Beneficial effects of previous exercise training on renal changes in streptozotocin-induced diabetic female rats

Renoprotective mechanisms of exercise training against acute and chronic renal diseases - A perspective based on experimental studies

Regular exercise training can lead to several health benefits, reduce mortality risk, and increase life expectancy. On the other hand, a sedentary lifestyle is a known risk factor for chronic diseases and increased mortality. Acute kidney injury (AKI) and chronic kidney disease (CKD) represent a significant global health problem, affecting millions of people worldwide. The progression from AKI to CKD is well-recognized in the literature, and exercise training has emerged as a potential renoprotective strategy. Thus, this article aims to review the main molecular mechanisms underlying the renoprotective actions of exercise training in the context of AKI and CKD, focusing on its antioxidative, anti-inflammatory, anti-apoptotic, anti-fibrotic, and autophagy regulatory effects. For that, bibliographical research was carried out in Medline/PubMed and Scielo databases. Although the pathophysiological mechanisms involved in renal diseases are not fully understood, experimental studies demonstrate that oxidative stress, inflammation, apoptosis, and dysregulation of fibrotic and autophagic processes play central roles in the development of tissue damage. Increasing evidence has suggested that exercise can beneficially modulate these mechanisms, potentially becoming a safe and effective non-pharmacological strategy for kidney health protection and promotion. Thus, the evidence base discussed in this review suggests that an adequate training program emerges as a valuable tool for preserving renal function in experimental animals, mainly through the production of antioxidant enzymes, nitric oxide (NO), irisin, IL-10, and IL-11. Future research can continue to explore these mechanisms to develop specific guidelines for the prescription of exercise training in different populations of patients with kidney diseases.

Exercise training improves diabetic renal injury by reducing fetuin-A, oxidative stress and inflammation in type 2 diabetic rats

Background

Diabetic kidney disease (DKD) stands as a primary contributor to end-stage renal disease, associated with heightened mortality in cardiovascular diseases. This study aimed to explore the impact of an eight-week high-intensity interval training (HIIT) on renal injury in diabetic rats.

Methods

Twenty-eight male Wistar rats were randomly allocated into four groups: healthy control (CTL), diabetic control (DC), exercise (EX), and diabetes-exercise (D + EX). Induction of diabetes in the DC and D + EX groups occurred through a two-month high-fat diet followed by a single dose of 35 mg/kg streptozotocin (STZ). Rats in the EX and D + EX groups underwent 4-10 intervals of HIIT (80-100% Vmax) over 8 weeks. Subsequently, pathological and biochemical parameters were assessed in the serum and kidney tissue of the experimental groups.

Results

In the DC group, diabetes led to elevated kidney damage, glomerulosclerosis, fasting blood glucose (FBG), Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) index, animal weight, kidney dysfunction, albuminuria, and glomerular filtration rate. Additionally, serum and kidney levels of fetuin-A increased, along with kidney levels of KIM-1. Mechanistically, diabetes induction resulted in kidney inflammation by elevating levels of tumor necrosis factor-alpha (TNF-α), transforming growth factor beta (TGF-β), and interleukin 6 (IL-6), while reducing IL-10 levels and increasing the IL-6/IL-10 ratio. Furthermore, diabetes triggered renal oxidative stress, evidenced by increased Malondialdehyde (MDA) levels and decreased levels of glutathione peroxidase (GPx), catalase, and superoxide dismutase (SOD). HIIT mitigated the adverse effects of diabetes in the D + EX group compared to the DC group.

Conclusion

Our findings suggest that HIIT ameliorates type 2 diabetes (T2D)-induced kidney damage by mitigating inflammation, lowering serum levels of fetuin-A, and bolstering antioxidant defenses. This study highlights the potential of HIIT as a time-efficient intervention for diabetic nephropathy.

