Effect of acupuncture pretreatment on inflammatory response of exercise-induced skeletal muscle damage in rats based on TLR9/MyD88/NF-κB signaling pathway. / 基于TLR9/MyD88/NF­κBä¿¡å·é€šè·¯æŽ¢è®¨é’ˆåˆºé¢„å¤„ç†å¯¹è¿åŠ¨æ€§éª¨éª¼è‚ŒæŸä¼¤å¤§é¼ ç‚Žæ€§ååº”çš„å½±å“.

OBJECTIVES: To observe the effects of acupuncture pretreatment on toll-like receptor 9/myeloid differentiation factor 88/nuclear factor-κB (TLR9/MyD88/NF-κB) signaling pathway and inflammatory response in the rats with exercise-induced skeletal muscle damage (EIMD) and explore the underlying mechanism of this pretreatment for EIMD. METHODS: A total of 88 male SD rats were randomly divided into a blank group (8 rats), a model group (40 rats) and an acupuncture pretreatment group (40 rats). In the model group and the acupuncture pretreatment group, 5 subgroups were randomized according to the sampling time of 0, 12, 24, 48 and 72 h of modeling, with 8 rats in each one, respectively. Before modeling, in the acupuncture pretreatment group, acupuncture was delivered at bilateral "Zusanli" (ST 36) and "Guanyuan" (CV 4) for 20 min, once daily for consecutive 7 days. By one-time intermittent downhill centrifugal exercise on animal experimental treadmill, EIMD model was established in the model group and the acupuncture pretreatment group. The ultrastructure of gastrocnemius muscle was observed under transmission electron microscope. The levels of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in the serum were detected by ELISA. The protein and mRNA expression of TLR9, MyD88 and NF-κB p65 in the gastrocnemius tissue of rats was detected by the Western blot and real-time PCR, respectively. RESULTS: Compared with the blank group, the gastrocnemius ultrastructure in the model group showed the damage of different degrees, with myofilaments disarranged and twisted, mitochondria obviously swollen and mitochondrial crista partially defected. Compared with the model group, the injury was mild, most of muscle fibers were arranged neatly and the number of mitochondria increased remarkably in the acupuncture pretreatment group. Compared with the blank group, in the model group, the serum IL-6 levels increased at 0, 12, 24 and 48 h after modeling in the rats (P<0.01), and TNF-α levels were elevated at each time point after modeling (P<0.05, P<0.01). In the acupuncture pretreatment group, the serum IL-6 levels were reduced at 12, 24 and 48 h after modeling (P<0.01, P<0.05), and the TNF-α levels decreased at 24, 48 and 72 h after modeling (P<0.01) when compared with those in the model group at the same time points separately. The serum IL-6 and TNF-α levels ascended and then tended to decline in the model group and the acupuncture pretreatment group. Compared with the blank group, the protein and mRNA expression of TLR9 and NF-κB p65 in the gastrocnemius tissue increased at 12, 24, 48 and 72 h after modeling (P<0.01, P<0.05), and the protein and mRNA expression levels of MyD88 in the gastrocnemius tissue at each time point after modeling were elevated (P<0.05, P<0.01) in the model group. When compared with the model group at the same time points, in the acupuncture pretreatment group, the protein expression of TLR9 in the gastrocnemius tissue decreased at 12, 24, 48 and 72 h after modeling (P<0.05, P<0.01), and the mRNA expression of TLR9 was declined at 24, 48 and 72 h after modeling (P<0.01, P<0.05); the protein and mRNA expression of MyD88 in the gastrocnemius decreased at 24, 48 and 72 h after modeling (P<0.01, P<0.05), and that of NF-κB p65 was reduced at 24 h and 48 h after modeling (P<0.01). The protein and mRNA expression of TLR9, MyD88 and NF-κB p65 in the gastrocnemius tissue showed a trend of decrease after increase in the model group and the acupuncture pretreatment group. CONCLUSIONS: Acupuncture pretreatment can alleviate exercise-induced skeletal muscle damage, which may be related to modulating the expression of TLR9/MyD88/NF-κB signaling pathway to inhibit the inflammatory response.

