Journal of Sport Biosciences
Year:2018 | Volume:10 | Issue:1|Papers Count:10

Diabetic cardiomyopathy (DCM) is one of the most important complications of diabetes and is one of the major causes of death in diabetic patients. DCM at the molecular level is rooted in down regulation of expression or activity of those various proteins involved in maintenance or regulation of intracellular calcium homeostasis. The aim of this study was to investigate the effect of 4 weeks of high intensity interval training (HIIT) on gene expression of calcium channel of ryanodine receptors (RyR2), SERCA2a and phospholamban (PLB) in the heart of diabetic male rats. In this experimental study, 24 male Wistar rats were divided into two groups: sedentary control and HIIT. Diabetes was induced in both groups by intraperitoneal injection of Streptozotocin (STZ) solution. 24 hours after the last training session, the rats were euthanized and their left ventricle was extracted. Real Time-PCR technique was used to determine the gene expression of RyR2, SERCA2a and PLB. To compare the two groups, independent t test was used at alpha level of 0. 05. The results revealed that 4 weeks of HIIT significantly increased gene expression of RyR2 in the left ventricle of the heart of HIIT group (P=0. 03). Although gene expression of SERCA2a and phospholamban increased, they were not significantly different. Based on these findings, it can be concluded that 4 weeks of HIIT could prevent and minimize the maladjustments in these 2 proteins affecting cycle of cardiac contraction and reduce the risk of diabetic cardiomyopathy through increased RyR2 gene expression in the heart of diabetic rats.

The vascular endothelial growth factor receptor (VEGFR-2) has the most potent angiogenic signaling associated with VEGF. So far no research has been published on the effect of training on VEGFR-2 and the vascular volume in the lungs. Therefore, the aim of the present study was to investigate the effect of high intensity interval training on VEGFR-2 expression and pulmonary vascular volume in male Wistar rats. In this experimental study, the sample included 10 male Wistar rats and were randomly and equally divided into training and control groups. The rats started the training program with the speed of 25 meters per minute and finished with 70 meters per minute during 6 weeks. Each training session included 10 one-min. repetitions with 2-min. rest intervals. In the end, lung tissue was extracted for stereological and immunohistochemistry tests. Statistical analysis with independent t test and Pearson correlation coefficient showed a significant increase in VEGFR-2(sig: 0. 001) and pulmonary vascular volume (sig: 0. 042) in the training group compared with the control group, and a positive and almost strong relationship between changes in these two indicators and training (sig: 0. 035). In general, it seems that 6 weeks of high intensity interval training has the potential to promote of lung pro-angiogenic processes.

The aim of this study was to investigate four weeks of high intensity interval training on gene expression of muscle myonectin and insulin resistance in male adult Wistar rats. 14 male adult Wistar rats (age: 8 weeks and mean weight: 206. 12± 9) were randomly divided into two groups: interval training and control (each group 7 subjects). Animals in training group received 4 weeks of high intensity interval training on a treadmill (5 sessions per week, the speed of 35 to 55 meters / minute from first week to last week in 10 steps for one minute and 2-minute rest intervals) while the control group did not have any training. The homogenated soleus muscle and the gene expression of myonectin were measured by Real-time PCR analysis. The ELISA method was used to measure insulin and glucose levels were measured by glucose oxidase method. The data were analyzed by independent t test at P<0. 05. The results showed that a significant increase in myonectin gene expression in training group compared with the control group after 4 weeks of training (P=0. 012). The difference in insulin resistance index was not significant between the groups after 4 weeks of training (%23 difference between the groups) (P=0. 362). According to these results, it seems that training can play a role in regulating and improving the body metabolism through making a positive adjustment with an increase in myonectin expression.