Exercise in Diabetic Nephropathy: Protective Effects and Molecular Mechanism

Diabetic nephropathy (DN) is a serious complication of diabetes, and its progression is influenced by factors like oxidative stress, inflammation, cell death, and fibrosis. Compared to drug treatment, exercise offers a cost-effective and low-risk approach to slowing down DN progression. Through multiple ways and mechanisms, exercise helps to control blood sugar and blood pressure and reduce serum creatinine and albuminuria, thereby alleviating kidney damage. This review explores the beneficial effects of exercise on DN improvement and highlights its potential mechanisms for ameliorating DN. In-depth understanding of the role and mechanism of exercise in improving DN would pave the way for formulating safe and effective exercise programs for the treatment and prevention of DN.

The effect of pentoxifylline and different types of exercise training on coagulation factors in a rat endometriosis model

Objectives

This study evaluated the effects of high-intensity interval training (HIIT), moderate-intensity continuous training (MICT), and pentoxifylline (PTX) on coagulation factors, including the amount and percentage of lymphocytes, PLC, PLR, aPTT, PT, PT.I.N. R in a model of rats with endometriosis.

Methods

Endometriosis was surgically induced in female Sprague-Dawley rats. The rats with confirmed endometrial implants were divided into control, MICT, pentoxifylline (D), HIIT+D, and MICT+D, HIIT groups. D and exercise interventions were performed for eight weeks. Then, the macroscopic size of endometriosis lesions was measured, and inflammatory factors (count and percentage of lymphocytes) and coagulation factors, including PLC, PLR, aPTT, PT, PT.I.N. R, and PLR in blood samples were evaluated.

Results

D significantly decreased the volume of lesions and significantly increased PT and PT.I.N. R in blood. HIIT decreased the volume of lesions and significantly increased PT. MICT did not cause significant effects on the target variables. MICT+D decreased the volume of lesions. HIIT+D significantly decreased the volume of lesions and PLC and increased aPTT as well as the count and percentage of lymphocytes, PT, and PT.I.N. R, and decreased PLR.

Conclusions

All interventions(except for MICT) especially HIIT+D and D by priority, induced a significant effect on reducing some indices of inflammation and coagulation.

Physical exercise as a friend not a foe in acute kidney diseases through immune system modulation

Regular and moderate exercise is being used for therapeutic purposes in treating several diseases, including cancer, cardiovascular diseases, arthritis, and even chronic kidney diseases (CKDs). Conversely, extenuating physical exercise has long been pointed out as one of the sources of acute kidney injury (AKI) due to its severe impact on the body's physiology. AKI development is associated with increased tubular necrosis, which initiates a cascade of inflammatory responses. The latter involves cytokine production, immune cell (macrophages, lymphocytes, and neutrophils, among others) activation, and increased oxidative stress. AKI can induce prolonged fibrosis stimulation, leading to CKD development. The need for therapeutic alternative treatments for AKI is still a relevant issue. In this context arises the question as to whether moderate, not extenuating, exercise could, on some level, prevent AKI. Several studies have shown that moderate exercise can help reduce tissue damage and increase the functional recovery of the kidneys after an acute injury. In particular, the immune system can be modulated by exercise, leading to a better recovery from different pathologies. In this review, we aimed to explore the role of exercise not as a trigger of AKI, but as a modulator of the inflammatory/immune system in the prevention or recovery from AKI in different scenarios. In AKI induced by ischemia and reperfusion, sepsis, diabetes, antibiotics, or chemotherapy, regular and/or moderate exercise could modulate the immune system toward a more regulatory immune response, presenting, in general, an anti-inflammatory profile. Exercise was shown to diminish oxidative stress, inflammatory markers (caspase-3, lactate dehydrogenase, and nitric oxide), inflammatory cytokines (interleukin (IL)-1b, IL-6, IL-8, and tumor necrosis factor-α (TNF-α)), modulate lymphocytes to an immune suppressive phenotype, and decrease tumor necrosis factor-β (TGF-β), a cytokine associated with fibrosis development. Thus, it creates an AKI recovery environment with less tissue damage, hypoxia, apoptosis, or fibrosis. In conclusion, the practice of regular moderate physical exercise has an impact on the immune system, favoring a regulatory and anti-inflammatory profile that prevents the occurrence of AKI and/or assists in the recovery from AKI. Moderate exercise should be considered for patients with AKI as a complementary therapy.