Exercise Causes Arrhythmogenic Remodeling of Intracellular Calcium Dynamics in Plakophilin-2-Deficient Hearts.

BACKGROUND: Exercise training, and catecholaminergic stimulation, increase the incidence of arrhythmic events in patients affected with arrhythmogenic right ventricular cardiomyopathy correlated with plakophilin-2 (PKP2) mutations. Separate data show that reduced abundance of PKP2 leads to dysregulation of intracellular Ca2+ (Ca2+i) homeostasis. Here, we study the relation between excercise, catecholaminergic stimulation, Ca2+i homeostasis, and arrhythmogenesis in PKP2-deficient murine hearts. METHODS: Experiments were performed in myocytes from a cardiomyocyte-specific, tamoxifen-activated, PKP2 knockout murine line (PKP2cKO). For training, mice underwent 75 minutes of treadmill running once per day, 5 days each week for 6 weeks. We used multiple approaches including imaging, high-resolution mass spectrometry, electrocardiography, and pharmacological challenges to study the functional properties of cells/hearts in vitro and in vivo. RESULTS: In myocytes from PKP2cKO animals, training increased sarcoplasmic reticulum Ca2+ load, increased the frequency and amplitude of spontaneous ryanodine receptor (ryanodine receptor 2)-mediated Ca2+ release events (sparks), and changed the time course of sarcomeric shortening. Phosphoproteomics analysis revealed that training led to hyperphosphorylation of phospholamban in residues 16 and 17, suggesting a catecholaminergic component. Isoproterenol-induced increase in Ca2+i transient amplitude showed a differential response to ß-adrenergic blockade that depended on the purported ability of the blockers to reach intracellular receptors. Additional experiments showed significant reduction of isoproterenol-induced Ca2+i sparks and ventricular arrhythmias in PKP2cKO hearts exposed to an experimental blocker of ryanodine receptor 2 channels. CONCLUSIONS: Exercise disproportionately affects Ca2+i homeostasis in PKP2-deficient hearts in a manner facilitated by stimulation of intracellular ß-adrenergic receptors and hyperphosphorylation of phospholamban. These cellular changes create a proarrhythmogenic state that can be mitigated by ryanodine receptor 2 blockade. Our data unveil an arrhythmogenic mechanism for exercise-induced or catecholaminergic life-threatening arrhythmias in the setting of PKP2 deficit. We suggest that membrane-permeable ß-blockers are potentially more efficient for patients with arrhythmogenic right ventricular cardiomyopathy, highlight the potential for ryanodine receptor 2 channel blockers as treatment for the control of heart rhythm in the population at risk, and propose that PKP2-dependent and phospholamban-dependent arrhythmogenic right ventricular cardiomyopathy-related arrhythmias have a common mechanism.

Effect of one-time high load exercise on skeletal muscle injury in rats of different genders: oxidative stress and mitochondrial responses

Purpose: To evaluate the impact of one-time high load exercise on skeletal muscle injury and analysis its mechanism in different genders. Methods: Twenty-four male and 24 female rats were divided randomly into four groups respectively: control, 0 h, 6 h, and 24 h after exercise. The activities of creatine kinase (CK), lactate dehydrogenase (LDH), and myohemoglobin (MYO) in serum, the expression level of oxidative stress markers, mitochondrial respiratory chain complex enzyme, and the apoptosis related protein in quadriceps were detected. Results: The results showed that the activities of CK, LDH and MYO in serum increased immediately after exercise and restored faster in female rats. More obvious structural disorder and apoptosis in male rats were showed. Malondialdehyde (MDA) and superoxide dismutase (SOD) were increased while catalase (CAT) and glutathione (GSH) were decreased in male rats. SOD, CAT and GSH were increased in female rats. Mitochondrial complex enzyme activity was decreased in males and increased in females. Conclusions: The skeletal muscle injury in both genders of rat could be induced by one-time high load exercise due to the mitochondrial respiratory enzyme dysfunction and oxidative stress, which was relatively mild and recovered quicker in female rats.