The effect of physical activity and changes in phenotype of white adipose tissue is a new issue and the controversial results and molecular mechanisms suggested for it are investigated. Resveratrol supplement has received attention as a factor which increases fat metabolism in adipose tissue. The aim of this study was to determine the effect of resveratrol supplementation and aerobic training on protein levels of SIRT-1, PGC-1α and UCP-1 in liver tissue, abdominal-inguinal adipose tissue and subcutaneous adipose tissue in male rats. In this study, 28 male rats (mean weight: 260+10 gr, age: 8 weeks) were randomly divided into 4 groups: control (C), aerobic training (T), supplement-training (T-R) and supplement (S). Training groups exercised for 14 weeks (5 sessions a week, 45 minutes each session) on a treadmill. TR group daily received resveratrol supplement (10mg/kg of body weight). The ELISA method (double-sandwich) was used to measure tissue proteins of UCP-1, SIRT1 and PGC-1α . One-way ANOVA test was used for data analysis and statistical significance was considered as P≤ 0. 05. SIRT1 and PGC-1α proteins changed in liver tissue and subcutaneous / visceral white adipose tissue as P≤ 0. 05 and P≤ 0. 001 respectively. UCP-1 protein significantly increased in the measured tissues in T-R group after supplement in combination with aerobic training (P≤ 0. 001). According to these results, supplementation may improve liver function and change phenotype of subcutaneous white adipose tissue to beige (intermediate) adipose tissue.

The aim of the present study was to compare the sympathetic neural and endothelial responses of brachial artery to vasodilatory and constrictor stimuli in elite weightlifters and a sedentary age-matched control group. 7 elite weightlifters (age 23. 5± 2. 2 yrs) and 8 sedentary healthy subjects (age 24. 3± 2. 12 yrs) voluntarily participated in this study. High-resolution Doppler ultrasound was used to determine brachial artery diameters at rest, following 5 minutes of forearm occlusion [Flow Mediated Dilation (FMD)] and during acute sympathetic stimulation [cold pressure test (CPT)]. Vasoreactivity responses were calculated from the vasodilatory and constrictor peak changes in artery diameter. The acquired data were analyzed using independent t test and repeated measures method at P≤ 0. 05. Brachial artery diameters in baseline [mean differences, 0. 5 mm (P=0. 001)], peak vasodilation [mean differences, 0. 57 mm (P=0. 002)] and peak constriction [mean differences, 0. 498 mm (P=0. 003)] were significantly greater in weightlifters than control group. However, no significant difference was observed in %FMD, %CPT and vascular operating range (VOR) between weightlifters and age-matched control group (P≤ 0. 05). The present study indicated that the function of brachial artery is not necessarily enhanced in elite weightlifters. However, elite weightlifters had larger brachial artery diameter than age-matched healthy control subjects.

The effect of chronic and acute exercise training has been investigated as a vaccine adjuvant in some studies. The aim of this study was to assess adjuvant effects of short term endurance training on activation of regulatory T cells in HSV-1 vaccine model. 24 BALB/C mice were divided into 3 groups: control, vaccine and vaccine plus short term endurance training. The activation of reglulatory T cells was determined after spleen cell culture with ELISA method. One-way ANOVA was used for data analysis. The results indicated a significant difference among the groups in reglulatory T cells activation (P<0. 05). Tukey post hoc test results showed a significant difference between control and vaccine groups with vaccine plus short term endurance training group (P<0. 05). Results of the current study showed that increased reglulatory T cells activation following short term endurance training was considered as an adjuvant. These results suggested that short term endurance training as an adjuvant may enhance vaccine efficacy.

Resistance exercises increase oxidative stress and muscle damage. The aim of the present study was to investigate the effect of vitamin D on MDA and CK changes during 8 weeks of progressive resistance training. 40 male subjects (age range 20-25 years) participated in the study voluntarily and were randomly assigned to 4 groups: vitamin D-resistance training (RTD; n=10), placebo-resistance training (RTP; n=10), vitamin D (VD; n=10) and control (con; n=10). Progressive resistance training was performed 3 sessions a week, every other day for 8 weeks with eight movements and increased intensity. Subjects in RTD and VD groups consumed a 50000-IU capsule of vitamin D every two weeks. Blood samples were gathered before and after the training period. Plasma was used to assess CK activity and MDA concentration. Results showed no significant difference among the groups in CK (P˃ 0. 05). However, it was observed that MDA changes in group x time interaction was significant (P=0. 001), that is to say MDA concentration significantly decreased in RTD group compared with VD (P=0. 017) and control (P=0. 034) groups. Also, MDA concentration was significantly lower in RTP than VD in the posttest (P=0. 045). However, there was no significant difference between RTD and RTP. Finally, it can be said that the combination of resistance training and vitamin D can decrease lipid peroxidation. However, it seems that resistance training role is very important in this regard.

