The effects of exercise modalities on adiposity in obese rats

Long-term effects of photobiomodulation therapy on blood pressure in obese rats induced by a high-fat diet

The main cardiovascular disease risk associated with obesity is hypertension. The therapeutic use of photobiomodulation therapy (PBM) is suggested for the treatment of wound healing, osteoarthritis, and arterial diseases. However, few studies have measured how red laser (at 660 nm) acts over hypertension, and any of those studies used experimental obesity model. The aim of the study was an attempt to evaluate the long-term effect of PBM on systolic blood pressure in an animal model of obesity, induced by a high-fat diet (HFD). Our results indicate that PBM carried out 3 days a week was able to prevent the increase in blood pressure (133.75 ± 4.82 mmHg, n = 8) induced by a high-fat diet (150.00 ± 4.57 mmHg, n = 8; p < 0.05), restore nitric oxide levels (control: 31.7 ± 5.5 μM, n = 8; HFD + PBM: 29.9 ± 3.7 μM, n = 8 > HFD: 22.2 ± 2.9 μM, n = 8, p < 0.05), decrease lipoperoxidation (control: 1.65 ± 0.25 nM, n = 8; HFD + PBM: 2.05 ± 0.55 nM, n = 8 < HFD: 3.20 ± 0.47 nM, n = 8; p < 0.05), and improve endothelial function (pD2 control: 7.39 ± 0.08, n = 8 > pD2 HFD + PBM: 7.15 ± 0.07, n = 8 > HFD: 6.94 ± 0.07, n = 8; p < 0.05). Our results indicate that PBM prevents the elevation of blood pressure in an obese animal model by a mechanism that involves improvement of endothelial function through an antioxidant effect.

Influence of obesity on osseointegration of implants with different surface treatments: A preclinical study

OBJECTIVE

The aim of the present study was to evaluate the effect of obesity on the osseointegration of implants with hydrophobic and hydrophilic surfaces.

MATERIALS AND METHODS

Sixty-four male rats were distributed among four experimental groups: H-HB (Healthy/Hydrophobic): healthy animals with hydrophobic implants; H-HL (Healthy/Hydrophilic): healthy animals with hydrophilic implants; O-HB (Obese/Hydrophobic): animals with induced obesity and hydrophobic implants; O-HL (Obese/Hydrophilic): animals with induced obesity and hydrophilic implants. One hundred and twenty-eight implants were installed in the tibiae of the animals bilaterally (64 on the left tibiae and 64 on the right one) after 75 days of a specific diet (standard or high-fat diet) and euthanasia was performed in the experimental periods of 15 and 45 days after implant placement. Bone formation was assessed by biomechanical analysis (on the left tibiae of each animal), and microtomographic and histomorphometric analyses (on the right tibiae of each animal). Statistical analysis was performed using the Shapiro-Wilk test for normality and ANOVA followed by Tukey test to observe whether there was a significant difference between groups (p < 0.05); the t-test was used to compare the animals' body weight.

RESULTS

The biomechanical analysis showed an increase in the removal torque value of animals after 45 days in comparison to after 15 days, with the exception of O-HB groups. The microtomographic analysis demonstrated no significant differences in the mineralized bone tissue volume between the groups. In the histomorphometric analysis, the H-HL/45 day group/period demonstrated higher bone-implant contact, in comparison to H-HL/15 days and the O-HL/45 day group/period showed an increase in bone area between the implant threads, in comparison to O-HL/15 days.

CONCLUSION

In conclusion, obesity does not interfere with the osseointegration of hydrophobic and hydrophilic implants.

Protective Effect of High-Intensity Interval Training (HIIT) and Moderate-Intensity Continuous Training (MICT) against Vascular Dysfunction in Hyperglycemic Rats

Background

Hyperglycemia is a major risk factor for endothelial dysfunction. Endothelial dysfunction is associated with the inability of endothelial cells to maintain homeostasis of the cardiovascular system. Regular exercise may be considered as an effective and low-cost nonpharmacological tool for improving vascular function, though there is no agreement on the best type of exercise.

Objectives

To determine how high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) may prevent endothelial dysfunction under hyperglycemic conditions, and to compare these two interventions.

Method

Twenty-four eight-week-old male Wistar rats were randomly assigned into four groups: healthy nonexercising control (C), hyperglycemic control (HG-C), hyperglycemic + HIIT (HG-IT), and hyperglycemic + MICT (HG-CT). Hyperglycemia was induced by a single injection of streptozotocin. Hyperglycemic animals were subjected to HIIT or MICT protocols six days a week for six weeks. Decapitation was performed the day after the exercise protocols were completed. The ascending aorta (until the abdominal artery) was examined. An enzyme-linked immunosorbent assay (ELISA) was used to measure the glucagon-likepeptide-1 (GLP-1), endothelial nitric oxide synthase (eNOS), and tumor necrosis factor-alpha (TNFα) levels. A colorimetric assay was used to measure superoxide dismutase (SOD) activity and malondialdehyde (MDA) levels. Quantitative real-time polymerase chain reaction (PCR) was used to measure the expression of the receptor for advanced glycation end-products (RAGE) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB). Hematoxylin and eosin (H&E) staining was used to histologically analyze the aortas.

Results

There was a significantly higher level of GLP-1 and lower expression of RAGE, NF-κB, and TNFα in the HG-IT and HG-CT group compared to the HG-C group. Microscopic examination of aortic tissue showed a better tissue arrangement in both treatment groups than in the HG-C group. Except for the MDA level, there were no significant differences in any of the measured parameters between the HG-IT and HG-CT groups.

Conclusion

Under hyperglycemic conditions, both HIIT and MICT have a protective role against endothelial dysfunction.

Improved Electrical Stimulation-Based Exercise Model to Induce Mice Tibialis Anterior Muscle Hypertrophy and Function

Efficient and suitable animal models directed to skeletal muscle hypertrophy are highly needed; nevertheless, the currently available models have limitations, such as restricted hypertrophy outcome and prolonged protocols; thus, additional research is required. In this study, we developed an improved muscle training protocol for mice by directly stimulating the tibialis anterior (TA) muscle motor point using electrical stimulation. C57BL/6 adult male mice were separated into four groups: CTR (control groups for one and two weeks), ES1 (electrical stimulation for one week), and ES2 (electrical stimulation for two weeks). Following muscle training, TA was taken for further examination. The results demonstrated a steady increase in the fiber cross-sectional area as a result of muscle training (ES1, 14.6% and ES2, 28.9%, p < 0.0001). Two weeks of muscle training enhanced muscle mass and maximal tetanic force by 18 (p = 0.0205) and 30%, respectively (p = 0.0260). To assess the tissue remodeling response in this model, we evaluated satellite cell activity and observed an increase in the number of Pax-7-positive nuclei after one and two weeks of muscle training (both >2-fold, p < 0.0001). In addition, we observed an increase in the number of positive nuclei for MyoD after two weeks (2.6-fold, p = 0.0057) without fiber damage. Accordingly, phosphorylation of mTOR and p70 increased following two weeks of muscle training (17%, p = 0.0215 and 66%, p = 0.0364, respectively). The results indicate that this muscle training strategy is appropriate for promoting quick and intense hypertrophy.