Visibility Graph Analysis of Heartbeat Time Series: Comparison of Young vs. Old, Healthy vs. Diseased, Rest vs. Exercise, and Sedentary vs. Active

Using the visibility graph algorithm (VGA), a complex network can be associated with a time series, such that the properties of the time series can be obtained by studying those of the network. Any value of the time series becomes a node of the network, and the number of other nodes that it is connected to can be quantified. The degree of connectivity of a node is positively correlated with its magnitude. The slope of the regression line is denoted by k-M, and, in this work, this parameter was calculated for the cardiac interbeat time series of different contrasting groups, namely: young vs. elderly; healthy subjects vs. patients with congestive heart failure (CHF); young subjects and adults at rest vs. exercising young subjects and adults; and, finally, sedentary young subjects and adults vs. active young subjects and adults. In addition, other network parameters, including the average degree and the average path length, of these time series networks were also analyzed. Significant differences were observed in the k-M parameter, average degree, and average path length for all analyzed groups. This methodology based on the analysis of the three mentioned parameters of complex networks has the advantage that such parameters are very easy to calculate, and it is useful to classify heartbeat time series of subjects with CHF vs. healthy subjects, and also for young vs. elderly subjects and sedentary vs. active subjects.

High intensity interval training is superior to moderate intensity continuous training in enhancing the anti-inflammatory and apoptotic effect of pentoxifylline in the rat model of endometriosis

This study investigated the effects of pentoxifylline (PTX), high intensity interval training (HIIT) and moderate intensity continuous training (MICT) separately and in combination, on inflammatory and apoptotic pathways in the rat model of induced endometriosis. Endometriosis was induced through surgery on female Sprague-Dawley rats. Six weeks after the first surgery, the second look laparotomy was performed. After induction of endometriosis in rats, they were divided into control, MICT, PTX, MICT+ PTX, HIIT, HIIT+PTX groups. Two weeks after the second look laparotomy, PTX and exercise training interventions were performed for eight weeks. Endometriosis lesions were assessed histologically. Proteins content of the NF-κB, PCNA and Bcl-2 were measured by immunoblotting and genes expression of the TNF-α and VEGF were measured by Real-time PCR methods. Findings of the study indicated that, PTX significantly decreased volume and histological grading of lesions, proteins of NF-κB and Bcl-2; and genes expression of the TNF-α, and VEGF in lesions. HIIT significantly decreased volume and histological grading of lesions, NF-κB, TNF-α and VEGF in lesions. MICT did not induce any significant effect on the study variables. Although, MICT+PTX decreased significantly volume and histological grading of lesions, as well as NF-κB, and Bcl-2 in lesions, however, these factors were not significantly different with the PTX group. HIIT+PTX decreased significantly all of the study variables compared to other interventions, except for VEGF when compared to PTX. In summary, combination of PTX and HIIT can induce enhancing effect on suppression of endometriosis through suppressing inflammation, angiogenesis, and proliferation and enhancing apoptosis.

Benefits of high-intensity interval training compared to continuous training to reduce apoptotic markers in female rats with cisplatin nephrotoxicity - possible modulatory role of IL-11

Apoptotic signaling pathways are involved in acute kidney injury (AKI) induced by the antineoplastic drug cisplatin (Cis). Mechanical stress is known to increase interleukin (IL) -11, a pleiotropic cytokine with antiapoptotic and antinecrotic effects. We compared the impact of high-intensity interval training (HIIT) with low-intensity continuous training (LICT) and moderate-intensity continuous training (MICT) on renal levels of IL-11 and the expression of apoptotic markers in female rats with nephrotoxicity induced by Cis. For that, the animals were divided into five groups (n = 7): control and sedentary (C + S); Cis and sedentary (Cis + S); Cis and LICT (Cis + LICT); Cis and MICT (Cis + MICT) and Cis and HIIT (Cis + HIIT). At the end of 8 weeks of treadmill running, the rats received a single injection of Cis (5 mg/kg), and 7 days later they were euthanized. Serum and kidney samples were collected to assess the blood urea nitrogen (BUN), gene expression of TNF receptor 1 (TNFR1) and 2 (TNFR2), caspase-3, (p38) MAPK (MAPK14), p53, Bax, Bak, Bcl-2, and Bcl-xL, renal levels of IL-11, IL-8, and p53, and immunolocalization of cleaved caspase-3, Bax, Bcl-2, and (p38) MAPK in renal tissue. Our data indicate that all trained groups showed a significant intensity-dependent increase in renal levels of IL-11 associated with reduced local expression of proapoptotic and increased antiapoptotic markers, but these effects were more pronounced with HIIT. So, HIIT appears to provide superior renoprotection than traditional continuous training by modulating apoptotic signaling pathways, and this effect can be related to the increase in renal levels of IL-11.

