Long-term physical training increases liver IGF-I in diabetic rats

The Effect of Different Exercise Modalities on Sertoli-germ Cells Metabolic Interactions in High-fat Diet-induced Obesity Rat Models: Implication on Glucose and Lactate Transport, Igf1, and Igf1R-dependent Pathways

The study aimed to uncover a unique aspect of obesity-related metabolic disorders in the testicles induced by a high-fat diet (HFD) and explored the potential mitigating effects of exercise modalities on male fertility. Thirty mature male Wistar rats were randomly assigned to control, HFD-sole, moderate-intensity exercise with HFD (HFD+MICT), high-intensity continuous exercise with HFD (HFD+HICT), and high-intensity interval exercise with HFD (HFD+HIIT) groups (n=6/group). Intracytoplasmic carbohydrate (ICC) storage, expression levels of GLUT-1, GLUT-3, MCT-4, Igf1, and Igf1R, and testicular lactate and lactate dehydrogenase (LDH) levels were assessed. ICC storage significantly decreased in HFD-sole rats, along with decreased mRNA and protein levels of GLUT-1, GLUT-3, MCT-4, Igf1, and Igf1R. The HFD-sole group exhibited a notable reduction in testicular lactate and LDH levels (p<0.05). Conversely, exercise, particularly HIIT, upregulated ICC storage, expression levels of GLUT-1, GLUT-3, MCT-4, Igf1, and Igf1R, and enhanced testicular lactate and LDH levels. These results confirm that exercise, especially HIIT, has the potential to mitigate the adverse effects of HFD-induced obesity on testicular metabolism and male fertility. The upregulation of metabolite transporters, LDH, lactate levels, Igf1, and Igf1R expression may contribute to maintaining metabolic interactions and improving the glucose/lactate conversion process. These findings underscore the potential benefits of exercise in preventing and managing obesity-related male fertility issues.

Relationship between physical exercise and COVID-19 (SARS-CoV-2): systematic review

Background

The SARS-CoV virus is a precursor to the SARS-CoV-2 virus (COVID-19) and has caused millions of deaths worldwide. Although exercise can be a non-pharmacological means for the prevention and treatment of various diseases, the effects on COVID-19 patients are not yet completely clear.

Aims

The aim of this study was to investigate the relationship between physical exercise and symptoms caused by COVID-19.

Methods

The present systematic review was sent for evaluation and received the PROSPERO registration protocol-CRD42021257475. The search for studies related to health and physical exercise was carried out in the following databases; the "National Library in Medicine MEDLINE-Ovid", "Embase", "Web of Science", "SportDiscus-Ebsco", and "Scopus".

Results

Ten articles were included in the systematic review and the findings demonstrated the protective effects of physical exercise in patients with COVID-19. These effects were observed both in symptoms and in the period of hospitalization. In addition, the results show that the benefits of physical exercise seem to collaborate both in an individual manner and as an alternative to drug therapy. Finally, it was possible to verify the effect of physical exercise on variables, such as quality of life, cardiorespiratory capacity, and immunological biomarkers, and on the symptoms of the new Coronavirus.

Conclusions

It is possible to conclude that physical exercise can be a component for the treatment of COVID-19. In addition, it could help to reduce the symptoms and severity of COVID-19, and may be considered as an adjunct to drug therapy in patients contaminated with SARS-CoV-2.