Effect of intrabronchial platelet rich plasma on the exercise-induced pulmonary hemorrhage endoscopic score in thoroughbred racehorses using furosemide: a preliminary study / [Efeito da instilação intrabronquial de plasma rico em plaquetas no escore endoscópico da hemorragia pulmonar induzida por exercício em cavalos Puro-Sangue Inglês de corrida e usuários de furosemida: um estudo preliminar]

The high prevalence of exercise-induced pulmonary hemorrhage (EIPH) in athletic horses constitutes to be a challenge to the racing industry and a source of major concern to animal welfare. Both experimental and clinical evidence indicate that the use of autologous platelet-rich plasma (PRP) is a promising effector of repair in a variety of pulmonary conditions. The present study evaluated the effect of intrabronchial instillation of PRP on EIPH endoscopic scores from 37 Thoroughbred racehorses. Inclusion criteria were for animals to be EIPH-positive in, at least, two consecutive post-exercise endoscopic exams and to receive 250mg of furosemide IV four hours before racing. Animals were randomly assigned into 3 groups: placebo, control, and PRP instillation. All 37 Thoroughbred racehorses included had EIPH endoscopic scores pre- and post- treatment compared by statistical analysis. The bleeding score from the group receiving PRP was significantly lower than in the control and placebo groups. No adverse effects were observed in any animal during or after the experiment. It was possible to conclude that the intrabronchial instillation of autologous PRP was effective in reducing EIPH scores in racehorses receiving furosemide and that this bioproduct can be considered as a promising coadjuvant in controlling EIPH in athletic horses.(AU)

A alta prevalência de hemorragia pulmonar induzida por exercício (HPIE) em cavalos atletas é um desafio de longa data para a indústria de corridas, além de figurar como grande preocupação sobre o bem-estar animal. As evidências experimentais e clínicas indicam que o uso do plasma rico em plaquetas (PRP) de fonte autógena é promissor na terapêutica de diversas lesões pulmonares. O presente estudo objetivou avaliar as mudanças após corrida no escore endoscópico de HPIE de 37 cavalos Puro-Sangue Inglês que receberam instilação intrabronquial de PRP autólogo. Os animais selecionados eram HPIE-positivos em, ao menos, dois exames endoscópicos consecutivos e recebiam 250mg de furosemida IV administrado quatro horas antes de cada corrida. Na comparação dos escores endoscópicos pré e pós-tratamento, verificou-se que o escore de HPIE do grupo tratado com PRP foi significantemente menor que o dos grupos controle e placebo. Nenhum efeito adverso foi observado nos animais durante ou após o experimento. Concluiu-se que a instilação intrabronquial de PRP autólogo foi efetiva na redução do escore de HPIE de cavalos de corrida usuários de furosemida e que este bioproduto pode ser considerado uma alternativa promissora no controle de HPIE em cavalos atletas.(AU)

MiR-30b-5p Influences Chronic Exercise Arthritic Injury by Targeting Hoxa1.

We identified the role of miR-30b-5p in chronic exercise arthritic injury. Rats with chronic exercise arthritic injury received treatment with miR-30b-5p antagomiR. H&E and Safranin O-fast green staining were performed. The levels of tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß) were detected. The binding relationship between homeobox A1 (Hoxa1) and miR-30b-5p was revealed. After manipulating the expressions of miR-30b-5p and/or Hoxa1 in chondrocytes, the viability, apoptosis and migration of chondrocytes were assessed. The levels of molecules were determined by qRT-PCR or Western blot. MiR-30b-5p antagomiR ameliorated articular cartilage lesion and destruction, reduced Mankin's score and the levels of TNF-α, IL-1ß, miR-30b-5p, matrix metallopeptidase 13 (MMP-13), and cleaved caspase-3, and increased relative thickness and the levels of Hoxa1, Aggrecan and type II collagen (COLII) in model rats. MiR-30b-5p up-regulation decreased Hoxa1 level, viability, migration and induced apoptosis, whereas miR-30b-5p down-regulation produced the opposite effects. MiR-30b-5p up-regulation increased the levels of MMP-13 and cleaved caspase-3, but decreased those of Aggrecan and COLII in chondrocytes. However, the action of miR-30b-5p up-regulation on chondrocytes was reversed by Hoxa1 overexpression. In conclusion, miR-30b-5p is involved in cartilage degradation in rats with chronic exercise arthritic injury and regulates chondrocyte apoptosis and migration by targeting Hoxa1.

