Effects of a 4-week plyometric training on activity patterns during different phases of one-leg drop jump with focus on jump height.

Athletic women have shown a higher risk of ACL injury during jump landing compared to men. Plyometric training can be an alternative way to minimize the risk of knee injuries via the changed muscle activity patterns. Hence, the aim of this study was to determine the effects of a 4-week plyometric training program on the muscle activity pattern in different phases of one-leg drop jump in active girls. Active girls were randomly allocated into 2 groups (Plyometric training = 10, Control group = 10) where the plyometric training group (PTG) performed 60 min exercises, 2 sessions/1 week for 4 weeks while the control group (CG) had their daily activity. In the pre to post test, the sEMG was recorded from the Rectus Femoris (RF), Biceps Femoris (BF), Medial Gastrocnemius (GaM), and Tibialis Anterior (TA) muscles of the dominant leg during the Preparatory phase (PP), Contact Phase (CP), Flight Phase (FP) of one-leg drop jump. Electromyography variables (Signal amplitude, Maximum activity, Time to peak (TTP), Onset and activity time and Order muscle activity) and Ergo jump variables (Time of preparatory phase (TPP), Time of contact phase (TCP), Time of flight (jump height) phase (TFP), and Explosive power were analyzed. The Univariate ANCOVA test showed a significant difference between the two groups in Activity Time, whilst adjusting for pre-test as a Covariate, only in TA muscle (F(1,17) = 5.09, p = 0.038, η2 = 0.230). In PTG. TA (- 15%), GaM (- 19%), and BF muscles (- 9%) started their activity earlier while there was no significant difference between the two groups at the Onset time. TTP of RF was significantly different between the 2 groups only in the PR phase (0.216 ± 0.07 vs 0.153 ± 0.09 s) (p = 0.049, 95% CI = 0.001, 0.127). Results of the present study suggest that a 4-week plyometric training can improve the stability of leg joints via earlier recruitment of muscles and change activity patterns in lower limb muscles. It also recommends that the preparatory phase before landing be considered an important stage in preventing sports injuries in a training program.

Non-local muscle fatigue is mediated at spinal and supraspinal levels.

The objective was to measure the corticospinal excitability and motoneuron responsiveness of the right and left Biceps Brachii (BB), and left Abductor Digiti Minimi (ADM) muscles in response to submaximal isotonic fatiguing contractions performed by the right BB muscle. With the familiarization session, ten young moderately active male subjects came to the lab on seven occasions. Three sets of 3 min seated elbow curls at 25% of one-repetition maximum (1RM) separated by a 1-min rest performed by the right BB muscle were used as the fatiguing protocol. The motor evoked potential (MEP), cervicomedullary motor evoked potential (CMEP), and compound muscle action potential (Mmax) of the right BB muscle (baseline and after each set of the fatiguing task), the left BB and ADM muscles (baseline, post-fatigue, post-10, and post-20 min) were measured. MEP and CMEP were then normalized to Mmax for statistical analysis. The results showed that in the right BB muscle, there was a significant reduction in the MEP after performing the fatiguing task (p= 0.03), while no significant effect of time was seen in the CMEP (p= 0.07). In the left BB muscle, the MEP significantly decreased from pre-fatigue to post-fatigue (p= 0.01) and post-10 (p= 0.001), while there was a significant decline in the CMEP post-fatigue (p= 0.03). In the left ADM muscle, MEP significantly decreased post-fatigue (p= 0.03) and no changes were seen in the CMEP (p= 0.12). These results not only confirm the incidence of non-local muscle fatigue (NLMF) in response to performing submaximal isotonic fatiguing contractions but also as a new finding, imply that both spinal and supraspinal modulations account for the NLMF response.

The effect of 4-Week rehabilitation by aerobic exercise on hippocampus BDNF and TGF-ß1 gene expressions inAß 1-42-induced rat model of Alzheimer's disease.