Effects of muscular strength training and growth hormone (GH) supplementation on femoral bone tissue: analysis by Raman spectroscopy, dual-energy X-ray absorptiometry, and mechanical resistance

The aim of the present study was to verify the effects of muscular strength training and growth hormone (GH) supplementation on femoral bone tissue by Raman spectroscopy (Raman), dual-energy X-ray absorptiometry (DXA), and mechanical resistance (F-max) analysis. A total of 40 male Wistar animals, 60 days old, were used. The animals were distributed into four groups: control (C), control with GH (GHC), muscular strength training (T), and muscular strength training with GH (GHT). Blood samples were collected for the quantification of creatine kinase (CK-MB) and the femurs were removed for analysis by Raman, DXA, and F-max. A more pronounced increase in the bone mineral components was verified in the T group, for all the variables obtained by the Raman (calcium, phosphate, amide, and collagen). In addition, for animals submitted to GH supplementation, there was a reduction in the variable bone mineral density (BMD) obtained by the DXA (p < 0.05). Finally, the animals that received GH supplementation presented a higher F-max, but without statistical significance (p > 0.05). It was concluded that animals that received GH supplementation demonstrated a decrease in BMD. In addition, T alone was able to promote increased calcium, phosphate, amide, and collagen compounds in bone tissue.

Physical training reverses changes in hepatic mitochondrial diameter of Alloxan-induced diabetic rats

OBJECTIVE

To investigate the effects of physical training on metabolic and morphological parameters of diabetic rats.

METHODS

Wistar rats were randomized into four groups: sedentary control, trained control, sedentary diabetic and trained diabetic. Diabetes mellitus was induced by Alloxan (35mg/kg) administration for sedentary diabetic and Trained Diabetic Groups. The exercise protocol consisted of swimming with a load of 2.5% of body weight for 60 minutes per day (5 days per week) for the trained control and Trained Diabetic Groups, during 6 weeks. At the end of the experiment, the rats were sacrificed and blood was collected for determinations of serum glucose, insulin, albumin and total protein. Liver samples were extracted for measurements of glycogen, protein, DNA and mitochondrial diameter determination.

RESULTS

The sedentary diabetic animals presented decreased body weight, blood insulin, and hepatic glycogen, as well as increased glycemia and mitochondrial diameter. The physical training protocol in diabetic animals was efficient to recovery body weight and liver glycogen, and to decrease the hepatic mitochondrial diameter.

CONCLUSION

Physical training ameliorated hepatic metabolism and promoted important morphologic adaptations as mitochondrial diameter in liver of the diabetic rats.

Therapeutic Approaches to Nonalcoholic Fatty Liver Disease: Exercise Intervention and Related Mechanisms

Exercise training ameliorates nonalcoholic fatty liver disease (NAFLD) as well as obesity and metabolic syndrome. Although it is difficult to eliminate the effects of body weight reduction and increased energy expenditure-some pleiotropic effects of exercise training-a number of studies involving either aerobic exercise training or resistance training programs showed ameliorations in NAFLD that are independent of the improvements in obesity and insulin resistance. In vivo studies have identified effects of exercise training on the liver, which may help to explain the "direct" or "independent" effect of exercise training on NAFLD. Exercise training increases peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α) expression, improves mitochondrial function and leads to reduced hepatic steatosis, inflammation, fibrosis, and tumor genesis. Crosstalk between the liver and adipose tissue, skeletal muscle and the microbiome is also a possible mechanism for the effect of exercise training on NAFLD. Although numerous studies have reported benefits of exercise training on NAFLD, the optimal duration and intensity of exercise for the prevention or treatment of NAFLD have not been established. Maintaining adherence of patients with NAFLD to exercise training regimes is another issue to be resolved. The use of comprehensive analytical approaches to identify biomarkers such as hepatokines that specifically reflect the effect of exercise training on liver functions might help to monitor the effect of exercise on NAFLD, and thereby improve adherence of these patients to exercise training. Exercise training is a robust approach for alleviating the pathogenesis of NAFLD, although further clinical and experimental studies are required.