Polymethoxyflavones in orange peel extract prevent skeletal muscle damage induced by eccentric exercise in rats.

Polymethoxyflavones (PMFs) contained in the peel of citrus fruits have anti-inflammatory, anticancer, and antidepressant effects. However, their effects on skeletal muscle are unknown. We investigated whether PMFs could prevent skeletal muscle damage induced by eccentric exercise in rats. Downhill running for 90 min increased the levels of the inflammatory cytokines, monocyte chemotactic protein-1 (MCP-1), and interleukin-1ß (IL-1ß) in skeletal muscles, especially in vastus lateralis, and the plasma creatine kinase levels. These increases were attenuated by a single oral administration of orange peel extract (OPE) 30 min before downhill running. A mixture of nobiletin, sinensetin, 3,5,6,7,8,3',4'-heptamethoxyflavone, and tangeretin, which are the major PMFs of OPE, also showed similar effects on muscle damage. These results suggest that OPE has a protective effect against eccentric exercise-induced skeletal muscle damage, and that the effects may be attributed to the 4 major PMFs.

Moderate and intensive mechanical loading differentially modulate the phenotype of tendon stem/progenitor cells in vivo.

To examine the differential mechanobiological responses of specific resident tendon cells, we developed an in vivo model of whole-body irradiation followed by injection of either tendon stem/progenitor cells (TSCs) expressing green fluorescent protein (GFP-TSCs) or mature tenocytes expressing GFP (GFP-TNCs) into the patellar tendons of wild type C57 mice. Injected mice were subjected to short term (3 weeks) treadmill running, specifically moderate treadmill running (MTR) and intensive treadmill running (ITR). In MTR mice, both GFP-TSC and GFP-TNC injected tendons maintained normal cell morphology with elevated expression of tendon related markers collagen I and tenomodulin. In ITR mice injected with GFP-TNCs, cells also maintained an elongated shape similar to the shape found in normal/untreated control mice, as well as elevated expression of tendon related markers. However, ITR mice injected with GFP-TSCs showed abnormal changes, such as cell morphology transitioning to a round shape, elevated chondrogenic differentiation, and increased gene expression of non-tenocyte related genes LPL, Runx-2, and SOX-9. Increased gene expression data was supported by immunostaining showing elevated expression of SOX-9, Runx-2, and PPARγ. This study provides evidence that while MTR maintains tendon homeostasis by promoting the differentiation of TSCs into TNCs, ITR causes the onset of tendinopathy development by inducing non-tenocyte differentiation of TSCs, which may eventually lead to the formation of non-tendinous tissues in tendon tissue after long term mechanical overloading conditions on the tendon.

Semaglutide attenuates excessive exercise-induced myocardial injury through inhibiting oxidative stress and inflammation in rats.