Alzheimer's disease (AD) is a type of brain dysfunction featuring a gradual loss in memory. This study aimed to determine the effect of 4 weeks of aerobic rehabilitation exercise (RhExe) on the genes expression of BDNF and TGF-ß1 in the hippocampus tissue of rats with the AD induced by injection of amyloid-beta (Aß1-42). Twenty-one male Wistar rats were randomly divided into 3 groups: Aß injection (n = 7), Aß + exercise (n = 7) and control (n = 7). AD was induced by a single dose of Aß injection into the hippocampus of rats. Three days after surgery, the Aß + exercise group experienced four weeks of the RhExe (5 days/week). Forty-eight hours after the last training session, the animals underwent the Morris water maze test. The animals were sacrificed 24 h after the test, and hippocampal tissue was split. The mRNA expression of BDNF, TGF-ß1, and TGF-ß1 II receptors was measured. The TGF-ß1 and TGF-ß1 II receptor genes expression of Aß + exercise group were significantly higher than the Aß injection group (P ≤ 0.001). BDNF gene expression in the hippocampus of the Aß + exercise group was significantly higher than the Aß injection group (P ≤ 0.001). Spatial memory was significantly higher in the Aß + exercise group than in the Aß injection group (p ≤ 0.01). It seems that aerobic exercise can counteract the harmful effects of Aß through the BDNF and TGF-ß1molecular signaling pathways.

Monitoring training in women's volleyball: Supine or seated heart rate variability?

We aimed to examine changes in resting heart rate variability, submaximal exercising heart rate (HRex), countermovement-jump height (CMJ), perceptual wellbeing, and internal load throughout preparatory training in elite women's volleyball players. We also aimed to determine which HRV measurement position (supine vs. seated) provided greater associations with the various markers of training adaptation. Thirteen players (age = 25.8 ± 3.0 years, height = 178.1 ± 6.7 cm, weight = 69.7 ± 7.6 kg) were monitored throughout four successive training camps preceding the Asia Cup. Daily measures of the root-mean square of successive differences were used to calculate the mean (LnRMSSDM) and coefficient of variation (LnRMSSDCV) for each camp. Averages were also determined for Hooper's Index and session ratings of perceived exertion (sRPE). HRex and CMJ were tested at the start of each camp. RESULTS: Seated LnRMSSDCV, HRex, CMJ, and sRPE increased at camp 3 (p < 0.05), then reverted to values similar to camp 2. Changes in seated LnRMSSDM were associated with changes in HRex (r = -0.68 to -0.71, p < 0.05). Occasional associations (p < 0.05) were observed between LnRMSSDCV and Hooper's Index (r = 0.59) and CMJ (r = -0.57), and changes in HRex (r = 0.69) and HRR (r = -0.62). CONCLUSIONS: A reduced cardiorespiratory response to a standardized submaximal workload was associated with increased seated LnRMSSDM. Higher seated LnRMSSDCV was observed in response to increased sRPE and was often associated with decrements in various status markers. Seated LnRMSSD provided more associations with indicators of training adaptation than supine measures.

Physical activity may contribute to brain health in multiple sclerosis: An MR volumetric and spectroscopy study.

BACKGROUND AND PURPOSE: Physical activity may represent a disease-modifying therapy in persons with multiple sclerosis (pwMS). To date, there is limited research regarding mechanisms based on brain imaging for understanding the beneficial effects of physical activity in pwMS. This study examined the relationship between physical activity levels and thalamic and hippocampal volumes and brain metabolism in pwMS. METHODS: The sample of 52 pwMS (37.3 ± 9.6 years of age; 35 females, 17 males) underwent a combination of volumetric magnetic resonance imaging and magnetic resonance spectroscopy. Current and lifetime physical activity were assessed using actigraphy and the adapted version of the Historical Activity Questionnaire, respectively. RESULTS: Positive associations were observed between both actigraphy and self-reported levels of moderate-to-vigorous physical activity (MVPA) and thalamic and hippocampal volumes. Regarding brain metabolism, actigraphy and self-reported levels of MVPA were positively associated with higher hippocampal and thalamic levels of N-acetylaspartate/creatine ratio (NAA/Cr: marker of neural integrity and cell energy state). CONCLUSIONS: This study provides novel evidence for a positive association between physical activity and thalamic and hippocampal volume and metabolism in pwMS. These findings support the hypothesis that physical activity, particularly MVPA, may serve as a disease-modifying treatment by improving brain health in pwMS.

