فصلنامه فیزیولوژی ورزشی
پیاپی 48 (زمستان 1399)

The purpose of this study was to investigate the effect of 8 weeks aerobic exercise on the expression of LXRa, PEPCK and G6PC2 mRNA in the liver tissue of obese prediabetic mice. 18 male C57BL/6 mice were divided into two groups: 1. Mice fed a high-fat diet (prediabetic obese mice) (n=12), 2. Mice fed a standard diet (non-obese mice) (n= 6). Prediabetic conditions were confirmed by glucose tolerance test (GTT). Then, prediabetic mice were randomly divided into two groups: the high-fat diet-Exercised (HFD-Exe) and the high-fat diet-Sedentary (HFD-Sed). Exercise group were trained on a motor-driven treadmill at 21 m/min, 45 min/day, 5 days/week for 8 weeks. Mice were sacrificed 24 hours after last exercise session and blood was taken from the heart. The liver tissue was isolated and frozen to measure of LXRa and ABCA1 expression levels and was kept at -70 ̊C.Data indicated that the levels of liver LXRa and ABCA1 in trained mice were significantly higher than in untrained mice.The relative expression of key genes in gluconeogenesis, including G6PC2 and PEPCK in the liver of trained mice, was significantly reduced compared to untrained group. Also, aerobic exercise reduced steatosis and the liver enzymes in prediabetic mice.Following physical exercise, the expression of LXRa and ABCA1 mRNA expression in the liver of mice increases and protects mice from high-fat diet induced obesity and reduces the risk of NAFLD.

The aim of this study was to investigate the effects of HIIT and curcumin supplementation on cardiac tissue caspase 3 content and also expression of miR-1 and miR-133 in rats exposed to arsenic. Forty-eight (age: 16 weeks, weight: 340.31 ± 24.77 gr) male rats were randomized into six groups including on Arsenic-Training (HIIT), Arsenic-Curcumin (Curcumin), Arsenic – Training + Curcumin (Concomitant), Arsenic (Arsenic), Ethanol Control and Normal Control (pure water). Arsenic 5 mg/bw.day and Curcumin 15 mg/bw.day were consumed orally for six weeks. HIIT were conducted for six weeks (5 d/w) including on 60 min interval running/session (each interval bout was consisted of 4 min running at 85-90% of v Vo2max with 2 min recovery between work intervals at 50-60% of v Vo2max). Cardiac Caspase 3 and miRNAs expression levels were evaluated by western blot and RT-PCR analysis methods respectively. Cardiac mir-1 expression level (P=0.001) and also caspase 3 content (P=0.001) were higher, however; mir-133 expression level was lower (P=0.001) in the Arsenic group than the Normal Control. While no differences were observed in miR-1(P=0.20) and miR-133 (P=0.45) expressions as well as caspase 3 content (P=0.26) between the HIIT and Arsenic groups; lower caspase 3 content was observed in Curcumin group than the Arsenic counterparts (P=0.001). However, in Concomitant group, there were a lower mir-1 expression (P=0.042) and caspase 3 content (P=0.001) in accompany with a higher mir-133 (P=0.010) expression compared to the Arsenic group. Arsenic exposure predisposes cardiomyocytes to apoptosis via modifications in both miR-1 and miR-133 expressions which is associated with cardiac diseases. While physical training could not fully overcome arsenic toxicity in cardiomyocytes, curcumin supplementation and mostly the concomitant effect have more benefits. However, more research warranted to be done because of the lack of similar evidence and also limitations in this study.

Time of playing (Competition) may be affected by the maturity level, hormonal indices as well as the level of physical fitness of adolescent players, therefore the present study, with the purpose of this study is to determine and correlate the maturity, functional and hormonal indices with the time of playing (Competition) in elite football players. Thirty-one elite youth soccer players with a mean age of 16.51±0.252 years were studied over the football season then, the time of playing (Competition) of player was registered. At the end of the season, anthropometric characteristics, hormonal (GH, IGF-1) indices by chemiluminescence, maturity status by skeletal age, fitness tests (CMJ, 7RST, and Yo-Yo Test) Were measured. Pearson and Spearman correlation methods were used to specify the relationship between variables and multiple linear regression to explain the time of playing (Competition) of players (p < 0.05). The results of correlation between variables showed that time of playing with VO2max (r = 0.56), skeletal age (p = -0.42), CMJ (r = 0.40), maturity offset (r = -0.38) And IGF-1 (r = 0.36) had a significant relationship. Multiple linear regression analysis with R2=0.55 was significantly predicted players' time of playing (Competition). The results of the present study showed that high levels of insulin-like growth hormone and VO2max play a preponderant role in selecting and minutes of playing (Competition) of players in competitions. However, it appears to be more pragmatic to consider other contextual dimensions, as they can impact time of playing (Competition) in a match.