AIMS: To investigate the protective effects and mechanism of semaglutide on exercise-induced myocardial injury. MAIN METHODS: Effects of semaglutide on lipopolysaccharide (LPS)-induced oxidative stress injuries and inflammatory response were assessed in H9c2 cell via MTT assay and Western blot. Quiet control group, over training group and three doses of semaglutide treated overtraining groups were subjected to the swimming training with increasing load for consecutive 10 weeks. Immediately after the last training, the body weight, myocardial morphological changes, injury markers and inflammatory response related proteins of the model rats were analyzed. KEY FINDINGS: Semaglutide at three concentrations in LPS treated H9c2 cells significantly increased the survival rate and inhibited the apoptosis of cardiomyocytes. Moreover, semaglutide activated AMPK pathway, improve autophagy and inhibited reactive oxygen species production in LPS treated H9C2 cells. In vivo results further revealed that chronic treatment of semaglutide induced significant increase in myocardial injury markers. The pathological histology analysis results showed that semaglutide ameliorated myocardial morphological changes, reduced area of lipid accumulation and significantly decreased the expression levels of NF-κB, TNF-α and IL-1ß. SIGNIFICANCE: Semaglutide exert the protective effects on exercise-induced cardiomyopathy by activating AMPK pathway, increasing autophagy, reducing the production of ROS and inflammation-related proteins.

Forced running exercise mitigates radiation-induced cognitive deficits via regulated DNA hydroxymethylation.

Aim: Roles of forced running exercise (FE) in remediation of neurogenesis inhibition and radiation-induced cognitive dysfunction were investigated in a whole-brain irradiation mice model via the regulation of DNA 5-hydroxymethylation modification (5 hmC) and its catalytic enzymes ten-eleven translocation (Tet) proteins. Materials & methods: Hippocampal neurogenesis and cognitive function, DNA 5 hmC level and Tet expression were determined in mice. Results: The expression of DNA 5 hmC and Tet2, brain-derived neurotrophic factor significantly decreased in hippocampus postradiation. FE mitigated radiation-induced neurogenesis deficits and cognitive dysfunction. Furthermore, FE increased 5 hmC and brain-derived neurotrophic factor expression. SC1, a Tet inhibitor, reversed partly such changes. Conclusion: Tet-mediated 5 hmC modification represents a kind of diagnostic biomarkers of radiation-induced cognitive dysfunction. Targeting Tet-related epigenetic modification may be a novel therapeutic strategy for radiation-induced brain injury.

Inhaled molecular hydrogen attenuates intense acute exercise-induced hippocampal inflammation in sedentary rats.

Physical exercise-induced inflammation may be beneficial when exercise is regular but it may be harmful when exercise is intense and performed by unaccustomed individuals/rats. Molecular hydrogen (H2) has recently emerged as a powerful anti-inflammatory, antioxidant and anti-apoptotic molecule in a number of pathological conditions, but little is known about its putative role under physiological conditions such as physical exercise. Therefore, we tested the hypothesis that H2 decreases intense acute exercise-induced inflammation in the hippocampus, since it is a brain region particularly susceptible to inflammation. Moreover, we also assessed hippocampus oxidative status. Rats ran on a sealed treadmill inhaling either the H2 (2% H2, 21% O2, balanced with N2) or the control gas (0% H2, 21% O2, balanced with N2) and hippocampal samples were collected immediately or 3 h after exercise. We measured hippocampal levels of cytokines [tumor necrosis factor-α (TNF-α), interleukin (IL)-1ß, IL-6 and IL-10] and oxidative markers [superoxide dismutase (SOD), thiobarbituric acid reactive species (TBARS) and nitrite/nitrate (NOx)]. Exercise increased TNF-α, IL-6 and IL-10 immediately after the session, whereas no change in IL-1ß levels was observed. Conversely, exercise did not cause any change in SOD activity, TBARS and NOx levels. H2 inhibited the exercise-induced surges in TNF-α and IL-6, and potentiated the IL-10 surge, immediately after the exercise. Moreover, no change in IL1-ß levels of rats inhaling H2 was observed. Regarding the oxidative stress markers, H2 failed to cause any change in SOD activity, TBARS and NOx levels. No significant change was observed in any of the assessed parameters 3 h after the exercise bout. These data are consistent with the notion that H2 acts as a powerful anti-inflammatory agent not only down-modulating pro-inflammatory cytokines (TNF-α and IL-6) but also upregulating an anti-inflammatory cytokine (IL-10) production without affecting the local oxidative stress status. These data indicate that H2 effectively decreases exercise-induced inflammation in the hippocampus, despite the fact that this region is particularly prone to inflammatory insults.