Exercise training and cognitive performance in persons with multiple sclerosis: A systematic review and multilevel meta-analysis of clinical trials.

BACKGROUND: Cognitive impairment is common, debilitating, and poorly managed in persons with multiple sclerosis (pwMS). Exercise training might have positive effects on cognitive performance in pwMS, yet the overall magnitude, heterogeneity, and potential moderators remain unclear. OBJECTIVE: This three-level meta-analysis aims to identify the effects of exercise training and those of exercise modalities on global and domain-specific cognitive performance in pwMS. METHODS: MEDLINE, PsycInfo, SportDiscus, CENTRAL, and EMBASE were screened for randomized and non-randomized clinical trials from inception to 27 January 2020, yielding 3091 articles. Based on titles and abstracts, 75 articles remained in the selection process. After full-text evaluation, 13 studies were finally selected (PROSPERO pre-registered). RESULTS: The pooled effect of exercise training on the global cognitive performance was null (g = 0.04, 95% confidence interval (CI): -0.11 to 0.18) and no significant differences were displayed among domains. Heterogeneity within studies was null (I(2)2= 0.0%) and between studies was low (I(3)2= 25.1%). None of the moderators (exercise modalities, age, Expanded Disability Status Scale (EDSS), supervision, cognitive domains) reached significance. However, the exercise volume explained most of the overall heterogeneity (slope = 4.651 × 10-5, R(2)2 = 100%, R(3)2 = 52.34%). CONCLUSION: These results do not support the efficacy of exercise training on global or domain-specific cognitive performance in pwMS. Future studies are needed to determine whether higher training dose are beneficial.

The Changes of Heart miR-1 and miR-133 Expressions following Physiological Hypertrophy Due to Endurance Training.

OBJECTIVE: MicroRNAs (miRNAs) play a key role in the development of the heart. Recent studies have shown that miR- 1 and miR-133 are key regulators of cardiac hypertrophy. Therefore, we aimed to evaluate the effect of an endurance training (ET) program on the expressions of these miRNAs and their transcriptional network. MATERIALS AND METHODS: In this experimental study, cardiac hypertrophy was induced by 14 weeks of ET for 1 hour per day, 6 days per week at 75% VO2 max). The rats (221 ± 23 g) in the experimental (n=7) and control (n=7) groups were anesthetized to evaluate heart morphology changes by echocardiography. Next, we evaluated expressions of miR-1 and miR-133, and heart and neural crest derivatives express 2 (Hand2), Mef2c, histone deacetylase 4 (Hdac4) and serum response factor (Srf) gene expressions by real-time polymerase chain reaction (PCR). Finally, the collected data were evaluated by the independent t test to determine differences between the groups. RESULTS: The echocardiography result confirmed physiological hypertrophy in the experimental group that underwent ET as shown by the increased left ventricular weight/body surface area (LVW/BSA) (P=0.004), LVW/body weight (BW) (P=0.011), left ventricular diameter end-diastolic (LVDd) (P=0.003), and improvements in heart functional indexes such as fractional shortness (FS) (P=0.036) and stroke volume (SV) (P=0.002). There were significant increases in the expressions of miR-1 (P=0.001) and miR-133 (P=0.004). The expressions of Srf, Hdac4, and Hand2 genes significantly increased (P<0.001) in the experimental group Compared with the control group. The expression of Mef2c did not significantly change. CONCLUSION: The expressions of miR-1 and miR-133 and their target genes appeared to be involved in physiological hypertrophy induced by ET in these rats.

The effects of aerobic training before and after the induction of Alzheimer's disease on ABCA1 and APOE mRNA expression and the level of soluble Aß1-42 in the hippocampus of male Wistar rats.