Effects of long-term childhood exercise and detraining on lipid accumulation in metabolic-related organs

The preventive effects of regular exercise on obesity-related health problems are carried over to the non-exercise detraining period, even when physical activity decreases with aging. However, it remains unknown whether regular childhood exercises can be carried over to adulthood. Therefore, this study aimed to investigate the effects of long-term childhood exercise and detraining on lipid accumulation in organs to prevent obesity in adulthood. Four-week-old male Otsuka Long-Evans Tokushima Fatty (OLETF) rats were used as obese animals. OLETF rats were allocated into sedentary and exercise groups: exercise from 4- to 12-week-old and detraining from 12- to 20-week-old. At 12-week-old immediately after the exercise period, regular exercise completely inhibited hyperphagia, obesity, enlarged pancreatic islets, lipid accumulation and lobular inflammation in the liver, hypertrophied adipocytes in the white adipose tissue (WAT), and brown adipose tissue (BAT) whitening in OLETF rats. Additionally, exercise attenuated the decrease in the ratio of muscle wet weight to body weight associated with obesity. Decreased food consumption was maintained during the detraining period, which inhibited obesity and diabetes at 20-week-old after the detraining period. Histologically, childhood exercise inhibited the enlargement of pancreatic islets after the detraining period. In addition, inhibition of lipid accumulation was completely maintained in the WAT and BAT after the detraining period. However, the effectiveness was only partially successful in lipid accumulation and inflammation in the liver. The ratio of muscle wet weight to body weight was maintained after detraining. In conclusion, early long-term regular exercise effectively prevents obesity and diabetes in childhood, and its effectiveness can be tracked later in life. The present study suggests the importance of exercise during childhood and adolescence to inhibit hyperphagia-induced lipid accumulation in metabolic-related organs in adulthood despite exercise cessation.

Obesity affects the proteome profile of periodontal ligament submitted to mechanical forces induced by orthodontic tooth movement in rats

The prevalence of obesity has increased significantly worldwide. Therefore, this study aimed to evaluate the influence of obesity on the proteomic profile of periodontal ligament (PDL) tissues of rat first maxillary molars (1 M) submitted to orthodontic tooth movement (OTM). Ten Holtzman rats were distributed into two groups (n = 5): the M group (OTM), and the OM group (obesity induction plus OTM). Obesity was induced by a high-fat diet for the entire experimental periods After that period, the animals were euthanized and the hemimaxillae removed and processed for laser capture microdissection of the PDL tissues of the 1 M. Peptide extracts were obtained and analyzed by LC-MS/MS. Data are available via ProteomeXchange with identifier PXD033647. Out of the 109 proteins with differential abundance, 49 were identified in the OM group, including Vinculin, Cathepsin D, and Osteopontin, which were selected for in situ localization by immunohistochemistry analysis (IHC). Overall, Gene Ontology (GO) analysis indicated that enriched proteins were related to the GO component cellular category. IHC validated the trends for selected proteins. Our study highlights the differences in the PDL proteome profiling of healthy and obese subjects undergoing OTM. These findings may provide valuable information needed to better understand the mechanisms involved in tissue remodeling in obese patients submitted to orthodontic treatment. SIGNIFICANCE: The prevalence of obesity is increasing worldwide. Emerging findings in the field of dentistry suggest that obesity influences the tissues around the teeth, especially those in the periodontal ligament. Therefore, evaluation of the effect of obesity on periodontal tissues remodeling during orthodontic tooth movement is a relevant research topic. To our knowledge, this is the first study to evaluate proteomic changes in periodontal ligament tissue in response to the association between orthodontic tooth movement and obesity. Our study identified a novel protein profile associated with obesity by using laser microdissection and proteomic analysis, providing new information to increase understanding of the mechanisms involved in obese patients undergoing orthodontic treatment which can lead to a more personalized orthodontic treatment approach.

Obesity influences the proteome of periodontal ligament tissues following periodontitis induction in rats

BACKGROUND AND OBJECTIVES

Many studies have been conducted to better understand the molecular mechanism involved with periodontitis progression. There has been growing interest in the potential impact of obesity on periodontitis onset and progression, but the mechanisms involved remain to be elucidated. The present study was designed to determine the impact of obesity on experimentally induced periodontitis in rats and identify novel pathways involved.

METHODS

Sixteen Holtzman rats were distributed into two groups (n = 8): ligature-induced periodontitis (P) and obesity plus ligature-induced periodontitis (OP). Obesity was induced by a high-fat diet for 70 days, whereas periodontitis was induced for 20 days, with a cotton thread placed around the upper first molars bilaterally. Alveolar bone loss was measured by microtomographic analysis and histologically by histometry on the hemimaxillae. The protein composition of the periodontal ligament was evaluated by proteomic analysis.

RESULTS

Data analysis (body weight, adipose tissue weight, and blood test) confirmed obesity induction, whereas bone loss was confirmed by micro-CT and histologic analyses. Proteome analysis from the periodontal ligament tissues (PDL) identified 819 proteins, 53 exclusive to the P group, 28 exclusive to the OP group, and 738 commonly expressed. Validation was performed by immunohistochemistry for selected proteins (spondin1, vinculin, and TRAP).

CONCLUSION

Histologically, it was found that obesity did not significantly affect bone loss resulting from periodontitis. However, the present study's findings indicated that obesity affects the proteome of PDL submitted to experimental periodontitis, allowing for identifying potential targets for personalized approaches.

The Effects of Testosterone Therapy Combined with Swimming Exercise on Adipose Tissue and Biochemical Parameters in Male Obese Wistar Rats

CONTEXT

Exercise and anabolic steroids are anticipated to promote fat mass reduction and so to decrease the number of comorbidities related to excessive weight.

OBJECTIVE

The aim of this study was to verify the influence of aerobic exercise and the use of steroids on the accumulation of adipose tissue and on the biochemical limitations of Wistar rats nourished by a hypercaloric diet.

METHODS

Forty, young male Wistar rats were split into four groups: obese control (n=10), obese under treatment (n=10), obese under aerobic exercise (n=10) and obese under aerobic exercise and treatment (n=10). All animals were fed with a hypercaloric diet and animals under treatment received intramuscular testosterone. Body (weight and visceral fat) and blood (lipidogram, glucose, and liver enzymes) parameters were assessed.

RESULTS

The group treated with aerobic exercise and testosterone revealed a reduction in body weight and visceral, perirenal, retroperitoneal and epididymal fats, accompanied by the blood levels of glucose, lactate, LDL-cholesterol, HDL-cholesterol, and lactate dehydrogenase; following high-intensity physical activity.

CONCLUSION

The results support the theory that the combination of steroids and physical activity reduces the side-effects of androgenic-anabolic hormones and conveys benefits to some constraints.

Therapeutic Efficacy of Aerobic Exercise Training along with Oak Husk Hydroalcoholic Extract for Amelioration of Inflammation in Obese Elderly Male Mice

BACKGROUND

Fibrinogen and interleukin-1β as a proinflammatory cytokine and interleukin-10 and nesfatin-1 as an anti-inflammatory cytokine have an important role in the development and prevention of systemic inflammation and incidence of obesity-induced diseases. Thus, this study is aimed at the interaction effects of aerobic training and oak husk hydroalcoholic extract consumption on plasma levels of fibrinogen, interleukin-1β, nesfatin-1, and interleukin-10 in obese elderly male mice.

MATERIALS AND METHODS

In this experimental study, 40 fat male mice were fed a high-fat diet for 4 weeks to induce obesity, and subsequently, they were divided randomly into four groups: control, supplement, exercise-placebo, and exercise-supplement. The training groups performed aerobic exercise 5 days a week for 6 weeks (approximately 80-75% VOmax 2). The supplement groups received a solution of oak husk hydroalcoholic extract at a dose of 20 milligram per kilogram of body weight for 6 weeks. Blood samples were taken 48 h after the last training session, and the levels of IL-10, fibrinogen, IL-1β, and nesfatin-1 were measured. Data were analyzed using one-way ANOVA and LSD post hoc tests.

RESULTS

The results showed that six-week training and oak husk hydroalcoholic extract consumption significantly increased the levels of IL-10 and nesfatin-1 in experimental groups (P < 0.001). Also, the levels of fibrinogen and IL-1β decreased significantly in training groups. Averages between group variations of all indicators were statistically significant, and they were more meaningfully pronounced in the exercise-supplement group than other groups (P ≤ 0.05).

CONCLUSIONS

Considering the results of the present study, the use of moderate aerobic exercise and oak husk hydroalcoholic extract is recommended to reduce the risk of obesity; it may also have a positive effect on inflammatory factors.

