فصلنامه علوم زیستی ورزشی
پیاپی 40 (بهار 1398)

Angiogenesis is a vital process in growth and development of tissues, especially muscle tissues that is affected by muscle contraction. Different training modalities can affect the balance between angiogenic and angiostatic factors. Therefore, the aim of this study was to investigate the effect of 8 weeks of aerobic and resistance training on vascular endothelial growth factor (VEGF) and endostatin (ES) in sedentary women. 30 sedentary women were randomly assigned to 3 groups: aerobic, resistance and control. Resistance training was performed for 8 weeks, 3 sessions per week and three 10-repetiton sets with intensity of 60-70% of 1RM for 9 movements. Aerobic training was performed for 8 weeks, 3 sessions per week, 30 minutes each session with intensity of 65-70% of maximum heart rate. Blood samples were collected 48 hours before and after the last training session in the fasting state. VEGF and ES values were measured using ELISA kit. Data were analyzed by dependent t test and ANOVA at (P<0.05). Intra-group results showed that aerobic and resistance training significantly increased serum levels of VEGF and significantly decreased ES. Also, the results of ANOVA and Tukey post hoc test revealed no significant difference in the amounts of VEGF and ES between resistance and aerobic training (P>0.05). The results of this study showed that resistance training could have the same effects as endurance training in the control and positive balance of angiogenesis

The aim of this study was to investigate the effect of exercise training intensity on cardiac regeneration capacity in rats with myocardial infarction (MI). Male wistar rats were exposed to LAD coronary artery ligation surgery and then the creation of MI was confirmed by echocardiography. Four weeks after surgery, the rats with MI were randomly assigned to these groups: low intensity training (LIT), moderate intensity training (MIT), high intensity training (HIT), and Sham, plus a healthy control group (Con). Training groups performed the exercise training protocols for 6 weeks, 5 sessions per week. The rats were sacrificed after the exercise training intervention, and the obtained data were analyzed by one-way ANOVA and LSD test. The results showed a significant difference in the values of ejection fraction, fractional shortening, mRNA Gata4, and mRNA Tbx5 among all groups (P=0.001). LSD test results demonstrated that ejection fraction and fractional shortening values increased significantly in all three exercise training groups compared with the sham group. However, contrary to this increase, their values in the Con group was significantly higher than the groups with MI. Results also showed that mRNA Gata4 value significantly increased in the LIT group compared with the MIT, HIT, Sham, and Con groups. However, mRNA Tbx5 values showed no significant changes among the groups with MI. Only mRNA Tbx5 values in Con group were significantly higher compared with the groups with MI. In conclusion, regardless the intensity, exercise training increases cardiovascular function in rats with MI. However, it seems that low intensity exercise is a more effective agent in increasing cardiac regeneration capacity in rats with MI.

The aim of this study was to compare the effect of 12 weeks of interval training with high and moderate intensity on perilipin 3 (PLIN3) of visceral adipose tissue and insulin resistance in type 2 diabetic male rats. In this study, 24 male rats with type 2 diabetes were randomly divided into three groups: interval training with moderate intensity (MIIT), interval training with high intensity (HIIT) and control. Interval training (HIIT, MIIT) was applied for 12 weeks, 5 sessions per week. The MIIT protocol included 13 four-min. bouts of activity with intensity of 65-70% vo2max and the HIIT protocol included 10 four-min. bouts of activity with intensity of 85-90% vo2max with 2-minute active rest periods. Western Blot method was used to measure PLIN3 protein levels. ANOVA and Tukey's test were used for data analysis. The results indicated a significant decrease in PLIN3 in the HIIT and MIIT groups compared with the control group (P=0.001). However, there was no significant difference between the training groups (P=0.274). Also, both HIIT and MIIT protocols significantly decreased serum levels of glucose (P=0.001), while they had no significant effects on serum insulin and insulin resistance (P˃0.05). There was no significant difference between training groups in insulin, glucose and insulin resistance changes (P˃0.05). The findings of this study showed that both HIIT and MIIT protocols drastically reduced PLIN3 of visceral adipose and improved glucose metabolism in type 2 diabetic rats. Therefore, it seems that PLIN3 changes in visceral adipose are independent of the training intensity.

Interval training may challenge the protective effect of heart against cell death. However, the protective role of exercise in preventing apoptosis is unknown. The aim of this study was to investigate the effect of high intensity interval training on apoptosis in young rats’ heart. 30 male young Wistar rats were randomly divided into three groups. The training program included six weeks of interval training, six sessions per week, 30 minutes each session with the speed of 25-70 m/min. with 10 one-minute repetitions and 2-minute active rest. Sampling of the heart tissue was conducted 48 hours after the last training session. In order to investigate the apoptosis, the heart tissue was placed in 10% formalin fixative solution. The apoptotic cells were labeled with non-radioactive method. The one-way ANOVA and Bonferroni post hoc test at the significance level (P≤0.005) were used for data analysis. Immunohistochemistry results showed that 6 weeks of HIIT significantly increased 320 and 200% (P≤0.001) of apoptosis in experimental group compared with the 6-week control group and baseline group. These findings delineate a novel, age‐dependent interaction which activated apoptotic pathway by HITT, but such reaction is unclear in adolescents and children and further research is needed. Thus it is necessary to consider training concerns when designing HITT for them.