OBJECTIVES: The purpose of this study was to investigate the effects of aerobic training before and after the induction of Alzheimer's disease on ABCA1 and APOE mRNA expression and the level of soluble Aß1-42 in the hippocampus of male Wistar rats. MATERIALS AND METHODS: Ninety six eight-week-old male Wistar rats were randomly divided into two groups: Training (n=48) and Rest (n=48). After four weeks, each group was randomly divided into two subgroups: intra-hippocampal injection of Aß1-42 (n=24) and DMSO (n=24). Then, each group was again randomly divided into two groups: Training (n=12) and Rest (n=12). After four weeks, each group was again randomly divided into two groups: Behavioral test (n=7) and sacrificed (n=5). RESULTS: The one-way ANOVA showed a significant increase in the mRNA expression of ABCA1 (P<0.05), a significant decrease in the level of soluble Aß1-42, and no significant difference in the expression of APOE mRNA (P>0.05) in the hippocampus as a result of training. The analysis of the Morris water maze data showed that intra-hippocampal injection of Aß1-42 impaired spatial learning and memory and exercise improved spatial learning (P<0.05) and memory (P<0.05). CONCLUSION: Therefore, aerobic training by a significant increase in the mRNA expression of ABCA1, which is the main factors of lipid metabolism in the brain and which is involved in the pathology of Alzheimer's disease, can be consistent with improving cognitive function as an effective way of preventing and improving the symptoms of Alzheimer's disease.

Effect of a Short-term Lifestyle Modification Program on Quality of Life, Anthropometric Characteristics and CD4+T Cell Count of HIV Infected Patients in Tehran/Iran: A Randomized Controlled Trial.

CONTEXT: Increasing physical activity and promoting healthy behaviors may play a key role in reducing the adverse effects of antiretroviral therapy and HIV. OBJECTIVE: This study investigated the effects of an 8-week lifestyle modification program (LMP) on quality of life, anthropometric characteristics and CD4+T cell count of people living with HIV (PLWH). METHODS: Thirty PLWH taking ART were randomly assigned to a lifestyle modification program (LMP) (n = 15) or standard care control (CON) group (n = 15). All volunteers underwent body composition, CD4+T cell count measurement and quality of life assessments at the beginning and end of a two-month experimental period. RESULTS: At follow-up, we observed a significant increase in CD4+T cell count (117.52 cells/mm3; 95% CI, 36.59-198.45) and all subscales and total quality of life score (Short-Form 36 (SF-36) in the LMP group. While we did not observe a significant change in body composition for the LMP group, we did observe a significant increase in body fat (1.75%; 95% CI, 0.15, 2.33) and a reduction in lean body mass (-1.26; 95% CI, -1.26, -2.39) for the CON group. CONCLUSION: A LMP can be safely used as an effective intervention for improving quality of life and immune competence of PLWH who lack time to participate in a structured exercise regimen. TRIAL REGISTRATION: IRCT 201604034076N18. Registered: 2016-05-05 .web address of TRIAL: en.search.irct.ir/trial/4262.

Effects of exercise training and supplementation with selenium nanoparticle on T-helper 1 and 2 and cytokine levels in tumor tissue of mice bearing the 4 T1 mammary carcinoma.

OBJECTIVES: Physical exercise decreases the incidence of breast cancer and also improves survival in breast cancer patients. However, the mechanistic basis of these protective effects of exercise is not well known. Changes in tumor cytokines, such as oncostatin-M (OSM), have been associated with modulation of antitumor immune responses in breast cancer. Exercise and antioxidants such as selenium affect both antitumor immune responses as well as tumor cytokine expression. Thus, the aim of this study was to determine the effects of aerobic exercise training (AET) and selenium nanoparticle (SeNP) administration on T-helper 1 and 2 and tumor tissue cytokines in mice bearing the 4 T1 mammary carcinoma. METHODS: We examined the effects of 6 wk of AET and SeNP administration (100 µg three times/wk) on tumor size, concentration of tumor necrosis factor (TNF)-α, interleukin (IL)-6, interferon (IFN)-γ, IL-4 and OSM in tumor tissue and INF-γ and IL-4 in splenocytes of 64 mice bearing the 4 T1 mammary carcinoma. RESULTS: AET increased OSM levels in tumor tissue. Moreover, AET increased levels of TNF-α in tumor tissue, whereas SeNP supplementation decreased IL-4 levels tumor tissue. Also, the combination of AET and SeNP administration decreased tumor volume and increased T-helper 1 cytokines in the splenocytes of tumor-bearing mice. CONCLUSION: These findings suggest that the combination of AET and SeNP supplementation effects antitumor immune responses in splenocytes, whereas AET induced antitumor cytokines, such as OSM and TNF-α in tumor tissue.