High-Intensity Interval Training Does Not Change Vaspin and Omentin and Does Not Reduce Visceral Adipose Tissue in Obese Rats

This study aimed to determine the expression of omentin and vaspin, inflammatory markers, body composition, and lipid profile in diet-induced obese rats and high-intensity interval training (HIIT). Forty Wistar rats were divided into four groups: untrained normal diet, trained normal diet (T-ND), untrained high-fat diet (Unt-HFD), and trained high-fat diet (T-HFD). For the animals of the Unt-HFD and T-HFD groups, a high-fat diet was offered for 4 weeks. After that, all the animals in the T-ND and T-HFD groups were submitted to HITT, three times per week, for 10 weeks (2 weeks of adaptation and 8 weeks of HIIT). Muscle (gastrocnemius), liver, epididymal adipose tissue, retroperitoneal adipose tissue, visceral adipose tissue (VAT), and serum were collected to analyze TNF-α, IL-6, PCR, IL-8, IL-10, IL-4, vaspin, and omentin. A body composition analysis was performed before adaptation to HIIT protocol and after the last exercise session using dual-energy X-ray absorptiometry. Omentin and vaspin in the VAT were quantified using Western blotting. The results showed that, when fed a high-fat diet, the animals obtained significant gains in body fat and elevated serum concentrations of vaspin and blood triglycerides. The HIIT was able to minimize body fat gain but did not reduce visceral fat despite the increase in maximum exercise capacity. Moreover, there was a reduction in the serum levels of adiponectin, IL-6, and IL-10. Finally, we concluded that, although the training protocol was able to slow down the weight gain of the animals, there was no reduction in visceral fat or an improvement in the inflammatory profile, including no changes in omentin and vaspin.

Effects of obesity on periodontal tissue remodeling during orthodontic movement

INTRODUCTION

Orthodontic movement triggers a sequence of cellular and molecular events that may be affected by different systemic conditions. This study evaluated the effect of obesity on rat periodontal tissue remodeling induced by mechanical orthodontic force.

METHODS

Thirty-two Holtzman rats were distributed into 4 groups: control, obesity induction (O), orthodontic movement (M), and obesity induction and orthodontic movement (OM). Obesity was induced by a high-fat diet for 90 days. After 15 days of orthodontic movement, the animals were killed. Obesity induction was confirmed by animal body weight, adipose tissue weight, and serologic analysis. Periodontal tissue remodeling was evaluated using microcomputed tomography and histologic analysis. The gene expression of adipokines and cytokines in gingival tissues was evaluated.

RESULTS

An increase in body and adipose tissue weight was observed in the obesity induction groups. The O group presented an increase in lipids and blood glucose. The OM group showed a decrease in bone volume fraction and bone mineral density compared with all other groups and a tendency for more rapid tooth movement than the M group. The OM group showed a higher quantity of inflammatory cells and higher Mmp1 expression than the O group. The O and OM groups showed higher Nampt expression than the control group and lower Nampt expression than the M group.

CONCLUSIONS

Obesity modulates periodontal tissue remodeling during orthodontic movement and results in more inflammation and bone loss than in nonobese animals.

Efficacy of choline and DHA supplements or enriched environment exposure during early adult obesity in mitigating its adverse impact through aging in rats

Introduction

The aim of this study was to assess the efficacy of choline and DHA or exposure to environmental enrichment in obese adult and aging rats on alterations in body mass index, serum lipid profile and arterial wall changes, despite stopping high fat diet consumption and interventions during adulthood.

Methods

21 day old male Sprague Dawley rats were assigned as Experiment-1 & 2 - PND rats were divided into 4 groups with interventions for 7 months (n = 8/group). NC- Normal control fed normal chow diet; OB- Obese group, fed high fat diet; OB + CHO + DHA- fed high fat diet and oral supplementation of choline, DHA. OB + EE- fed high fat diet along with exposure to enriched environment .Experiment-2 had similar groups and interventions as experiment 1 but for next 5 months were fed normal chow diet without any interventions. Body mass index was assessed and blood was analyzed for serum lipid profile. Common Carotid Artery (CCA) was processed for Haematoxylin and eosin, Verhoff Vangeison stains. Images of tissue sections were analyzed and quantified using image J and tissue quant software.

Results

In experiment.1, mean body mass index (p < 0.001), serum lipid profile (p < 0.01), thickness of tunica intima (p < 0.05), tunica media (p < 0.01) and percentage of collagen fibers (p < 0.01) of CCA were significantly increased in OB compared to NC. These were significantly attenuated in OB + CHO + DHA and OB + EE compared to OB. In experiment.2, mean body mass index (p < 0.01), serum lipid profile (p < 0.05) and thickness of tunica media of CCA (p < 0.01) were significantly increased in OB compared to NC. In OB + CHO + DHA and OB + EE, significant attenuation was observed in mean body mass index and mean thickness of tunica media compared to same in OB.

Conclusion

Adult obesity has negative impact on body mass index, serum lipid profile and arterial wall structure that persists through aging. Supplementation of choline and DHA or exposure to enriched environment during obesity attenuates these negative impacts through aging.

Behavioral, cardiovascular and endocrine alterations induced by chronic stress in rats fed a high-fat diet

Chronic stress is a risk factor for cardiovascular diseases (CVD) and anxiety disorders (AD). Obesity also increases the risk of CVD and AD. The modern lifestyle commonly includes high-fat diet (HFD) intake and daily exposure to stressful events. However, it is not completely understood whether chronic stress exacerbates HFD-induced behavioral and physiological changes. Thus, this study aimed to evaluate the effects of the exposure to chronic variable stress (CVS) on behavioral, cardiovascular, and endocrine parameters in rats fed an HFD. Male Wistar rats were divided into four groups: control-standard chow diet (control-SD), control-HFD, CVS-SD, and CVS-HFD. The control-HFD and CVS-HFD groups were fed with HFD for six weeks. The CVS-HFD and CVS-SD groups were exposed to a CVS protocol in the last ten days of the six weeks. The behavioral analysis revealed that CVS decreased the open-arm exploration time during the elevated plus-maze test (p < 0.05). HFD promoted metabolic disorders and increased angiotensin II and leptin blood levels (p < 0.05). CVS or HFD increased blood pressure and the sympathetic nervous system (SNS) modulation of the heart and vessels and decreased baroreflex activity (p < 0.05). Combining CVS and HFD exacerbated the cardiac SNS response and increased basal heart rate (HR) (p < 0.05). CVS or HFD did not affect vascular function and aorta nitrate (p > 0.05). Taken together, these data indicate a synergism between HFD and CVS on the HR and cardiac SNS responses, suggesting an increased cardiovascular risk. Besides, neuroendocrine and anxiogenic disturbers may contribute to the cardiovascular changes induced by HFD and CVS, respectively.

Effects of Aerobic Exercise Protocol on Genes Related to Insulin Resistance and Inflammation in the Pancreas of ob/ob Mice with NAFLD

Purpose

To evaluate the effect of 8 weeks of aerobic training on insulin resistance and inflammatory response in obese mice (ob/ob) with NAFLD.

Materials and Methods

Male ob/ob mice were randomly divided into sedentary (n=7) and trained (n=7) groups. Aerobic training consisted of 5 weekly sessions, 60 min per session at 60% of the maximum speed of the running test. Hepatic and pancreatic samples were collected to evaluate histological features and gene expression associated with insulin resistance and inflammatory response after 8-week experiment protocol. RNA was performed by TRIzol^®. PCR experiments were performed using the Rotor-Gene RG-3000. Parametric data were assessed by t-test, one-way ANOVA and Bonferroni test for multiple comparisons. Non-parametric data were assessed by the Mann-Whitney tests with Dunn's post-test of multiple comparisons. Histological analysis was assessed by chi-square test with Fisher's exact test. Significant variables were considered when p<0.05. All the analyses were performed by GraphPad Prism V6.0 software (GraphPad Software Inc.).