Studies show that exercise training and bioactive component of saffron can reduce apoptosis and cachexia caused by cancer. The present study aimed to investigate the effects of four weeks of high-intensity interval training (HIIT) and consumption of saffron aqueous extract (SAE) on the expression of some cachexia-related genes (SIRT1, hTERT, and p53) in the gastrocnemius muscle of mice carrying 4T1 breast cancer cell line. For this purpose, 44 female BALB/c mice were randomly divided into HIIT, SAE, HIIT + SAE, control and sham groups. Following 48h of the last intervention session, mice were euthanized, and the gastrocnemius muscle removed for further analyses. The results showed that the expression of the SIRT-1 gene in the HIIT group was significantly higher than the control and SAE + HIIT groups (P=0.03 and P=0.02, respectively). Also, the gene expression of hTERT in the HIIT group was significantly higher than the other groups (p < 0.05) and in the SAE group was significantly higher than the SAE + HIIT group (P=0.01). Furthermore, the gene expression of p53 in the HIIT and SAE + HIIT groups was lower than the SAE group (P=0.003 and P=0.004, respectively). Based on the results, it seems that HIIT has a positive role in reducing cancer-induced cachexia by regulating higher expression of SIRT1 and hTERT and lower expression of p53 and may be effective in reducing cancer-induced muscle wasting.

The toxic effects of Doxorubicin on various tissues from one hand, and the pre-treatment effects of exercise activity before the DOX induction on heart and liver tissues in young rats from other hand have already been recognized, but the pre-treatment effects of exercise on elderly rats, especially in the lung tissue is not well understood. The purpose of the present study was to compare changes in lung tissue following DOX intoxication and the preventive effect of aerobic exercise. 48 young (3 months) and elderly (32 months) male rats were divided into three subgroups: control (307.8, 374.8), DOX (422.368, 430) and DOX + exercise (372.370, 383). Training groups r an on treadmill for three weeks at a speed of 15-17 m/min and a time of 25-39 minutes and five sessions per week.  DOX receiver groups received DOX solution (20 mg / kg) 24 hours after the last exercise. 48 hours after DOX injection, biopsy and descriptive analysis were performed. Histological examination of lung tissue showed inflammation, intercellular edema, vascular congestion, increased vascular wall thickness in DOX induction groups and with more degradation in the elderly groups. Performing aerobic exercise pre-treatment in both groups improved the injuries caused by DOX. The findings showed that induction of DOX caused more damage to the lung tissue of elderly rats than young rats, because the resistance of elderly lung tissue to DOX was lower and pre-treatment with aerobic exercise mitigated the destructive effect of DOX on lung tissue and this healing is more evident in elderly lungs.

The use of nanoparticles is increasing and can cause neurotoxicity and brain tissue changes. On the other hand, pre-conditioning improves neuronal protections. Therefore, the aim of this study was to investigate the structural changes in brain tissue following Nano silver injections following the two protocols. 30 male Wistar rats were divided in 6 groups of healthy control, nano silver, aerobic protocol, anaerobic protocol, nano silver + aerobic protocol, nano silver + anaerobic protocol. Intraperitoneal injection of nano silver after 10 weeks of aerobic and anaerobic treatments was performed 10% of each rat's body weight in 5 turns. After 48 hours of the last infusion, the rats were indifferent and sampled. The samples were then photographed and stained with Hematoxylin-Eosin and were studied by optical microscopy. The results of this study indicated that pre-conditioning had a significant effect on weight (P = 0.045) and distance traveled in progressive endurance test (P = 0.000). Nanosilver also caused inflammation (P = 0.000) and neuron degeneration (P = 0.000) of brain tissue in nanosilver rats. However, in the training groups, inflammation (P = 0.001) and degeneration (P = 0.001) were reduced, although there was no significant difference between the protocols in degeneration (P = 0.875) and inflammation (P = 0.928). It seems that pre-conditioning of exercise can be effective in reducing the degree of degradation of brain tissue due to the use of silver nanoparticles.