Treadmill Exercise Ameliorates Spatial Learning and Memory Deficits Through Improving the Clearance of Peripheral and Central Amyloid-Beta Levels.

Aggregated amyloid beta (Aß) peptides are believed to play a decisive role in the pathology of Alzheimer's disease (AD). Previous evidence suggested that exercise contributes to the improvement of cognitive decline and slows down pathogenesis of AD; however, the exact mechanisms for this have not been fully understood. Here, we evaluated the effect of a 4-week moderate treadmill exercise on spatial memory via central and peripheral Aß clearance mechanisms following developed AD-like neuropathology induced by intra-hippocampal Aß1-42 injection in male Wistar rats. We found Aß1-42-treated animals showed spatial learning and memory impairment which was accompanied by increased levels of amyloid plaque load and soluble Aß1-42 (sAß1-42), decreased mRNA and protein expression of neprilysin (NEP), insulin degrading enzyme (IDE) and low-density lipoprotein receptor-related protein-1 (LRP-1) in the hippocampus. Aß1-42-treated animals also exhibited a higher level of sAß1-42 and a lower level of soluble LRP-1 (sLRP-1) in plasma, as well as a decreased level of LRP-1 mRNA and protein content in the liver. However, exercise training improved the spatial learning and memory deficits, reduced both plaque load and sAß1-42 levels, and up-regulated expression of NEP, IDE, and LRP-1 in the hippocampus of Aß1-42-treated animals. Aß1-42-treated animals subjected to treadmill exercise also revealed decreased levels of sAß1-42 and increased levels of sLRP-1 in plasma, as well as increased levels of LRP-1 mRNA and protein in the liver. In conclusion, our findings suggest that exercise-induced improvement in both of central and peripheral Aß clearance are likely involved in ameliorating spatial learning and memory deficits in an animal model of AD. Future studies need to determine their relative contribution.

Swimming Training Attenuates Allodynia and Hyperalgesia Induced by Peripheral Nerve Injury in an Adult Male Rat Neuropathic Model: Effects on Irisin and GAD65.

Objective: The analgesic mechanism of long-lasting exercise on neuropathic pain is not well understood. This study explored the effects of swimming training on neuropathic pain and the expression of irisin, GAD65, and P2X3 after chronic constriction injury (CCI) of the sciatic nerve. Methods: Thirty-five male rats were randomly assigned to one of the following five groups: 1) no CCI or swimming (control); 2) swimming without CCI (SW); 3) swimming with CCI (CCISW); 4) CCI without swimming (CCI); and 5) sham CCI surgery (sham CCI). Behavioral responses to mechanical, cold, and heat stimuli were tested before and after CCI surgery, as well as each week throughout the four weeks of swimming training. The expression of irisin, GAD65, and P2X3 proteins in L4-L6 spinal cord segment, ipsilateral to the nerve injury, were evaluated by western blotting. Results: Mechanical hyperalgesia was alleviated between the second and fourth weeks of training in the CCISW group. In the tactile allodynia and heat hyperalgesia tests, withdrawal thresholds of the CCISW group were significantly higher than the CCI group at the third and fourth week of training (P < 0.05), while cold allodynia showed delayed improvement occurring by the fourth week of training. The expression of irisin was lower in the CCISW and SW groups compared with the CCI group at day 33 post-CCI surgery. Moreover, CCI surgery significantly decreased the protein expression of GAD65 in L4-L6 spinal cord segments (P = 0.018), whereas swimming training prevented the decline of GAD65 in the CCISW group. Conclusions: Our findings showed that four weeks of swimming training produce beneficial rehabilitative effects on neuropathic pain symptoms. The analgesic effect of swimming training is partially related to the increase of GAD65. The beneficial role of irisin in neuropathic pain will require further investigation.