Results

Reductions in bodyweight (p = 0.008), weight evolution (p = 0.03), food intake (p <0.0001) and fat content were observed in trained group. Moreover, the trained group showed better results in peak velocity (p=0.03) physical effort tolerance (p=0.006) and distance (p=0.01). Gene expression showed differences in IL-10 (p=0.03) and GLUT-2 (p=0.03) in hepatic analysis, between groups. Pancreatic gene expression showed difference between groups in IRS-2 (p=0.004), GLUT-2 (p=0.03) and IL-10 (p=0.008) analysis. Also, the trained group showed lower values for interlobular fat and inflammatory infiltrate in histological analysis when compared to sedentary animals.

Conclusion

An 8-week physical training protocol was able to attenuate bodyweight gain, food intake and generate positive effects on gene expression related to insulin resistance and inflammation in both liver and pancreas of ob/ob mice.

Hippocampal neural cell degeneration and memory deficit in high-fat diet-induced postnatal obese rats- exploring the comparable benefits of choline and DHA or environmental enrichment

Purpose: Childhood obesity increases risk for neural dysfunctions causing learning and memory deficits. The objective of the study is to identify the effects of high fat diet-induced obesity in postnatal period on serum lipids, memory and neural cell survival in hippocampus and compare the role of choline and DHA or environmental enrichment in attenuating the alterationsMaterials and methods: 21 day postnatal male Sprague Dawley rats were assigned as Normal control [NC] fed normal chow diet, Obesity-induced [OB] fed high fat diet, Obesity-induced fed choline & DHA [OB + CHO + DHA], Obesity-induced environmental enrichment [OB + EE] [n = 8/group]. Memory was assessed using radial arm maze. Subsequently blood was collected for serum lipid analysis and rats were euthanized. 5 µm hippocampal sections were processed for cresyl-violet stain. Surviving neural cells were counted using 100 µm scale.Results: Memory errors were significantly higher [p < 0.001, 0.01] in OB compared to same in NC rats. Mean number of surviving neural cells in hippocampus of OB was significantly lesser [p < 0.01] compared to same in NC. Interventions in OB + CHO + DHA and OB + EE significantly attenuated [p < 0.01] memory errors and number of surviving neural cells in hippocampus [CA1, CA3 and DG] compared to same in OB. Moreover, hippocampal neural cell survival was found to be inversely related to serum lipid profile in OB group and was attenuated in OB + CHO + DHA and OB + EE rats.Conclusions: High fat diet-induced postnatal obesity in rats causes CA1/CA3 hippocampal neuro-degeneration and memory deficits. Supplementation of choline and DHA in obese rats attenuates these deficits.

Resistance training promotes reduction in Visceral Adiposity without improvements in Cardiomyocyte Contractility and Calcium handling in Obese Rats

Resistance training (RT) improves the cardiomyocyte calcium (Ca²⁺) cycling during excitation-contraction coupling. However, the role of RT in cardiomyocyte contractile function associated with Ca²⁺ handling in obesity is unclear. Wistar rats were distributed into four groups: control, sedentary obese, control plus RT, and obesity plus RT. The 10-wk RT protocol was used (4-5 vertical ladder climbs, 60-second interval, 3× a week, 50-100% of maximum load). Metabolic, hormonal, cardiovascular and biochemical parameters were determined. Reduced leptin levels, epididymal, retroperitoneal and visceral fat pads, lower body fat, and adiposity index were observed in RT. Obesity promoted elevation of collagen, but RT did not promote modifications of LV collagen in ObRT. RT induced elevation in maximum rates of contraction and relaxation, and reduction of time to 50% relaxation. ObRT group did not present improvement in the cardiomyocyte contractile function in comparison to Ob group. Reduced cardiac PLB serine¹⁶ phosphorylation (pPLB Ser¹⁶) and pPLB Ser¹⁶/PLB ratio with no alterations in sarcoplasmic reticulum Ca²⁺ ATPase (SERCA2a) and phospholamban (PLB) expression were observed in Ob groups. Resistance training improved body composition reduced fat pads and plasma leptin levels but did not promote positive alterations in cardiomyocyte contractile function, Ca²⁺ handling and phospholamban phosphorylation.

Muscular resistance, hypertrophy and strength training equally reduce adiposity, inflammation and insulin resistance in mice with diet-induced obesity

Objective

To evaluate the effect of three types of muscular resistance training on adiposity, inflammation levels and insulin activity in Swiss mice with fat-rich diet-induced obesity.

Methods

Lean and obese male Swiss mice were selected and allocated to one of eight groups comprising eight mice each, as follows: standard diet + no training; standard diet + muscular resistance training; standard diet + hypertrophy training; standard diet + strength training; high-fat diet + no training; high-fat diet + muscular resistance training; high-fat diet + hypertrophy training; high-fat diet + strength training. The training protocol consisted of stair climbing for a 10-week period. Blood samples were collected for lactate analysis, glucose level measurement and insulin tolerance test. After euthanasia, adipose tissues were removed and weighed for adiposity index determination. Fragments of epididymal adipose tissue were then embedded for histological analysis or homogenized for tumor necrosis factor alpha level determination using the ELISA method.

Results

Ausency of differences in total training volume and blood lactate levels overall emphasize the similarity between the different resistance training protocols. Body weight loss, reduced adipocyte area and lower adiposity index were observed in trained obese mice, regardless of training modality. Different training protocols also improved insulin sensitivity and reduced inflammation levels.

Conclusion

Resistance training protocols were equally effective in reducing body fat, inflammation levels and insulin resistance in obese mice.

Importance of AT1 and AT2 receptors in the nucleus of the solitary tract in cardiovascular responses induced by a high-fat diet

A high-fat diet (HFD) induces an increase in arterial pressure and a decrease in baroreflex function, which may be associated with increased expression of angiotensin type 1 receptor (AT1R) and pro-inflammatory cytokine genes and reduced expression of the angiotensin type 2 receptor (AT2R) gene within the nucleus of the solitary tract (NTS), a key area of the brainstem involved in cardiovascular control. Thus, in the present study, we evaluated the changes in arterial pressure and gene expression of components of the renin-angiotensin system (RAS) and neuroinflammatory markers in the NTS of rats fed a HFD and treated with either an AT1R blocker or with virus-mediated AT2R overexpression in the NTS. Male Holtzman rats (300-320 g) were fed either a standard rat chow diet (SD) or HFD for 6 weeks before commencing the tests. AT1R blockade in the NTS of HFD-fed rats attenuated the increase in arterial pressure and the impairment of reflex bradycardia, whereas AT2R overexpression in the NTS only improved the baroreflex function. The HFD also increased the hypertensive and decreased the protective axis of the RAS and was associated with neuroinflammation within the NTS. The expression of angiotensin-converting enzyme and neuroinflammatory components, but not AT1R, in the NTS was reduced by AT2R overexpression in this site. Based on these data, AT1R and AT2R in the NTS are differentially involved in the cardiovascular changes induced by a HFD. Chronic inflammation and changes in the RAS in the NTS may also account for the cardiovascular responses observed in HFD-fed rats.