Impact of exercise on renal function, oxidative stress, and systemic inflammation among patients with type 2 diabetic nephropathy

Background

Diabetic nephropathy (DN) is a prevalent microvascular diabetic complication all over the world.

Objective

This study was designed to measure oxidative stress, systemic inflammation and kidney function response to exercise training in patients with type 2 diabetic (T2DM) nephropathy.

Material and Methods

Eighty obese T2DM patients (50 males and 30 females), their body mass index (BMI) mean was 33.85±3.43 Kg/m² and the mean of diabetes chronicity was 12.53±2.64 year participated in the present study and enrolled two groups; group I: received aerobic exercise training and group II: received no training intervention.

Results

The mean values of creatinine, interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α) and malondialdehyde (MDA) were significantly decreased, while the mean values of interleukin-10 (IL-10), glutathione peroxidase (GPx) and glutathione (GSH) were significantly increased in group (A) after the aerobic exercise training, however the results of the control group were not significant. In addition, there were significant differences between both groups at the end of the study (P<0.05).

Conclusion

There is evidence that aerobic exercise training modulated oxidative stress and inflammatory cytokines and improved renal function among patients with diabetic nephropathy.

The effects of exercise on kidney injury: the role of SIRT1

In patients with kidney injury, muscle mass and strength decrease with altered muscle protein synthesis and degradation along with complications such as inflammation and low physical activity. A treatment strategy to maintain muscle metabolism in kidney injury is important. One of the proposed strategies in this regard is exercise, which in addition to inducing muscle hypertrophy, reducing plasma creatinine and urea and decreasing the severity of tubal injuries, can boost immune function and has anti-inflammatory effects. One of the molecules that have been considered as a target in the treatment of many diseases is silent information regulator 1 (SIRT1). Exercise increases the expression of SIRT1 and improves its activity. Therefore, studies that examined the effect of exercise on kidney injury considering the role of SIRT1 in this effect were reviewed to determine the direction of kidney injury research in future regarding to its prevalence, especially following diabetes, and lack of definitive treatment. In this review, we found that SIRT1 can be one of renoprotective target pathways of exercise. However, further studies are needed to determine the role of SIRT1 in different kidney injuries following exercise according to the type and severity of exercise, and the type of kidney injury.

Swimming training modulates lung injury induced by ovariectomy in diabetic rats: involvement of inflammatory and fibrotic biomarkers

CONTEXT

Previous studies have noted that the incidence of inflammatory and fibrotic diseases is higher in diabetic menopausal women.

OBJECTIVE

In the present study, we evaluated effects of swimming training on inflammatory and fibrotic biomarkers in the lung of ovariectomized diabetic rats.

MATERIALS AND METHODS

Forty female rats were assigned into four groups: sham; rats underwent surgery without ovariectomies, OVX: rats that underwent ovariectomies, OVX.Dia: ovariectomized rats with high-fat diet, OVX.Dia. Exe: ovariectomized diabetic rats with 8 weeks of swimming training. At the end of experiment, protein expressions were assessed with western blot. Lung sections were subjected to immunohistochemical and haematoxylin eosin staining.

RESULTS

There was a significant difference in the protein expressions between exercise and ovariectomized diabetic groups (p < .05).