Moderate treadmill exercise ameliorates amyloid-ß-induced learning and memory impairment, possibly via increasing AMPK activity and up-regulation of the PGC-1α/FNDC5/BDNF pathway.

Alzheimer's disease (AD) is a neurodegenerative disorder associated with loss of memory and cognitive abilities. Previous evidence suggested that exercise ameliorates learning and memory deficits by increasing brain derived neurotrophic factor (BDNF) and activating downstream pathways in AD animal models. However, upstream pathways related to increase BDNF induced by exercise in AD animal models are not well known. We investigated the effects of moderate treadmill exercise on Aß-induced learning and memory impairment as well as the upstream pathway responsible for increasing hippocampal BDNF in an animal model of AD. Animals were divided into five groups: Intact, Sham, Aß1-42, Sham-exercise (Sham-exe) and Aß1-42-exercise (Aß-exe). Aß was microinjected into the CA1 area of the hippocampus and then animals in the exercise groups were subjected to moderate treadmill exercise (for 4 weeks with 5 sessions per week) 7 days after microinjection. In the present study the Morris water maze (MWM) test was used to assess spatial learning and memory. Hippocampal mRNA levels of BDNF, peroxisome proliferator-activated receptor gamma co-activator 1 alpha (PGC-1α), fibronectin type III domain-containing 5 (FNDC5) as well as protein levels of AMPK-activated protein kinase (AMPK), PGC-1α, BDNF, phosphorylation of AMPK were measured. Our results showed that intra-hippocampal injection of Aß1-42 impaired spatial learning and memory which was accompanied by reduced AMPK activity (p-AMPK/total-AMPK ratio) and suppression of the PGC-1α/FNDC5/BDNF pathway in the hippocampus of rats. In contrast, moderate treadmill exercise ameliorated the Aß1-42-induced spatial learning and memory deficit, which was accompanied by restored AMPK activity and PGC-1α/FNDC5/BDNF levels. Our results suggest that the increased AMPK activity and up-regulation of the PGC-1α/FNDC5/BDNF pathway by exercise are likely involved in mediating the beneficial effects of exercise on Aß-induced learning and memory impairment.

"Women and active life": An extended TPB-based multimedia software to boost and sustain physical activity and fitness of Iranian women.

Inactivity is prevalent in women, although regular physical activity (PA) has significant health benefits. Health education interventions based on multimedia software and the extended theory of planned behavior (TPB) with planning may be efficacious in promoting PA. This randomized controlled trial, conducted in 2014, aimed to evaluate theory-based multimedia for increasing and maintaining PA and fitness of 130 military personnel's wives in Tehran, Iran. We randomly selected respondents by multistage cluster sampling. We designed a "Women and Active Life" self-taught DVD-Rom, based on the extended TPB model with action and coping planning. We analyzed theoretical constructs and health-related physical fitness at baseline and 3 and 6 months post-education. Administering educational software raised average developed TPB constructs, cardiorespiratory endurance, and muscular fitness (strength, endurance, and flexibility) in women in the intervention group, which was sustained at follow-up (p < .001). Also, mean body composition (body fat percentage, waist-hip ratio, and body mass index) was reduced with retained reduction at follow-up (p < .001), although no significant change was found in these variables in the control group (p > .05). Using a new communication technology in TPB-directed multimedia led to improved and maintained PA, aerobic and musculoskeletal fitness, and body composition of women.

Does Endurance Training Compensate for Neurotrophin Deficiency Following Diabetic Neuropathy?

