-min runs at a high intensity (80-90%V ˙ o 2 max ) alternated with 2-min running at low intensity (50%V ˙ o 2 max ), 30 min per session, 5 days/week, for 6 weeks. Results showed that DM decreased myoblast markers compared to Co Basic and Co 8w groups. Fibronectin type III domain-containing protein 5 (FNDC5) mRNA decrease was correlated with myoblast markers (Pax7 r = 0.632, p = 0.027; MyoD r = 0.999, p = 0.001; myogenin r = 1.000, p = 0.001) in DM group. DM + MICT significantly increased gene expression of MyoD, myogenin, and FNDC5 compared to DM and DM + HIIT. The results also showed that the intensity and duration of exercise on the treadmill were effective in stimulating irisin and myogenic markers after DM.

Combined Effects of High-Intensity Aerobic Exercise Training and Ziziphus jujuba Extract on Tissue Nesfatin-1 in Rats

Nesfatin-1 is involved in metabolic/feeding regulation and prevention of cardiovascular disease. Previous studies have shown that exercise and herb supplementation can influence nesfatin-1 concentration. The present study investigated the effects of high-intensity training (HIT) and Ziziphus jujuba (ZJ) extract on tissue nesfatin-1 in rats. Twenty-eight female rats were randomly assigned to one of four groups i.e. 1) Saline-Control (SC), 2) Saline-High Intensity Training (ST), 3) Ziziphus jujuba-Control (ZJC), and 4) Ziziphus jujuba-High Intensity Training (ZJT). Rats performed exercise on a treadmill and/or administered supplements intragastrically for 6 weeks, depending on group category. Seventy-two hours after the last training session, rats were anesthetized. Blood, hypothafi 2lamus tissue, heart and gastrocnemius muscles were sent to the laboratory for analyses. Significantly higher nesfatin-1 gene expression and concentration and ATP concentration were found in trained rat. HIT increased plasma High Density Lipoprotein (HDL) and insulin concentration and reduced plasma Triglyceride (TG) and cortisol. ZJ increased tissue nesftain-1 gene expression and concentration while only increasing heart ATP. The combination of exercise and ZJ showed an additive effect compared to each intervention alone on hypothalamus, heart and gastrocnemius NUCB2 gene expression, heart and gastrocnemius nesfatin-1 concentration, plasma HDL and cortisol concentration. The authors recommend both interventions as a means to improve cardiovascular health in rats with further work needed to confirm similar findings in homo sapiens.

Comparative effects of high-intensity interval training and moderate-intensity continuous training on soleus muscle fibronectin type III domain-containing protein 5, myonectin and glucose transporter type 4 gene expressions: a study on the diabetic rat model

BACKGROUND

The increase in fibronectin type-III domain-containing protein 5 (FNDC5), myonectin, and glucose transporter 4 (GLUT4) leads to a decrease in diabetes; meanwhile, exercise training can affect these factors. The result regarding the comparison between the effect of high-intensity interval training (HIIT) and that of moderate-intensity continuous training (MICT) is confusing. Thus, the present study investigated the comparative effects of HIIT and MICT on soleus muscle FNDC5, myonectin, and GLUT4 gene expressions in the diabetic rat model.

METHODS AND RESULTS

Seventy-two male Wistar rats (weight 200 g ± 20) were randomly and equally assigned to six groups: control-healthy, MICT-healthy, HIIT-healthy, control-diabetes, MICT-diabetes, and HIIT-diabetes. At the first level, Streptozotocin (STZ) was utilized to induce diabetes in rats (at a dose of 55 mg/kg). After that, the training groups performed HIIT and MICT programs on the rodent treadmill for 6 weeks (five-session/week). Twenty-four hours after the last intervention, soleus muscle was removed, and sent to a research facility for future examinations. HIIT and MICT increased the muscle FNDC5, myonectin, and GLUT4 gene expression compared to the control group (P < 0.05). The type of training had no significant effect on the FNDC5 (P > 0.05), while the MICT program induced a greater increase in the myonec ztin and GLUT4 compared to the HIIT program (P < 0.05). Meanwhile, a positive relationship between all variables was observed.

CONCLUSIONS

Exercise training has a beneficial effect on diabetes conditions via the effect of FNDC5, myonectin, and GLUT4. Due to the correlation between myonectin and GLUT4 shown in the present study, physical activity may alter myonectin through its effect on GLUT requiring further investigation by subsequent studies.