CONCLUSION

The present study showed strong potential of swimming training on oestrogen deficient diabetic lung. These data encourage further investigation into the inclusive effects of exercise in menopausal diabetic women.

The effects of two different dietary regimens during exercise on outcome of experimental acute kidney injury

BACKGROUND

Acute kidney injury (AKI) is a syndrome characterized by rapid loss of excretory function of kidney. Both exercise and some diets have been shown to increase silent information regulator (SIRT1) expression leading to reduction of kidney injury. In this study, the effect of two different diets during exercise on kidney function, oxidative stress, inflammation and also SIRT1 in AKI was investigated.

MATERIALS AND METHODS

A number of rats were randomly divided into four groups; control without exercise, control with exercise, exercise + calorie restriction (CR), and exercise + time restriction (TR). Each group was divided into two subgroups of without AKI and with AKI (six rats in each group). Endurance exercise and diets were implemented before AKI. Serum urea and creatinine, urinary albumin, kidney malondialdehyde (MDA), total antioxidant capacity (TAC), transforming growth factor (TGF-β1), and SIRT1 levels, glomerular filtration rate (GFR) and relative kidney weight were measured before and 24 h after AKI induction.

RESULTS

After induction of kidney injury, serum urea and creatinine, urinary albumin, kidney MDA and TGF-β1 levels increased in rats with both previous exercise and no previous exercise, while GFR, and kidney TAC and SIRT1 levels significantly decreased. These changes after AKI were less in the group with previous exercise than in the group that had no exercise (p <0.001). The TR diet during exercise caused a less increase in serum urea (p <0.01) and creatinine (p <0.01), and urinary albumin (p <0.001) levels after the injury compared to the just exercise group. Also, both CR and TR diets during exercise caused less change in MDA (p <0.001) and TAC (p <0.05, p <0.001, respectively) levels compared to just exercise group.

CONCLUSIONS

The results showed that exercise alone had no effect on preventing function impairment of kidney, oxidative stress, inflammation and also SIRT1 alteration following AKI, although these indexes were less among those with exercise than those without exercise. However, when the CR and TR diets were implemented during exercise, strong renoprotective effects appeared, and the protective effect of TR diet was greater.

High-intensity interval training is more effective than continuous training to reduce inflammation markers in female rats with cisplatin nephrotoxicity

AIMS

Cisplatin (CP) is an antineoplastic widely used in the treatment of various solid tumors, however, its clinical application is limited by nephrotoxicity. Here, we compared the impact of preconditioning with high-intensity interval training (HIIT) with continuous training of low (LIT) and moderate (MIT) intensity on innate immunity markers in female rats with CP-induced acute kidney injury.

MATERIALS AND METHODS

The rats were divided into five groups (n = 7): saline control and sedentary (C + S); CP and sedentary (CP + S); CP and LIT (CP + LIT); CP and MIT (CP + MIT) and CP and HIIT (CP + HIIT). The training intensity was determined by a maximum running test. At the end of training, the rats received a single dose of CP (5 mg/kg), and 7 days later they were euthanized. We evaluated renal function parameters (serum creatinine, glomerular filtration rate and proteinuria), renal structure, macrophage tissue infiltration, immunolocalization of nuclear transcription factor kappa B (NF-κB), renal levels of tumor necrosis factor-alpha (TNF-α), interleukin 1β (IL-1β), and interleukin 6 (IL-6), and gene expression of monocyte chemoattractant protein-1 (MCP-1), toll-like receptor 4 (TLR4), and NF-κB in renal tissue.

KEY FINDINGS

Although both MIT and HIIT attenuated the degree of renal injury, only the HIIT prevented changes in renal function. The three training protocols mitigated the increase in expression of all inflammatory markers, however, this effect was more pronounced in HIIT.

SIGNIFICANCE

All training protocols promoted renoprotective actions, but HIIT was more effective in mitigating CP-induced acute kidney injury, in part by modulation of important markers of the innate immune response.