Relationship between tracheobronchoscopic score and bronchoalveolar lavage red blood cell numbers in the diagnosis of exercise-induced pulmonary hemorrhage in horses.

BACKGROUND: Exercise-induced pulmonary hemorrhage (EIPH) is diagnosed and its severity assessed by post-exercise tracheobronchoscopy, and enumeration of bronchoalveolar lavage fluid red blood cells (BALFRBC). Minimal information is available regarding the relationship of tracheobronchoscopy score to BALFRBC number. OBJECTIVE: Evaluate the relationship between BALFRBC number and tracheobronchoscopy scores and determine their diagnostic sensitivities. ANIMALS: Nine sedentary horses, 21 fit Thoroughbreds, 129 Barrel Racers. METHODS: Normal BALFRBC number and the effect of bronchoalveolar lavage (BAL) on it were evaluated by performing 2 BALs 24 hours apart in sedentary horses. Tracheobronchoscopy followed by BAL was performed 247 times on 150 horses after treadmill, racetrack, or barrel racing exercise. Lastly, a BALFRBC diagnostic threshold number that optimized the geometric mean of the sensitivity and precision (F1-score) was determined using Bayesian analysis. RESULTS: No increase in BALFRBC occurred after the second BAL (mean ± SD, 304 ± 173/µL). Tracheobronchoscopy scores ranged from 0 (n = 112) to 4 (n = 4) and BALFRBC ranged from 102 to 4605268/µL. Spearman correlation between tracheobronchoscopy score and BALFRBC was weak (P < .001; rs = 0.42) with large ranges of BALFRBC associated with each tracheobronchoscopy score. The highest F1-score occurred for a BALFRBC threshold number = 992/µL. Seventy-five tracheobronchoscopy scores equaled 0 although BALFRBC number was ≥992/µL. Sensitivity of tracheobronchoscopy for diagnosing EIPH was poor (0.59; 95% confidence intervals [CI], 0.49-0.68), compared to BALFRBC number ≥992/µL (0.93; 95% CI, 0.88-0.96). CONCLUSIONS AND CLINICAL IMPORTANCE: False negatives are common with tracheobronchoscopy. Follow-up determination of BALFRBC may be indicated for tracheobronchoscopy scores = 0 before EIPH can be ruled out.

Effect of Changing Diet on Gastric Ulceration in Exercising Horses and Ponies After Cessation of Omeprazole Treatment.

Diet is an accepted risk factor for equine squamous gastric disease (ESGD), but there is little published evidence for the benefit of dietary change (DC). This study evaluated the effect of DC with or without initial omeprazole medication. Twelve pairs of exercising horses with ESGD Grade 2/4 (EM) and 17 pairs with ESGD Grade ≥3/4 (ES), were monitored. Paired horses had similar management, feeding times, workloads, and initially feed or forage. One of each pair was randomly assigned, postgastroscopy (Scope1), to a specified restricted starch ration; the other remained on their original diet. Omeprazole (4 mg/kg per os SID) was given to all ES pairs for 4 weeks. Gastroscopies were scored, without dietary knowledge, after 4 and 10 weeks (Scopes 2 and 3). Workloads remained similar throughout. McNemar's tests identified any changes in ESGD grade. Within the EM group, DC had no additional effect. For the ES group remaining on their original diet, there was significant improvement in ESGD grade from Scopes 1 to 2 (P < .001) but a worsening between Scopes 2 and 3 (P = .005), with Scope 3 being no different from Scope 1 (P = .08) reflecting no apparent long-term medication benefit. For the DC group, there was significant improvement in ESGD grade from Scopes 1 to 2 (P < .001) and between Scopes 1 and 3 (P = .003); In addition, there was no significant difference between Scopes 2 and 3 (P = .32). Although limited by the small number of pairs evaluated, this study provides evidence that appropriate DCs can be a beneficial management strategy for ESGD.