The aim of this study was to determine the effect of four weeks of voluntary running on running wheel (RW) in adolescence on depression and its effect on oxidative stress in the cerebellum. For this purpose, 24 male rats were randomly divided into 3 groups: control, separated from mother (MS) and separated from mother and running wheel (MS + RW). MS and MS + RW rats were separated from their mothers from postnatal day (PND) 2 to 14 for 180 min. per day. Then, each 4 rats per cage were kept until the 28th day. MS + RW group had access to the running wheel 24 hours a day from the 28th day. At PND 60, depressive-like behaviors were assessed by Open Field Test (OPT), Sucrose Preference Test (SPT), Forced Swimming Test (FST) and Splash test. Biomarker of oxidative stress including mitochondrial reactive oxygen species (ROS) in the cerebellum tissue was also measured. The results showed that voluntary running significantly neutralized depression-like behaviors induced by the maternal separation stress and reduced oxidative stress. Also, the results showed that voluntary running could be useful as a non-pharmacological treatment for depression.

The vanilloid receptor 1 (TRPV1) is a nociceptor receptor in sensitive system which is activated by capsaicin, heat, acidity and some metabolites. The role of this cation receptor is known at pain. New reports suggest that TRPV1 plays a role in other processes and researchers are studying the effect of this receptor on exercise pressure reflex (EPR) and cardiovascular response in some diseases.  In this experimental study, the aim of this study was to find an appropriate answer to perceive the effect of moderate continuous training on the expression of TRPV1 protein in soleus muscle. 16 male Wistar rats (weight: 200-220 gr) were randomly assigned to 2 groups: training and control. The training group performed 6 weeks (5 sessions per week) of moderate continuous training. The control group did not have any training but there was no difference between these groups in all conditions. The rats were anesthetized, sacrificed and their required tissues were extracted by standard procedures. The results of independent t test derived from Western Blotting laboratory findings for TRPV1 receptor protein expression showed a significant increase (P=0.033) in the expression of this receptor in soleus muscle in the training group compared with the control group. These results show that sensory nerves are adapted to training with an increase in TRPV1 receptor protein expression.

The aim of this study was to find answers to these questions: can exercise increase neurogenesis and does neurotrophic factor that is necessary for neurogenesis increase with training?30 rats were divided into four groups: young control, young training, middle-aged control and middle-aged training. The training was performed with overload principle for 6 weeks and 6 sessions per week. Young rats ran with the speed of 27 m/min. and the middle-aged rats with the speed of 20 m/min. for 20 minutes on the first day. The running time increased 2 minutes every day until it reached 60 minutes per day. Elisa method was used to measure the factors and they were analyzed by Tukey post hoc test.There was no significant difference in weight between young groups (sig=0.979) but the difference was significant between middle-aged groups (sig=0.000). Ki67 in young and middle-aged training groups was significantly more than control group (sig=0.002) and (sig=0.037). Midkine did not have a significant increase in the young training group compared with the young control group (sig=0.134). This factor increased in middle-aged training group but this increase was not significant (sig=0.557). The correlation between ki67 and Midkine was significant (r=0.407) (sig=0.029).Continuous training can increase the neurogenesis in young and middle-aged rats. This type of training may be useful to increase neurogenesis and its essentials (i.e. neurotrophic factors).

Diabetes is associated with increased lipogenesis and expression of lipogenic genes in the liver, and neuregulin-4 activity is associated with inhibition of liver lipogenesis. The aim of this study was to investigate the effect of 4 weeks of aerobic exercise on changes of serum and liver levels of neuregulin-4and lipid profile in diabetic rats. 32 male adult rats were randomly divided into healthy control, control diabetic, exercise and exercise diabetic groups (each group 8 rats). Diabetes was induced by intraperitoneal injection of streptozotocin solution (55 mg/kg). The exercise was performed for 4 weeks, 5 sessions per week, at speeds of 15 to 18 m/min. and for 25 to 44 minutes. 48 hours after the last exercise session, blood samples were collected and liver tissue was removed and Neuregulin-4 levels were measured. The results showed no difference in serum and liver levels of neuregulin-4 between diabetic and healthy groups (P>0.05). Serum levels of cholesterol and HDL were not significantly different among the above groups (P>0.05). Triglyceride and LDL were significantly higher among these groups (P<0.05). 4 weeks of aerobic exercise did not affect serum and liver levels of neuregulin-4 in diabetic and healthy rats (P>0.05). Also, 4 weeks of aerobic exercise did not affect serum levels of cholesterol, triglyceride, HDL and LDL in healthy rats (P>0.05). Exercise in diabetic rats significantly decreased serum levels of cholesterol and triglyceride (P<0.05) but it did not make any significant differences in HDL and LDL (P>0.05). Although the levels of lipid profile changed significantly,  4 weeks of aerobic exercise probably cannot stimulate increases of neuregulin-4 in serum and liver tissue.