Considering the epidemic dimensions of obesity in the world, negative energy balance methods can play a critical role in public health. The aim of the present study was to investigate the effect of 10 weeks of aerobic training and unsaturated high fat diet on serum levels of adiponectin in obese male rats. Blood samples were collected from 48 Wistar male rats (mean weight 195± 5 g, age 8 weeks) at 1st, 18th and 28th weeks after overnight fasting. After baseline sampling, remaining 40 rats were randomly divided into control (n=16) and high-fat-diet (n=24) groups. High-fat-diet group were randomly divided into exercise training and high-fat-diet subgroups after 18 weeks. Exercise training group received aerobic training for 10 weeks (5 sessions/week) with an intensity of 70-75% VO2max. Serum concentrations of total adiponectin and HMW as well as lipid profile and glycemic indexes were measured. The results indicated that aerobic training in high-fat-diet group significantly increased serum levels of total adiponectin in comparison with high-fat-diet control group (P<0. 01). Also, all glycemic indexes, total cholesterol, LDL-C and triglyceride decreased in aerobic training compared with high-fat-diet group (P<0. 05). This study indicated that aerobic training could increase serum levels of total adiponectin in obese rats even with unsaturated high fat diet and improve lipid and metabolic profiles.

Neurotrophins mediate the effects of physical activity on brain health and function. The aim of this study was to investigate the effect of aerobic exercise in the form of treadmill running with and without carbohydrate supplementation on serum levels of BDNF, NT-3, NT-4 and IGF-1. In this semi-experimental study, 12 beginner adolescent male futsal players in Khorramabad city (age: 17. 13± 0. 64 years; weight: 64. 25± 10. 18 kg; height: 172. 88± 5. 59 cm) were voluntarily selected. Subjects performed 1 hour of running with moderate intensity (60% of heart rate reserve) in two sessions with carbohydrate supplementation or placebo in a randomized cross-over design. Blood samples were obtained before the first session and 5 min. after sessions. The serum levels of BDNF, NT-3, NT-4 and IGF-1 were measured using an ELISA kit. Data were analyzed by repeated measures test and the level of significance was set at P<0. 05. The results showed that 1 hour of treadmill running with and without supplementation could significantly increase serum levels of BDNF, NT-3 and NT-4 compared with the baseline (P<0. 05). Despite more increase in BDNF, NT-3 and NT-4 during supplementation, there was no significant difference between supplementation and placebo (P>0. 05). Also, serum levels of IGF-1 did not change (P=0. 099). One hour of aerobic exercise with moderate intensity with and without carbohydrate supplementation equally increased serum BDNF, NT-3 and NT-4 significantly. Therefore, it seems that duration/intensity of exercise or both or concentration of carbohydrate should increase in order to increase the effects of carbohydrate supplementation on serum levels of neurotrophins.

Little information is available about the effects of high intensity aerobic training (HIT) and arginine supplementation on appetite regulating hormones along with nutritional control in obese adolescents. The aim of this study was to investigate the effect of 8 weeks of high intensity aerobic training and arginine supplementation on hormonal changes in leptin and agouti-related protein (AGRP) in obese adolescent boys. In isoenergetic conditions, 20 obese adolescents were divided into two groups based on their aerobic power: 1) HIT and placebo (n=10) and HIT and arginine supplementation (n=10). Before intervention of exercise protocol and 48 hours after the last training session, levels of appetite regulating hormones in blood were measured by Enzyme-Linked Immunoassay (ELISA) method. Paired sample t test and ANCOVA were used to analyze the intra-group and intergroup differences respectively. The results showed that despite a significant intra-group and intergroup reduction in body weight and body fat present (P≤ 0. 05), the intra-group and intergroup changes of leptin and AGRP were not significant compared with the baseline in HIT and placebo as well as HIT and arginine supplementation groups (P≥ 0. 05). 8 weeks of arginine supplementation and HIT reduced body weight and body fat percent in obese adolescents more than HIT alone, but none of these protocols affected appetite regulatory hormones.