Ovarian hormones influence immune response to Staphylococcus aureus infection

Objective

Staphylococcus aureus infections remain associated with considerable morbidity and mortality in both hospitals and the community. There is little information regarding the role of ovarian hormones in infections caused by S. aureus. The aim of this study was to evaluate the effects of ovariectomy in the immune response induced by S. aureus.

Methods

Female mice BALB/c were ovariectomized (OVX) to significantly reduce the level of ovarian hormones. We also used sham-operated animals. The mice were inoculated intraperitoneally with S. aureus. Blood samples were collected for leukocyte count and bacterial quantification. The uterus and spleen were removed and weighed to calculate the uterine and splenic indexes. Lungs were removed and fractionated for immunohistochemical analysis for macrophage detection (anti-CD68) and relative gene expression of IL-6, IL-1β and TNF-α by RT-PCR.

Results

Ovariectomy enlarged spleen size and generally increased circulating lymphocytes. OVX females experienced a continuation of the initial reduction of lymphocytes and a monocyte and neutrophil late response compared to shams (p ≥ 0.05). Moreover, OVX females showed neutropenia after 168 h of infection (p ≥ 0.05). Macrophage response in the lungs were less pronounced in OVX females in the initial hours of infection (p ≥ 0.01). OVX females showed a higher relative gene expression of IL-1β, IL-6 and TNF-α in the lung at the beginning of the infection compared to sham females (p ≥ 0.01). Among the uninfected females, the OVX control females showed a higher expression of IL-6 in the lung compared to the sham control females (p ≥ 0.05). In this model, the lack of ovarian hormones caused a minor increase in circulating leukocytes during the initial stage of infection by S. aureus and increased pulmonary gene expression of IL-1β, IL-6, and TNF-α. Ovariectomy alone enlarged the spleen and increased circulating lymphocytes. Ovarian hormones acted as immunoprotectors against S. aureus infection.

Entropy Analysis of RR-Time Series From Stress Tests

The RR-interval time series or tachograms obtained from electrocardiograms have been widely studied since they reflect the cardiac variability, and this is an indicative of the health status of a person. The tachogram can be seen as a highly non-linear and complex time series, and therefore, should be analyzed with non-linear techniques. In this work, several entropy measures, Sample Entropy (SampEn), Approximate Entropy (ApEn), and Fuzzy Entropy (FuzzyEn) are used as a measure of heart rate variability (HRV). Tachograms belonging to thirty-nine subjects were obtained from a cardiac stress test consisting of a rest period followed by a period of moderate physical activity. Subjects are grouped according to their physical activity using the IPAQ sedentary and active questionnaire, we work with youth and middle-aged adults. The entropy measures for each group show that for the sedentary subjects the values are high at rest and decrease appreciably with moderate physical activity, This happens for both young and middle-aged adults. These results are highly reproducible. In the case of the subjects that exercise regularly, an increase in entropy is observed or they tend to retain the entropy value that they had at rest. It seems that there is a possible correlation between the physical condition of a person with the increase or decrease in entropy during moderate physical activity with respect to the entropy at rest. It was also observed that entropy during longer physical activity tests tends to decrease as fatigue accumulates, but this decrease is small compared to the change that occurs when going from rest to physical activity.

Influence of exercise training on diabetic kidney disease: A brief physiological approach

IMPACT STATEMENT

Diabetic kidney disease (DKD) is associated with increased mortality in diabetic patients and has a negative impact on public health. The identification of potential therapies that help the management of DKD can contribute to the improvement of health and quality of life of patients. Thus, this paper is timely and relevant because, in addition to presenting a concise review of the pathogenesis and major pathophysiological mechanisms of DKD, it addresses the most recent findings on the impact of exercise training on this disease. Thus, since non-pharmacological interventions have gained increasing attention in the fight against chronic diseases, this paper appears as an important tool to increase knowledge and stimulate innovative research on the impact of exercise on kidney disease.