The glucoregulatory response to high-intensity aerobic exercise following training in rats with insulin-treated type 1 diabetes mellitus

An acute bout of exercise elicits a rapid, potentially deleterious, reduction in blood glucose in patients with type 1 diabetes mellitus (T1DM). In the current study, we examined whether a 10-week aerobic training program could alleviate the rapid exercise-associated reduction in blood glucose through changes in the glucoregulatory hormonal response or increased hepatic glycogen storage in an insulin-treated rat model of T1DM. Thirty-two male Sprague-Dawley rats were divided evenly into 4 groups: non-T1DM sedentary (C) (n = 8), non-T1DM exercised (CX) (n = 8), T1DM sedentary (D) (n = 8), and T1DM exercised (DX) (n = 8). Exercise training consisted of treadmill running for 5 days/week (1 h, 27 m/min, 6% grade) for 10 weeks. T1DM was induced by multiple streptozotocin injections (20 mg/kg) followed by implantation of subcutaneous insulin pellets. At week 1, an acute exercise bout led to a significant reduction in blood glucose in DX (p < 0.05), whereas CX exhibited an increase in blood glucose (p < 0.05). During acute exercise, serum epinephrine was increased in both DX and CX (p < 0.05), whereas serum glucagon was increased during recovery only in CX (p < 0.01). Following aerobic training in DX, the exercise-mediated reduction in blood glucose remained; however, serum glucagon increased to the same extent as in CX (p < 0.05). DX exhibited significantly less hepatic glycogen (p < 0.001) despite elevations in glycogenic proteins in the liver (p < 0.05). Elevated serum epinephrine and decreased hepatic adrenergic receptor expression were also evident in DX (p < 0.05). In summary, despite aerobic training in DX, abrupt blood glucose reductions and hepatic glycogen deficiencies were evident. These data suggest that sympathetic overactivity may contribute to deficiencies in hepatic glycogen storage.

MSC attenuate diabetes-induced functional impairment in adipocytes via secretion of insulin-like growth factor-1

The function of subcutaneous adipocytes in promoting wound healing is significantly suppressed in diabetic wounds. Recent studies have demonstrated the ability of mesenchymal stem cell (MSC) to ameliorate impaired diabetic wound healing. We hypothesized that MSC function may involve subcutaneous adipocytes. The abnormal function of subcutaneous adipocytes from STZ induced diabetic mice including glucose uptake and free fatty acid (FFA) secretion level were assessed. Then these cells were co-cultured with MSC via a transwell system to observe the changes of metabolic index and glucose transporter four (GLUT4) as well as phosphoinositide 3-kinase/protein kinase (PI3K/AKT) signaling pathway expression. The results of metabolic index suggest that MSC obviously attenuated the diabetes-induced functional impairment. Both mRNA and protein expression analyses showed that PI3K/AKT insulin signaling pathway and GLUT4 expression were up-regulated. These changes were substantially associated with a increased level of insulin-like growth factor-1 (IGF-1) secretion from MSC. These findings suggest that MSC could attenuate abnormal function of diabetic adipocytes by IGF-1secretion, which was more or less associated with the beneficial effects of MSC on improving diabetic wound healing.

Positive effects of aerobic exercise on learning and memory functioning, which correlate with hippocampal IGF-1 increase in adolescent rats

It is already known that regular aerobic exercise during adolescent period improves learning and memory in rats. In this study, we investigated the effects of regular aerobic exercise on learning, memory functioning and IGF-1 levels. IGF-1 is known to have positive effects on cognitive functions in adolescent rats. Exercise group was separated into two different groups. First half was run on a treadmill for 30 min per session at a speed of 8m/min and 0° slope, five times a week for 6 weeks. The second half was given free access to a running wheel (diameter 11.5 cm) which was connected to a digital counter and run on a treadmill for 6 weeks. Learning and memory functioning were found to be positively correlated with the exercise activity. Findings suggest increased neuron density in CA1 hippocampal region and dentate gyrus. Increased IGF-1 level was detected in hippocampus and blood serum, while IGF-1 level in liver tissue did not change with exercise activity. In conclusion, our findings indicate that learning and memory functioning were positively affected by voluntary and involuntary physical exercise which correlated increased hippocampal activity and elevated IGF-1 levels in adolescent rats.