Exercise and Omentin: Their Role in the Crosstalk Between Muscle and Adipose Tissues in Type 2 Diabetes Mellitus Rat Models

This study aims to analyze the effects of resisted, aerobic, and combined exercises on omentin levels in visceral adipose tissue and muscle of rats with experimental diabetes to verify whether these adipokines are related to the glucose pathway and inflammation process in this model. Male Wistar rats received a high-fat diet for 4 weeks and a low dose of streptozotocin (35 mg/kg) to induce experimental diabetes. After inducing diabetes, the animals were divided into 4 experimental groups (n = 10): diabetic control (C); resistance training (RT); aerobic training (AT); and combined training (CT). The groups were exercised for 12 weeks, 3 times/week, where: RT means the stair climbing protocol until exhaustion; AT is the 30 min/day reaching 20 m/min protocol, and CT is the combination of RT and AT. The AT group showed reduced retroperitoneal and mesenteric adipose tissue and abdominal fat deposits. Our study also showed a possible control of blood glucose, as well as decreased Interleukin 6 (IL-6) and C-reactive protein, increased circulating adiponectin and increased omentin in visceral adipose tissue. In addition, the AT group affected the glucose pathway by stimulating phosphorylation of Akt in muscle tissue. Omentin also showed a strong positive correlation with adiponectin and a moderate negative correlation with IL-6. Thus, our findings indicated that omentin in type 2 diabetes is changed by AT. Furthermore, increased omentin levels had a close association with the glucose pathway by stimulating phosphorylation of Akt in muscle tissue and with IL-6 in serum, suggesting that omentin is likely to have anti-inflammatory and protective action in experimental diabetes.

High-fat diet increases respiratory frequency and abdominal expiratory motor activity during hypercapnia

Breathing disorders are commonly observed in association with obesity. Here we tested whether high-fat diet (HFD) impairs the chemoreflex ventilatory response. Male Holtzman rats (300-320 g) were fed with standard chow diet (SD) or HFD for 12 weeks. Then, tidal volume (VT), respiratory frequency (fR) and pulmonary ventilation (VE) were determined in conscious rats during basal condition, hypercapnia (7% or 10% CO2) or hypoxia (7% O2). The mean arterial pressure (MAP), heart rate (HR) and baroreflex sensitivity were also evaluated in conscious rats. A group of anesthetized rats was used for the measurements of the activity of inspiratory (diaphragm) and expiratory (abdominal) muscles under the same gas conditions. Baseline fR, VT and VE were similar between SD and HFD rats. During hypercapnia, the increase of fR was exacerbated in conscious HFD rats (60 ± 3, vs. SD: 47 ± 3 Δ breaths.min-1, P < 0.05). In anesthetized rats, hypercapnia strongly increased abdominal muscle activity in HFD group (238 ± 27, vs. basal condition: 100 ± 0.3%; P < 0.05), without significant change in SD group (129 ± 2.1, vs. basal condition: 100 ± 0.8%; P = 0.34). The ventilatory responses to hypoxia were similar between groups. In conscious HFD rats, MAP and HR were elevated and the baroreflex function was impaired (P < 0.05). These data demonstrated that 12 weeks of HFD exaggerate the ventilatory response activated by hypercapnia. The mechanisms involved in these responses need more investigation in future studies.

Improvement of microvascular endothelial dysfunction induced by exercise and diet is associated with microRNA-126 in obese adolescents

OBJECTIVE

Microvascular endothelial dysfunction, which is at the early stage of atherosclerosis, precedes macrovascular endothelial dysfunction. The study is aimed to investigate the mechanism underlying the improvement of microvascular endothelial dysfunction by exercise and diet in obese adolescents.

METHODS

A quasi-randomized study was carried out with 2 cohorts: the experimental group (57 obese male adolescents; age: 15.38 ± 2.82 years, BMI: 33.21 ± 4.23 kg/m²) completed a 6-week exercise program with dietary intervention, and control group (10 normal weight adolescents; age: 15.38 ± 2.82 years, BMI: 23.21 ± 4.23 kg/m²) maintained sedentary. Clinical characteristics, circulating NO, ET-1 and microRNA-126 (miR-126) levels were measured before and after 6 weeks. The Reactive Hyperemia Index (RHI) was measured using EndoPAT-2000 system.

RESULTS

After 6-weeks intervention, obese adolescents' body circumferences and glucolipid metabolism are significantly improved. RHI (p < 0.01) and serum levels of NO/ET-1 (p < 0.01) are significantly increased, while microRNA-126 significantly decreased (p < 0.01). ΔMiR-126 were positive correlated with ΔBMI (r = 0.60, p < 0.01), ΔRHI (r = 0.69, p < 0.05), and ΔNO/ET-1 (r = -0.68, p < 0.05).

CONCLUSIONS

Combination of exercise and diet control can effectively improve glycolipid metabolism of obese adolescents, and thus their microvascular endothelial function, which might be related to changes in serum miRNA-126.

The Effect of Treadmill Treatment on Oxidative Stress Markers and Endogenous Antioxidant Status in Obesity Mice

AIM:

This study aimed to determine the effect of treadmill treatment on oxidative stress markers and endogenous antioxidant status seen from MDA, GSH, MnSOD enzyme specific activity and blood catalase of obese mice.

MATERIALS AND METHODS:

This research is experimental laboratory research using post-test control design group only. The study lasted for 28 days and was divided into 4 groups of study, i.e., group K (normal control), KP (obesity control), P1 (obesity mice with 1 x 10-minute treadmill treatment a day), and P2 (obesity mice with 2 x 10-minute treadmill treatment a day).

RESULTS:

The treadmill treatment had an effect on the improvement of the oxidative status of mice with a decrease of MDA level of obesity mice blood (p ≤ 0.05) compared to KP control. An elevated endogenous antioxidant status of obesity mice was seen from elevated GSH levels, MnSOD specific activity and blood catalase of obesity mice (p ≤ 0.05) compared with KP controls. Treatment of 1 x 10-minute treadmill per day decreased blood MDA level, increased GSH enzyme and increased specific activity of MnSOD enzyme and blood catalase of obese mice.

CONCLUSIONS:

The 2 x 10-minute daily treadmill did not differ significantly in improving the oxidative status and endogenous antioxidant status compared with the treadmill 1 x 10 minutes a day (p ≥ 0.05).

High-fat diet leads to adiposity and adipose tissue inflammation: the effect of whey protein supplementation and aerobic exercise training

There is little understanding about dietary proteins and their potential contribution to obesity-induced inflammation. This study investigates the effect of 10 weeks of aerobic training and whey protein (WP) supplementation on visceral adipose tissue inflammation in rats fed a high-fat diet (HFD). In the first phase, which lasted 9 weeks, 40 male Wistar rats were randomly divided into 2 groups: (1) normal diet (n = 8), and (2) HFD (n = 32). In the second phase, rats fed an HFD were randomly assigned into 4 groups (n = 8/group): (1) sedentary, (2) WP, (3) aerobic training, and (4) WP + aerobic training. The aerobic training was performed for 10 weeks, 5 days/week at 21 m/min, 15% incline, for 60 min/day. HFD significantly increased body weight, adiposity index, fat pads weight, glucose levels, and insulin resistance index compared with the normal diet. Also, levels of tumor necrosis factor alpha (TNF-α), monocyte chemoattractant protein-1 (MCP-1), hypoxia inducible factor 1 alpha (HIF-1α), and vascular endothelial growth factor A (VEGF-A) in adipose tissue and serum levels of TNF-α were increased in the HFD group. Glucose levels, insulin resistance index, and triglycerides were reduced only by WP, independently of aerobic training. Both the aerobic training and WP reduced the fat pads weight and levels of TNF-α, HIF-1α, and VEGF-A in adipose tissue. Nevertheless, the levels of MCP-1 in adipose tissue and serum levels of TNF-α and MCP-1 were not reduced significantly by WP or aerobic training. These findings suggest that both aerobic training and WP supplementation lead to a reduction in adiposity and ameliorate obesity-induced inflammation in visceral adipose tissue.