BACKGROUND: A lack of neurotrophic support is believed to contribute to the development of diabetic neuropathy. On the other hand, neurotrophins have consistently been shown to increase in the central and peripheral nervous system following exercise, but the effects of exercise intervention on brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) in diabetic neuropathy are not understood. OBJECTIVES: This experimental study was designed and carried out at the Tarbiat Modares university (TMU) in Tehran, Iran, to investigate the hypothesis that increased activity as endurance training can help to increase the endogenous expression of neurotrophins in diabetic rats. METHODS: This was an experimental study with 2 × 2 factorial plans performed at TMU in Iran. Sampling was accidental and 28 adult male Wistar rats in the body mass range of 326.3 ± 8.4 g comprised the sample, with each rat randomly assigned to four groups: diabetic control (DC), diabetic training (DT), healthy control (HC), and healthy training (HT). To induce diabetic neuropathy, after 12 hours of food deprivation, an intraperitoneal injection of streptozotocin (STZ) solution (45 mg/Kg) method was used. Two weeks after STZ injection, the endurance training protocol was performed for 6 weeks; 24 hours after the last training session, the rats were sacrificed. Real-time PCR was used for BDNF and NGF expression. RESULTS: The data indicate that diabetes decreases BDNF and NGF expression in sensory (92%, P = 0.01; 90%, P = 0.038, respectively) and motor (93%, P = 0.05; 60%, P = 0.029, respectively) roots. However, NGF mRNA levels in the DT group were significantly higher than in the HC group ((7.1-fold), P = 0.01; (2.2-fold), P = 0.001, respectively, for sensory and motor roots), but this was not shown for BDNF. In addition, endurance training can increase NGF expression in healthy rats ((7.4-fold), P = 0.01; (3.8-fold), P = 0.001, respectively, for sensory and motor roots). CONCLUSIONS: This study shows that BDNF and NGF expression decreases in diabetic neuropathy. However, this decrease can be reversed through endurance training. These results also indicate that endurance training may have a potential role in compensating for neurotrophin deficiency following diabetic neuropathy.

The effect of endurance training and downhill running on the expression of IL-1ß, IL-6, and TNF-α and HSP72 in rat skeletal muscle.

This study investigated changes in the myokines IL-1ß, IL-6, and TNF-α, as well as HSP72, after endurance training and after a session of downhill running. Twenty-eight rats were allocated to four different groups: 1. Eight weeks of endurance training at 65-70% VO2max (Trained); 2. Endurance training and a single session of downhill running on a 16° slope (Trained plus downhill); 3. A single session of downhill running (Sedentary plus downhill); and 4. Sedentary (Control, no exercise). Soleus and extensor digitorum longus (EDL) muscles were harvested 48h after training and/or a single session of downhill running and protein levels of IL-1ß, IL-6, TNF-α, and HSP72 were measured and compared to the levels in the control animals. Creatine kinase (CK) was measured in plasma. Endurance training augmented intramuscular levels of HSP72 and IL-6 in both soleus and EDL muscles (p<0.05). Endurance training elevated IL-1ß and decreased TNF-α significantly only in EDL (P<0.05). IL-6 increased in both sedentary and trained rats after downhill running (P<0.05), while HSP72 increased only in the previously sedentary rats. CK was lower in trained than sedentary rats after downhill running. In conclusion, endurance training for 8weeks elevated muscular HSP72 protein levels, which might have preconditioned the muscles for a single session of downhill running, as indicated by the CK and HSP72 responses. Interestingly, IL-6 was augmented by endurance training and further increased by downhill running. IL-1ß, along with IL-6, was increased by endurance training, and these myokines thus appear to be differently regulated than TNF-α.

Treadmill training modifies KIF5B motor protein in the STZ-induced diabetic rat spinal cord and sciatic nerve.