Muscle protein metabolism in neonatal alloxan-administered rats: effects of continuous and intermittent swimming training

BACKGROUND

This study aimed to examine the effects of intermittent and continuous swimming training on muscle protein metabolism in neonatal alloxan-administered rats.

METHODS

Wistar rats were used and divided into six groups: sedentary alloxan (SA), sedentary control (SC), continuous trained alloxan (CA), intermittent trained alloxan (IA), continuous trained control (CC) and intermittent trained control (IC). Alloxan (250 mg/kg body weight) was injected into newborn rats at 6 days of age. The continuous training protocol consisted of 12 weeks of swimming training in individual cylinder tanks while supporting a load that was 5% of body weight; uninterrupted swimming for 1 h/day, five days a week. The intermittent training protocol consisted of 12 weeks of swimming training in individual cylinder tanks while supporting a load that was 15% of body weight; 30 s of activity interrupted by 30 s of rest for a total of 20 min/day, five days a week.

RESULTS

At 28 days, the alloxan animals displayed higher glycemia after glucose overload than the control animals. No differences in insulinemia among the groups were detected. At 120 days, no differences in serum albumin and total protein among the groups were observed. Compared to the other groups, DNA concentrations were higher in the alloxan animals that were subjected to continuous training, whereas the DNA/protein ratio was higher in the alloxan animals that were subjected to intermittent training.

CONCLUSION

It was concluded that continuous and intermittent training sessions were effective in altering muscle growth by hyperplasia and hypertrophy, respectively, in alloxan-administered animals.

Morphology and protein content of hepatocytes in type I diabetic rats submitted to physical exercises

The importance of physical exercise practice in the treatment of diabetes has been reported in many studies recently, but only limited data can be found regarding its benefits on liver morphology and protein content of hepatocytes. In order to assess the changes arising from the development of type I diabetes and the benefits of a training protocol, Wistar rats were divided into four groups: sedentary control (SC), trained control (TC), sedentary diabetic (SD) and trained diabetic (TD). The training protocol consisted of swimming for 60 min a day, 5 days/week, during 8 weeks. Liver samples were collected, processed and analyzed by histochemical and ultrastructural techniques. Biochemical tests were also conducted to examine the protein content and quantity of DNA in the liver. In morphological assessment, the presence of areas of cytoplasmic basophilia observed in control subjects was not visualized in sedentary diabetics. It was related to differences in the amount of mitochondria in the cytosol. The mitochondrial structure has not undergone relevant changes, and the number of rough endoplasmic reticulum cisterns was clearly inferior in sedentary diabetics, suggesting lower protein production. However, the biochemical analysis of protein content indicated no statistical differences between groups. The exercise, in turn, was not responsible for major changes in these characteristics. On the whole, the morphological damages arising from type I diabetes were noteworthy. Nevertheless, regular physical training was not responsible for significant improvements in some respects, making evident the need for combined application of a distinct form of treatment.

Effects of physical training on serum and pituitary growth hormone contents in diabetic rats

The present study investigated the effects of moderate physical training on some of the parameters in the GH-IGF axis in experimental diabetic rats. Male Wistar rats were allocated into the following groups: sedentary control, trained control, sedentary diabetic, trained diabetic. Diabetes was induced by alloxan (32 mg/kg, b.w. iv). The physical training protocol consisted of 1 h swimming session/day, 5 days/week for 8 weeks supporting a load corresponding to 90% of maximal lactate steady state. After the experimental period, blood was collected to measure serum glucose, insulin, triglycerides, albumin, insulin-like growth factors-I (IGF-I), and growth hormone (GH). Pituitary gland was removed for GH quantification. Diabetes increased blood glucose and triglycerides and decreased insulin, IGF-I, serum and pituitary GH. Physical training decreased glucose and triglycerides, and also counteracted the reduction of serum IGF-I in diabetic rats. In conclusion, physical training recovered serum IGF-I showing no alteration of serum or pituitary GH levels.