Intermittent resistance exercise and obesity, considered separately or combined, impair spermatic parameters in adult male Wistar rats

Obesity and absence of physical exercise are global problems that affect concentration and sperm quality in the male reproductive system. The purpose of this study was to examine the effect of obesity and resistance training, considered separately or in association, on testicular function and reproductive capacity. Twenty pubertal male Wistar rats were distributed into four groups: control (C) and exercise (E) groups that received standard rat chow; and obese (O) and obese with exercise (OE) groups that received a high-fat diet. All the groups received filtered water during the experimental conditions. Groups E and OE were submitted to 8 weeks of high-intensity intermittent training. Afterwards, testes were collected for sperm count, spermatogenic kinetics, histopathology, morphometry and immunodetection of androgen receptors (AR). The vas deferens was collected for sperm morphology. The results showed that obesity increased body weight, naso-anal length, liver and epididymal fat weight, abnormal spermatozoa and immunodetectable AR. Intermittent exercise decreased daily sperm production (DSP), sperm count and normal spermatozoa, whereas the number of tubules with immunodetectable AR increased. The combination of obesity and intermittent training led to reduced sperm count and DSP, although abnormal spermatozoa and the number of tubules with immunodetectable AR increased. Thus, in conclusion, both obesity and resistance training impaired testicular function during puberty in rats; and this type of exercise has also been shown to be detrimental to testicular physiology.

Cardiovascular and metabolic consequences of the association between chronic stress and high-fat diet in rats

Obesity and chronic stress are considered independent risk factors for the development of cardiovascular diseases and changes in autonomic system activity. However, the cardiovascular consequences induced by the association between high-fat diet (HFD) and chronic stress are not fully understood. We hypothesized that the association between HFD and exposure to a chronic variable stress (CVS) protocol for four weeks might exacerbate the cardiovascular and metabolic disturbances in rats when compared to these factors singly. To test this hypothesis, male Wistar rats were divided into four groups: control-standard chow diet (SD; n = 8); control-HFD (n = 8); CVS-SD (n = 8); and CVS-HFD (n = 8). The CVS consisted of repeated exposure of the rats to different inescapable and unpredictable stressors (restraint tress; damp sawdust, cold, swim stress and light cycle inversion). We evaluated cardiovascular function, autonomic activity, dietary intake, adiposity and metabolism. The HFD increased body weight, adiposity and blood glucose concentration (∼15%) in both control and CVS rats. The CVS-HFD rats showed decreased insulin sensitivity (25%) compared to CVS-SD rats. The control-HFD and CVS-HFD rats presented increased intrinsic heart rate (HR) values (∼8%). CVS increased cardiac sympathetic activity (∼65%) in both SD- and HFD-fed rats. The HFD increased basal HR (∼10%). Blood pressure and baroreflex analyzes showed no differences among the experimental groups. In conclusion, the present data indicate absence of interaction on autonomic imbalance evoked by either CVS or HFD. Additionally, HFD increased HR and evoked metabolic disruptions which are independent of stress exposure.

Physical training improves visceral adipose tissue health by remodelling extracellular matrix in rats with estrogen absence: a gene expression analysis

Adipose tissue development is associated with modifications involving extracellular matrix remodelling, and metalloproteinases play a significant role in this process. Reduced circulating sexual hormones cause impacts on the size, morphology and functions of the adipose tissue, increasing susceptibility to diseases. This study investigated whether exercise training may be an alternative strategy to combat the effects promoted by estrogen decay through modulation in gene expression patterns in the extracellular matrix (ECM) of visceral adipose tissue of ovariectomized rats. Nulliparous rats (n = 40) were randomly distributed into four groups (n = 10/group): sham sedentary (Sh-S), sham resistance training (Sh-Rt), ovariectomized sedentary (Ovx-S) and ovariectomized resistance training (Ovx-Rt). The Sh-S animals did not have any type of training. The body mass and food intake, ECM gene expression, gelatinase MMP-2 activity and adipocyte area were measured. A lack of estrogen promoted an increase in body mass, food intake and the visceral, parametrial and subcutaneous adipocyte areas. The ovariectomy upregulated the expression of MMP-2, MMP-9, TGF-β, CTGF, VEGF-A and MMP-2 activity. On the other hand, resistance training decreased the body mass, food intake and the adipocyte area of the three fat depots analysed; upregulated TIMP-1, VEGF-A and MMP-2 gene expression; downregulated MMP-9, TGF-β and CTGF gene expression; and decreased the MMP-2 activity. We speculate that resistance training on a vertical ladder could play an important role in maintaining and remodelling ECM by modulation in the ECM gene expression and MMP-2 activity, avoiding its destabilization which is impaired by the lack of estrogen.

Effects of resistance training and estrogen replacement on adipose tissue inflammation in ovariectomized rats

Estrogen deficiency is directly related to central obesity and low-grade inflammation. Hormonal replacement and exercise training are both able to decrease fat accumulation and inflammation in postmenopausal women. However, the efficiency of resistance training (RT) and estrogen replacement (ER) in minimizing adiposity and inflammation in the visceral adipose tissue (VAT) of ovariectomized (OVX) rats has not yet been elucidated. In this study, Sprague–Dawley rats were divided into the following 6 groups: sham-operated sedentary (Sham-Sed), OVX-Sed, Sham-RT, OVX-RT, OVX-Sed-ER, and OVX-RT-ER groups. ER was performed by implanting silastic capsules containing 17β-estradiol. For RT, the animals were required to climb a 1.1-m vertical ladder with conical flasks containing weights attached to their tails for 12 weeks. Histological analyses were used to evaluate morphological changes. Gene expression levels were determined by quantitative real-time reverse transcriptase polymerase chain reaction, and protein concentrations were determined using Multiplex/Luminex assays. Ovariectomy increased the body mass (BM), adipocyte area, and inflammation in the VAT, the latter of which was indicated by reduced interleukin-10 (48%) and increased tumor necrosis factor (TNF)-α concentration (∼3%). RT efficiently decreased BM, adipocyte area, and inflammation in the OVX groups. The combination of RT and ER decreased BM (19%) and the TNF-α concentration (18%) and increased the gene and protein expression levels of adiponectin (173% and 18%). These results indicate that RT and the combination of RT and ER are efficient strategies for reducing the BM and improving the inflammatory status of OVX rats.

Impact of physical exercise on visceral adipose tissue fatty acid profile and inflammation in response to a high-fat diet regimen

PURPOSE

Studies associate specific fatty-acids (FA) with the pathophysiology of inflammation. We aimed to analyze the impact of exercise on adipose tissue FA profile in response to a high-fat diet (HFD) and to ascertain whether these exercise-induced changes in specific FA have repercussions on obesity-related inflammation.

METHODS

Sprague-Dawley rats were assigned into sedentary, voluntary physical-activity (VPA) and endurance training (ET) groups fed a standard (S, 35kcal% fat) or high-fat (71kcal% fat) diets. VPA-animals had unrestricted access to wheel-running. After 9-wks, ET-animals engaged a running protocol for 8-wks, while maintained dietary treatments. The FA content in epididymal white-adipose tissue (eWAT) triglycerides was analyzed by gas-chromatography and the expression of inflammatory markers was determined using RT-qPCR, Western and slot blotting.

RESULTS

Eight-wks of ET reversed obesity-related anatomical features. HFD increased plasma tumor necrosis factor (TNF)-α content and eWAT monocyte chemoattractant protein (MCP)-1 protein expression. HFD decreased eWAT content of saturated FA and monounsaturated FA, while increased linoleic acid and prostaglandin E2 (PGE2) levels in eWAT. VPA decreased visceral adiposity, adipocyte size and MCP-1 in HFD-fed animals. The VPA and ET interventions diminished palmitoleic acid and increased linoleic acid in HFD-fed groups. Moreover, both interventions increased PGE2 levels in standard diet-fed groups and decreased in HFD. ET increased eWAT fatty acid desaturase 1 (FADS1) and elongase 5 (ELOVL5) protein content in both diet types. ET reduced eWAT inflammatory markers (TNF-α, IL-6), macrophage recruitment (MCP-1 and F4/80) and increased IL-10/TNF-α ratio in plasma and in eWAT in both diet types.

CONCLUSIONS

Exercise induced FA-specific changes independently of dietary FA composition, but only ET attenuated the inflammatory response in VAT of HFD-fed rats. Moreover, the exercise-induced FA changes did not correlate with the inflammatory response in VAT of rats submitted to HFD.