BACKGROUND: Previous research has demonstrated diabetic-induced axonal transport deficits. However, the mechanism of axonal transport impairment induced by diabetes is poorly understood. Kinesin motor proteins have been shown to transport various cargos along highly polarized neurons. In the present study, we investigated the effect of regular treadmill exercise on KIF5B and Sunday Driver (SYD) mRNA levels in sensory and motor parts of spinal cord and KIF5B content in sciatic nerves of streptozotocin (STZ)-induced diabetic rats.  METHODS: Forty male Wistar rats were divided into four groups: (1) diabetic trained (DT: n = 10); (2) Non-trained diabetic (NTD: n = 10); (3) normal control (NC: n = 10), and (4) normal trained (NT: n = 10). Two weeks after STZ injection (45 mg/kg, i.p.), the rats were subjected to treadmill exercise for 5 days a week over 6 weeks. We determined mRNA levels and protein content by Real time- PCR and ELISA.  RESULTS: Exercise training decreased blood glucose levels in the DT rats. Diabetes increased the KIF5B and SYD mRNA in both sensory and motor parts and KIF5B content in sciatic nerves in the NTD. Moreover, exercise training modulated the KIF5B and SYD mRNA and KIF5B content to normal levels in the DT. Exercise training in NT rats increased KIF5B and SYD mRNA in sensory and motor parts and KIF5B content in sciatic nerves.  CONCLUSIONS: Our results suggest that diabetes seems to change spinal cord KIF5B and SYD mRNA and sciatic nerves KIF5B content and exercise training modifies it, which may be attributable to the training-induced decreased hyperglycemia.

Time course of IL-15 expression after acute resistance exercise in trained rats: effect of diabetes and skeletal muscle phenotype.

Type 1 diabetes is associated with skeletal muscle atrophy. Skeletal muscle is an endocrine organ producing myokines such as interleukin-15 (IL-15) and interleukin-6 (IL-6) in response to contraction. These factors may mediate the effects of exercise on skeletal muscle metabolism and anabolic pathways. Lack of correlation between muscle IL-15 mRNA and protein levels after exercise training has been observed, while regulatory effects of IL-6 on IL-15 expression have also been suggested. This study determined post-exercise changes in muscle IL-15 and IL-6 mRNA expression and IL-15 protein levels in healthy and streptozotocin-induced diabetic rats in both the fast flexor hallucis longus (FHL) and slow soleus muscles. Resistance training preserved FHL muscle weight in diabetic rats and increased IL-15 protein levels in both the soleus and FHL muscles. However, the temporal pattern of this response was distinct in normal and diabetic rats. Moreover, discordance between post-exercise muscle IL-15 mRNA and protein expression was observed in our study, and diabetes suppressed post-exercise increases in FHL muscle IL-6 mRNA expression. Our study indicates that training, skeletal muscle phenotype, and metabolic status all influence the temporal pattern of post-exercise changes in IL-15 expression. Muscle IL-15 protein levels increase following training, suggesting this may be an adaptation contributing to increased capacity for secretion of this myokine that is not depressed by the diabetic state.

The effect of high-fat diet and streptozotocin-induced diabetes and endurance training on plasma levels of calcitonin gene-related peptide and lactate in rats.

OBJECTIVE: The aim of this study was to investigate the effect of type 2 diabetes induced by high-fat diet and streptozotocin, and the effect of endurance training on basal circulating levels of calcitonin gene-related peptide (CGRP) and lactate. METHODS: Male Wistar rats were randomly divided into 4 groups: 1) control (n=8); 2) trained (n=8); 3) diabetic (n=8) and 4) trained diabetic (n=8). At the age of 7 weeks, diabetes was induced by feeding the animals a high-fat diet and injecting them with a low dose of streptozotocin (35 mg/kg). The animals at 10 weeks of age underwent an endurance training protocol on a treadmill for 7 weeks. Plasma lactate concentrations were measured by a lactate assay kit, and an enzyme immunoassay kit was used to measure CGRP. RESULTS: The diabetic rats showed significant increases in plasma CGRP (3.0±1 ng/mL vs. 0.5±0.3 ng/mL, p<0.001) and plasma lactate levels (3.6±0.5 mmol/L vs. 1.3±0.5 mmol/L, p<0.001). Further, significant decrease in basal plasma lactate (2.6±0.5 mmol/L vs. 3.6±0.5 mmol/L, p<0.025) but not plasma CGRP levels (2.5±1.2 ng/mL vs. 3.0±1.3 ng/mL) were found in the diabetic subjects after the endurance training. CONCLUSIONS: The results showed that endurance training could modify the basal circulating levels of lactate but not CGRP, which were elevated in this model of type 2 diabetic rats, indicating the lack of correspondence between the endurance training-induced changes of lactate and CGRP in this model of diabetes.