Effects of high-intensity interval training and flaxseed oil supplement on learning, memory and immobility: relationship with BDNF and TrkB genes

This study examined the independent and combined effects of high-intensity interval training (HIIT) and flaxseed oil supplementation on cognitive/executive functions in middle-aged rats. Hippocampal neurotropic brain factor (BDNF) and tyrosine kinase receptor B (TrkB) gene expression were also measured. Animals were randomly divided into groups including no exercise control and saline (CS), no exercise control and flaxseed oil supplement (CF), exercise training-and saline (TS) and exercise training and flaxseed oil supplement (TF). The training groups undertook a program of HIIT (10 weeks, five sessions per week) and the supplement groups received flaxseed oil supplement (300 mg/kg). The results showed that HIIT and flaxseed oil supplementation independently had positive effects on memory and learning (P<0.05). HIIT and flaxseed oil independently decreased immobility behaviour and increased hippocampal BDNF and TrkB genes expression (P<0.05). HIIT and flaxseed oil combination had a greater effect on some variables (hippocampal TrkB gene expression, memory and immobility) compared to each intervention alone (P<0.05). In conclusion, HIIT and flaxseed oil can independently improve cognitive/executive functions. In addition, HIIT had a greater positive effect than flaxseed oil supplementation on memory and immobility. The combination of HIIT and flaxseed oil supplement had a more positive effect compared to each intervention alone on memory, and immobility. Hippocampal BDNF gene expression did not significantly differ in the combination or independent groups. Thus, future work is needed on several other genes in different segments of the brain to find the additive-mechanisms involved in memory and immobility regulation and younger and older species of rat should be examined.

Proteomic and Structural Manifestations of Cardiomyopathy in Rat Models of Obesity and Weight Loss

Obesity cardiomyopathy increases the risk of heart failure and death. Obesity is curable, leading to the restoration of the heart phenotype, but it is not clear if there are any after-effects of obesity present after weight loss. We characterize the proteomic landscape of obesity cardiomyopathy with an evaluation of whether the cardiac phenotype is still shaped after weight loss. Cardiomyopathy was validated by cardiac hypertrophy, fibrosis, oversized myocytes, and mTOR upregulation in a rat model of cafeteria diet-induced developmental obesity. By global proteomic techniques (LC-MS/MS) a plethora of molecular changes was observed in the heart and circulation of obese animals, suggesting abnormal utilization of metabolic substrates. This was confirmed by increased levels of cardiac ACSL-1, a key enzyme for fatty acid degradation and decreased GLUT-1, a glucose transporter in obese rats. Calorie restriction and weight loss led to the normalization of the heart's size, but fibrosis was still excessive. The proteomic compositions of cardiac tissue and plasma were different after weight loss as compared to control. In addition to morphological consequences, obesity cardiomyopathy involves many proteomic changes. Weight loss provides for a partial repair of the heart's architecture, but the trace of fibrotic deposition and proteomic alterations may occur.

The effects of exercise training on lipid metabolism and coronary heart disease

Blood lipoproteins are formed by various amounts of cholesterol (C), triglycerides (TGs), phospholipids, and apolipoproteins (Apos). ApoA1 is the major structural protein of high-density lipoprotein (HDL), accounting for ~70% of HDL protein, and mediates many of the antiatherogenic functions of HDL. Conversely, ApoB is the predominant low-density lipoprotein (LDL) Apo and is an indicator of circulating LDL, associated with higher coronary heart disease (CHD) risk. Thus, the ratio of ApoB to ApoA1 (ApoB/ApoA1) is used as a surrogate marker of the risk of CHD related to lipoproteins. Elevated or abnormal levels of lipids and/or lipoproteins in the blood are a significant CHD risk factor, and several studies support the idea that aerobic exercise decreases CHD risk by partially lowering serum TG and LDL-cholesterol (LDL-C) levels and increasing HDL-C levels. Exercise also exerts an effect on HDL-C maturation and composition and on reverse C transport from peripheral cells to the liver to favor its catabolism and excretion. This process prevents atherosclerosis, and several studies showed that exercise training increases heart lipid metabolism and protects against cardiovascular disease. In these and other ways, it more and more appears that regular exercise, nutrition, and strategies to modulate lipid profile should be viewed as an integrated whole. The purpose of this review is to assess the effects of endurance training on the nontraditional lipid biomarkers, including ApoB, ApoA1, and ApoB/ApoA1, in CHD risk.