Exercise effects on perivascular adipose tissue: endocrine and paracrine determinants of vascular function

Obesity is a global epidemic, accompanied by increased risk of type 2 diabetes and cardiovascular disease. Adipose tissue hypertrophy is associated with adipose tissue inflammation, which alters the secretion of adipose tissue-derived bioactive products, known as adipokines. Adipokines determine vessel wall properties such as smooth muscle tone and vessel wall inflammation. Exercise is a mainstay of prevention of chronic, non-communicable diseases, type 2 diabetes and cardiovascular disease in particular. Aside from reducing adipose tissue mass, exercise has been shown to reduce inflammatory activity in this tissue. Mechanistically, contracting muscles release bioactive molecules known as myokines, which alter the metabolic phenotype of adipose tissue. In adipose tissue, myokines induce browning, enhance fatty acid oxidation and improve insulin sensitivity. In the past years, the perivascular adipose tissue (PVAT) which surrounds the vasculature, has been shown to control vascular tone and inflammation through local release of adipokines. In obesity, an increase in mass and inflammation of PVAT culminate in dysregulation of adipokine secretion, which contributes to vascular dysfunction. This review describes our current understanding of the mechanisms by which active muscles interact with adipose tissue and improve vascular function. Aside from the exercise-dependent regulation of canonical adipose tissue function, we will focus on the interactions between skeletal muscle and PVAT and the role of novel myokines, such as IL-15, FGF21 and irisin, in these interactions.

LINKED ARTICLES

This article is part of a themed section on Molecular Mechanisms Regulating Perivascular Adipose Tissue - Potential Pharmacological Targets? To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.20/issuetoc.

Estrogen deficiency in ovariectomized rats: can resistance training re-establish angiogenesis in visceral adipose tissue?

OBJECTIVE

The purpose of this study was to investigate the effects of resistance training on angiogenesis markers of visceral adipose tissue in ovariectomized rats.

METHOD

Adult Sprague-Dawley female rats were divided into four groups (n=6 per group): sham-sedentary, ovariectomized sedentary, sham-resistance training and ovariectomized resistance training. The rats were allowed to climb a 1.1-m vertical ladder with weights attached to their tails and the weights were progressively increased. Sessions were performed three times per week for 10 weeks. Visceral adipose tissue angiogenesis and morphology were analyzed by histology. VEGF-A mRNA and protein levels were analyzed by real-time PCR and ELISA, respectively.

RESULTS

Ovariectomy resulted in higher body mass (p=0.0003), adipocyte hypertrophy (p=0.0003), decreased VEGF-A mRNA (p=0.0004) and protein levels (p=0.0009), and decreased micro-vascular density (p=0.0181) in the visceral adipose tissue of the rats. Resistance training for 10 weeks was not able to attenuate the reduced angiogenesis in the visceral adipose tissue of the ovariectomized rats.

CONCLUSION

Our findings indicate that the resistance training program used in this study could not ameliorate low angiogenesis in the visceral adipose tissue of ovariectomized rats.

Interval aerobic training combined with strength-endurance exercise improves metabolic markers beyond caloric restriction in Zucker rats

AIMS

To investigate the effects of interval aerobic training combined with strength-endurance exercise (IASE) and caloric restriction (CR) on body composition, glycaemic and lipid profile and inflammatory markers.

METHODS AND RESULTS

Thirty-two Zucker diabetic fatty rats were randomised into 4 groups (sedentary + CR; sedentary + adlibitum; IASE + CR; and IASE + adlibitum). Training groups conducted an IASE programme in the same session, 5 days/week for 2 months. Body weight, fat and muscle mass and body water were measured using a body composition analyser. Plasma total, LDL and HDL cholesterol, phospholipids, triglycerides, insulin, adiponectin, tumour necrosis factor alpha, interleukin 1 and 10 were measured. Blood fasting and postprandial glucose were assessed. Body weight was lower in the CR compared to the adlibitum groups (p < 0.001). Fat mass was lower in the CR compared to the adlibitum (p < 0.05) and in the IASE compared to the sedentary groups (p < 0.001), but IASE increased lean mass (p < 0.001). Triglycerides were lower in the CR compared to the adlibitum groups (p < 0.001) whereas total and LDL-cholesterol and fasting glucose were reduced only in the IASE groups (all, p < 0.001). Phospholipids decreased in the CR compared to the adlibitum (p < 0.05) and the IASE compared to the sedentary groups (p < 0.001). The area under the curve after oral glucose tolerance test, insulin and homoeostatic model assessment were lower in the IASE and the CR compared to the sedentary and adlibitum groups, respectively (all, p < 0.001). Adiponectin was lower in the CR groups (p < 0.001).

CONCLUSION

Overall, IASE as well as CR were both useful interventions, especially when combined. However, IASE showed greater improvements on body composition, inflammatory and glycaemic profile than CR did.

Effect of High Intensity Interval and Continuous Swimming Training on Body Mass Adiposity Level and Serum Parameters in High-Fat Diet Fed Rats

This study aimed to investigate the effects of interval and continuous training on the body mass gain and adiposity levels of rats fed a high-fat diet. Forty-eight male Sprague-Dawley rats were randomly divided into two groups, standard diet and high-fat diet, and received their respective diets for a period of four weeks without exercise stimuli. After this period, the animals were randomly divided into six groups (n = 8): control standard diet (CS), control high-fat diet (CH), continuous training standard diet (CTS), continuous training high-fat diet (CTH), interval training standard diet (ITS), and interval training high-fat diet (ITH). The interval and continuous training consisted of a swimming exercise performed over eight weeks. CH rats had greater body mass gain, sum of adipose tissues mass, and lower serum high density lipoprotein values than CS. The trained groups showed lower values of feed intake, caloric intake, body mass gain, and adiposity levels compared with the CH group. No significant differences were observed between the trained groups (CTS versus ITS and CTH versus ITH) on body mass gains and adiposity levels. In conclusion, both training methodologies were shown to be effective in controlling body mass gain and adiposity levels in high-fat diet fed rats.

Resistance training prevents the cardiovascular changes caused by high-fat diet

AIMS

Aerobic exercise is indicated for prevention and treatment of obesity-induced cardiovascular disorders. Although the resistance training (RT) may also produce effects similar to aerobic exercise, this is not completely clear yet. In the present study, we tested if RT in moderate intensity might prevent alterations in blood pressure (BP), sympathetic modulation of systolic blood pressure (SBP), baroreflex function and the changes in renin-angiotensin system (RAS) and cytokines mRNA expression within the nucleus of the tract solitary (NTS) in rats fed with high-fat diet (HFD).

MAIN METHODS

Male Holtzman rats (300-320 g) were divided into 4 groups: sedentary with standard chow diet (SED-SD); sedentary with high-fat diet (SED-HFD); RT with standard chow diet (RT-SD); and RT with high-fat diet (RT-HFD). The trained groups performed a total of 10 weeks of moderate intensity RT in a vertical ladder. In the first 3 weeks all experimental groups were fed with SD. In the next 7 weeks, the SED-HFD and RT-HFD groups were fed with HFD.

KEY FINDINGS

In SED-HFD, BP and sympathetic modulation of SBP increased, whereas baroreflex bradycardic responses were attenuated. RT prevented the cardiovascular and inflammatory responses (increases in tumoral necrosis factor-α and interleukin-1β) produced by HFD in SED rats. The anti-inflammatory interleukin-10, angiotensin type 2 receptor, Mas receptor and angiotensin converting enzyme 2 mRNA expressions in the NTS increased in the RT-HFD compared to SED-HFD.

SIGNIFICANCE

The data demonstrated that moderate intensity RT prevented obesity-induced cardiovascular disorders simultaneously with reduced inflammatory responses and modifications of RAS in the NTS.