Long-term moderate intensity exercise alleviates myocardial fibrosis in type 2 diabetic rats via inhibitions of oxidative stress and TGF-β1/Smad pathway

Exercise has an effect on the reduction of myocardial fibrosis in diabetic rats as previously reported, in which oxidative stress and the TGF-β1/Smad signaling pathway may play key roles. There is little direct experimental evidence that exercise alleviates myocardial fibrosis in type 2 diabetes mellitus (T2DM). Here we established a type 2 diabetic model by using streptozotocin and a high-fat diet. Rats were divided into groups of normal control (NC), T2DM and T2DM plus exercise (T2DME). The T2DME group received further treadmill training at moderate intensity for 8 weeks. Histological and biochemical methods were used to detect the benefits of exercise to T2DM. Results showed that the weight of rats in the T2DM group dropped dramatically, along with significant increases in blood glucose, myocardial fibrosis and oxidative stress, associated with upregulated expression of factors of myocardial fibrosis, except Smad7. Exercise largely reversed T2DM-induced alterations in factors of myocardial fibrosis, including suppressing expression of MMP-2, CTGF, TGF-β1, p-Smad2 and p-Smad3, and increased expression of TIMP-1 and Smad7. Therefore, exercise might be considered an alternative therapeutic remedy for diabetic cardiomyopathy.

Preventive effect of exercise training on diabetic kidney disease in ovariectomized rats with type 1 diabetes

IMPACT STATEMENT

To date, no studies have been found evaluating the effects of physical exercise on renal function and structure changes in ovariectomized rats with type 1 diabetes. Therefore, this work emerges with an important tool for strengthening and expanding innovative research on exercise with potential for the prevention of renal diseases in ovariectomized diabetic rats, and future development of studies that seek to increase scientific knowledge about the beneficial effects of physical exercise on renal diseases in humans.

Aerobic exercise can modulate the underlying mechanisms involved in the development of diabetic complications

Diabetes mellitus is a highly prevalent metabolic disorder that affects many molecular pathways, causing a shift from a physiologic to a pathophysiologic state. Alterations in the molecular pathways promote diabetic complications and, thus, many medical and nonmedical therapies have been directed at preventing these complications. Despite the beneficial effects on moderating glycemic control, medical therapies may also have unfavorable side effects. This makes nonmedical therapeutic approaches more attractive due to lower pharmacological side effects of these strategies compared to medical agents. Aerobic exercise is now considered as a major nonmedical strategy that can promote beneficial and protective effects to counteract the development of diabetic complications via attenuation of the major molecular mechanisms involved in diabetes.

Aerobic interval exercise improves renal functionality and affects mineral metabolism in obese Zucker rats

Obesity, metabolic syndrome, and renal injury are considered risk factors for type 2 diabetes, as well as kidney disease. Functional and structural changes in the kidney as consequence of obesity and metabolic syndrome may lead to impaired mineral metabolism in what is known as chronic kidney disease-mineral and bone disorder. Lifestyle interventions such as physical activity are good strategies to manage these pathologies and therefore, prevent the loss of kidney functionality and related complications in mineral metabolism. In this study, we have used 40 male Zucker rats that were randomly allocated into four different experimental groups, two of them (an obese and a lean one) performed an aerobic interval training protocol, and the other two groups were sedentary. At the end of the experimental period (8 wk), urine, plasma, and femur were collected for biochemical and mineral composition analysis, whereas the kidney was processed for histological studies. The obese rats exhibited albuminuria, glomerulosclerosis, and hypertrophy in glomeruli and renal tubule in some areas, together with alterations in mineral content of plasma but not of femur. The training protocol prevented the generation of albuminuria and glomerulosclerosis, showing a significant action on plasma and bone mineral levels. Therefore, the specific training protocol used in this study was able to prevent the development of diabetic nephropathy and affected the metabolism of certain minerals.