Short term resistance training enhanced plasma apoA-I and FABP4 levels in Streptozotocin-induced diabetic rats

BACKGROUND

Type 1 diabetes mellitus is associated with a high risk for early atherosclerotic complications. Altered lipids and lipoprotein metabolism in chronic diabetes mellitus is associated with pathogenesis of atherosclerosis and other cardiovascular diseases. The aim of this study was to investigate the effects of 4 weeks resistance training on plasma lipid profile, fatty acid binding protein (FABP) 4 and apolipoprotein (apo) A-I levels in type 1 diabetic rats.

METHODS

Thirty two male Wister rats (12-14 weeks old) were randomly divided into four groups: non-diabetic control; non-diabetic trained; diabetic control; diabetic trained. The rats in training groups were subjected to a resistance training program (3 days/wk, for 4 wk) consisted of climbing a ladder carrying a load suspended from the tail.

RESULTS

Diabetic inducing increased plasma apoA-I and decreased FABP4 levels compared with non-diabetic control group (respectively, P = 0.001 & P = 0.041). After 4 weeks' resistance training, plasma levels of apoA-I and FABP4 in the diabetic trained rats were significantly higher compared with the diabetic control group (respectively, P = 0.003 & P = 0.017). Plasma HDL-C level in diabetic trained group was higher than diabetic control group (P = 0.048). Liver triglycerides concentrations were significantly lower in both trained (non-diabetic and diabetic) groups compared with their control groups (respectively, P = 0.041 and P = 0.002).

CONCLUSION

These data indicated that resistance training may be an efficient intervention strategy to increase plasma apoA-I, HDL-C and FABP4 concentrations, along with decreases liver triglycerides in streptozotocin induced diabetic rats. Further research is needed to elucidate physiological significance of circulating FABP4 levels.

Resistance training improves body composition and increases matrix metalloproteinase 2 activity in biceps and gastrocnemius muscles of diet-induced obese rats

OBJECTIVE

We investigated the influence of resistance training on body composition and matrix metalloproteinase 2 activity in skeletal muscles of rats fed a high-fat diet.

METHODS

Thirty-two Wistar rats were divided into four experimental groups (n = 8/each) according to diet and exercise status: Control (standard diet), Obese Control (high-fat diet), Resistance Training (standard diet) and Obese Resistance Training (high-fat diet) groups. Animals were fed a high-fat diet for 12 weeks to promote excessive weight gain. Resistance Training groups performed 12 weeks of training periods after this period in a vertical ladder three times/week. Fat percentage, fat-free mass and fat mass were assessed using dual-energy X-ray absorptiometry, and matrix metalloproteinase 2 activity in biceps and gastrocnemius muscles was analyzed using zymography.

RESULTS

Resistance training significantly reduced body and fat masses and fat percentages in both trained groups (p<0.05). The maximal carrying load between trained groups was not different, but relative force was higher in the Resistance Training group (p<0.05). Of note, increased matrix metalloproteinase 2 activity was noted in the tested muscles of both trained groups (p<0.05).

CONCLUSION

In conclusion, altered body composition and muscle matrix metalloproteinase 2 activity promoted by excessive weight gain were positively modified by resistance training.

Sudden decrease in physical activity evokes adipocyte hyperplasia in 70- to 77-day-old rats but not 49- to 56-day-old rats

The cessation of physical activity in rodents and humans initiates obesogenic mechanisms. The overall purpose of the current study was to determine how the cessation of daily physical activity in rats at 49-56 days of age and at 70-77 days of age via wheel lock (WL) affects adipose tissue characteristics. Male Wistar rats began voluntary running at 28 days old and were either killed at 49-56 days old or at 70-77 days old. Two cohorts of rats always had wheel access (RUN), a second two cohorts of rats had wheel access restricted during the last 7 days (7d-WL), and a third two cohorts of rats did not have access to a voluntary running wheel after the first 6 days of (SED). We observed more robust changes with WL in the 70- to 77-day-old rats. Compared with RUN rats, 7d-WL rats exhibited greater rates of gain in fat mass and percent body fat, increased adipocyte number, higher percentage of small adipocytes, and greater cyclin A1 mRNA in epididymal and perirenal adipose tissue. In contrast, 49- to 56-day-old rats had no change in most of the same characteristics. There was no increase in inflammatory mRNA expression in either cohort with WL. These findings suggest that adipose tissue in 70- to 77-day-old rats is more protected from WL than 49- to 56-day-old rats and responds by expansion via hyperplasia.

Resistance training may concomitantly benefit body composition, blood pressure and muscle MMP-2 activity on the left ventricle of high-fat fed diet rats

OBJECTIVE

The purpose of this study was to evaluate the effect of resistance training (RT) on body composition, systolic and diastolic blood pressures (BP), and activity of muscle MMP-2 in the left ventricle of high-fat fed rats.

MATERIALS/METHODS

We have evaluated 32 male Wistar rats divided into four experimental groups (n=8/each) according to diet and exercise status: sedentary (SED; standard diet), sedentary obese (SED-OB; diet: 30% of fat), RT (RT; standard diet) and RT obese (RT-OB; diet: 30% of fat). After weaning (day 21), animals were subjected to the experimental diet according to their groups during 24 weeks. A 12-week strength-training period was used, during which the rats climbed a 1.1-m vertical ladder with weights attached to their tails. Sessions were performed three times/week (Mondays, Wednesdays and Fridays), with 4-9 climbs/session and 8-12 dynamic movements/climb.

RESULTS

RT induced higher muscle MMP-2 activity in the left ventricle in RT and RT-OB groups. Moreover, this study demonstrated that RT promoted lower body and fat masses, fat percentage, systolic and diastolic BPs and higher fat free mass in both trained groups.

CONCLUSION

RT increased muscle MMP-2 activity in the left ventricle, induced positive changes on body composition and lowered BPs in high-fat diet fed rats, suggesting that it may be a useful tool to prevent alterations induced by high-fat diet consumption.

A prescribed Chinese herbal medicine improves glucose profile and ameliorates oxidative stress in Goto-Kakisaki rats fed with high fat diet

Oxidative stress (OS) plays a role in hyperglycemia induced islet β cell dysfunction, however, studies on classic anti-oxidants didn’t show positive results in treating diabetes. We previously demonstrated that the prescribed Chinese herbal medicine preparation “Qing Huo Yi Hao” (QHYH) improved endothelial function in type 2 diabetic patients. QHYH protected endothelial cells from high glucose-induced damages by scavenging superoxide anion and reducing production of reactive oxygen species. Its active component protected C2C12 myotubes against palmitate-induced oxidative damage and mitochondrial dysfunction. In the present study, we investigated whether QHYH protected islet β cell function exacerbated by high fat diet (HFD) in hyperglycemic GK rats. 4-week-old male rats were randomly divided into high HFD feeding group (n = 20) and chow diet feeding group (n = 10). Each gram of HFD contained 4.8 kcal of energy, 52% of which from fat. Rats on HFD were further divided into 2 groups given either QHYH (3 ml/Kg/d) or saline through gastric tube. After intervention, serum glucose concentrations were monitored; IPGTTs were performed without anesthesia on 5 fasting rats randomly chosen from each group on week 4 and 16. Serum malondialdehyde (MDA) concentrations and activities of serum antioxidant enzymes were measured on week 4 and 16. Islet β cell mass and OS marker staining was done by immunohistochemistry on week 16. QHYH prevented the exacerbation of hyperglycemia in HFD feeding GK rats for 12 weeks. On week 16, it improved the exacerbated glucose tolerance and prevented the further loss of islet β cell mass induced by HFD. QHYH markedly decreased serum MDA concentration, increased serum catalase (CAT) and SOD activities on week 4. However, no differences of serum glucose concentration or OS were observed on week 16. We concluded that QHYH decreased hyperglycemia exacerbated by HFD in GK rats by improving β cell function partly via its antioxidant effect.