Aerobic Exercise Training Alleviates Renal Injury by Interfering with Mitochondrial Function in Type-1 Diabetic Mice

BACKGROUND Diabetic nephropathy was one of the most serious and harmful diabetic complications, characterized by progressive loss of renal function and renal fibrosis. Aerobic exercise training is an important non-pharmacologic method to prevent and treat diabetes mellitus and diabetic complications. MATERIAL AND METHODS Intraperitoneal (i.p.) injection of streptozocin (STZ) was used to construct a type 1 diabetic mouse model. Renal function and mitochondrial function were measured by urinary protein level, Masson staining and ATP, superoxide production, and membrane potential, respectively. The purpose of the research was to explore the effect of aerobic exercise training on renal and renal mitochondrial function, as well as the expression of Sirt1and PGC1α in type-1 diabetic mice. RESULTS Sedentary diabetic mice exhibited increased urinary protein level, blood glucose, and collagen deposition in renal tissues compared with sedentary control mice, which were significantly mitigated by aerobic exercise training. Diabetic mice displayed renal tissue mitochondrial dysfunction (decreased mitochondrial ATP production and membrane potential), as well as increased mitochondrial superoxide production, which were reversed by aerobic exercise. By using Western blot analysis, we identified the decreased expression of Sirt1 and PGC1α in the renal tissue of diabetic mice, which were partly reversed by aerobic exercise training. Data showed that silencing of Sirt1 abrogated the beneficial effect of aerobic exercise training against diabetes-induced mitochondrial abnormalities and renal damage in mice. CONCLUSIONS Aerobic exercise training alleviates diabetes-induced renal injury by improving mitochondrial function.

Changes in the Complexity of Heart Rate Variability with Exercise Training Measured by Multiscale Entropy-Based Measurements

Quantifying complexity from heart rate variability (HRV) series is a challenging task, and multiscale entropy (MSE), along with its variants, has been demonstrated to be one of the most robust approaches to achieve this goal. Although physical training is known to be beneficial, there is little information about the long-term complexity changes induced by the physical conditioning. The present study aimed to quantify the changes in physiological complexity elicited by physical training through multiscale entropy-based complexity measurements. Rats were subject to a protocol of medium intensity training ( n = 13 ) or a sedentary protocol ( n = 12 ). One-hour HRV series were obtained from all conscious rats five days after the experimental protocol. We estimated MSE, multiscale dispersion entropy (MDE) and multiscale SDiff q from HRV series. Multiscale SDiff q is a recent approach that accounts for entropy differences between a given time series and its shuffled dynamics. From SDiff q , three attributes (q-attributes) were derived, namely SDiff q m a x , q m a x and q z e r o . MSE, MDE and multiscale q-attributes presented similar profiles, except for SDiff q m a x . q m a x showed significant differences between trained and sedentary groups on Time Scales 6 to 20. Results suggest that physical training increases the system complexity and that multiscale q-attributes provide valuable information about the physiological complexity.

Previous Exercise Training Reduces Markers of Renal Oxidative Stress and Inflammation in Streptozotocin-Induced Diabetic Female Rats

The aim of this study is to evaluate the effects of regular moderate exercise training initiated previously or after induction of diabetes mellitus on renal oxidative stress and inflammation in STZ-induced diabetic female rats. For this purpose, Wistar rats were divided into five groups: sedentary control (SC), trained control (TC), sedentary diabetic (SD), trained diabetic (TD), and previously trained diabetic (PTD). Only the PTD group was submitted to treadmill running for 4 weeks previously to DM induction with streptozotocin (40 mg/kg, i.v). After confirming diabetes, the PTD, TD, and TC groups were submitted to eight weeks of exercise training. At the end of the training protocol, we evaluated the following: glycosuria, body weight gain, plasma, renal and urinary levels of nitric oxide and thiobarbituric acid reactive substances, renal glutathione, and immunolocalization of lymphocytes, macrophages, and nuclear factor-kappa B (NF-κB/p65) in the renal cortex. The results showed that exercise training reduced glycosuria, renal TBARS levels, and the number of immune cells in the renal tissue of the TD and PTD groups. Of note, only previous exercise increased weight gain and urinary/renal NO levels and reduced NF-κB (p65) immunostaining in the renal cortex of the PTD group. In conclusion, our study shows that exercise training, especially when initiated previously to diabetes induction, promotes protective effects in diabetic kidney by reduction of renal oxidative stress and inflammation markers in female Wistar rats.