Anti-Osteoporotic Effect of Soy Isoflavones Intake on Low Bone Mineral Density Caused by Voluntary Exercise and Food Restriction in Mature Female Rats.

Female athlete triad (FAT) is an interrelationship between menstrual dysfunction, low energy availability with or without eating disorder, and decreased bone mineral density (BMD) in female athletes. The purpose of this study was to investigate whether isoflavone intake can prevent bone loss caused by voluntary wheel running under energy-restricted condition. We used a female rat model of osteoporosis for female athletes established previously. Fourteen female Sprague-Dawley rats (8-wk old) were fed ad libitum and had free access to wheels throughout the study. At 18 wk of age, the rats were divided randomly into the following groups: 1) running control (RC), 2) running energy restriction (RR), and 3) running energy restriction and isoflavone-fed (RR+Iso) groups. The RR group was 30% dietary restricted. The RR+Iso group was 30% dietary restricted and fed the diet containing 0.5% isoflavone powder (Fujiflavone P40). The experimental period lasted 31 wk. At the end of this experiment, BMD of the proximal femur in the RR group was significantly lower than that in the RC group. However, the BMD in the RR+Iso group was not significantly different from that in the RC group. Moreover, the plasma estradiol (E2) level in the RR and RR+Iso groups was significantly lower than that in the RC group. These findings suggest that isoflavone intake inhibited bone loss when the E2 level was low in female mature rat model. Our findings may reveal the possible novel role of isoflavone in osteoporosis among female athletes.

Potential inhibitory effect of swimming exercise on the Kisspeptin-GnRH signaling pathway in male rats.

Aerobic exercises are considered as an effective method of improving several undesirable health outcomes; however, their implications in the male reproductive axis have remained controversial. The present study evaluated the impact of physical exercise on the male reproductive system in rats and investigated the potential central and peripheral mechanisms involved in it. Twenty male Sprague-Dawley rats were randomly divided into control and exercise groups, with 10 rats per group. The rats were subjected to a swimming exercise for 60 min/day for five days a week and the protocol was followed for six constitutive weeks. We found that the swimming exercise significantly decreased the testicular weight and the testicular somatic index. Furthermore, there was a marked reduction in several sperm characteristics, including sperm count, motility, morphology, and viability in the exercised rats. The serum levels of reproductive hormones, i.e., testosterone (T), luteinizing hormone (LH), and follicle stimulating hormone (FSH) were significantly decreased. A histological examination of testes and epididymis revealed defective spermatogenesis. Molecular analysis revealed the downregulation of the expression of mRNAs of the hypothalamic kisspeptin (Kiss1), Kiss1 receptor (Kiss1r), gonadotropin-releasing hormone (GnRH1), GnRH1 receptor (GnRHr), and testicular Kiss1r along with an upregulation in the gene expression of GnRHr in the pituitary. We also observed a significant reduction in the activity and the expression of mRNAs of testicular superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) and a marked elevation in the levelsof malondialdehyde (MDA). These findings implied that chronic swimming exercise suppressed the Kisspeptin-GnRH signaling pathway, consequently reducing the production of male reproductive hormones. A simultaneous increase in the oxidative stress could contribute to exercise-induced inhibition of male reproductive functions. To conclude, an appropriate training program is important to maximize the benefits and minimize the side effects of physical exercises on the male reproductive system.

Exercise-induced pulmonary haemorrhage in Thoroughbred racehorses: a longitudinal study.

BACKGROUND: Exercise-induced pulmonary haemorrhage (EIPH) is considered a progressive disease based on histopathology, but it is unknown if tracheobronchoscopic EIPH severity worsens over time. OBJECTIVES: The aim of this study was to examine tracheobronchoscopic EIPH changes over time in a population of Thoroughbred racehorses. A secondary aim was to identify factors that affect changes in tracheobronchoscopic EIPH severity between observations. STUDY DESIGN: Prospective, longitudinal, observational cross-sectional study. METHODS: Thoroughbred racehorses were examined with tracheobronchoscopy no earlier than 30 min after racing. Examinations were recorded and graded blindly by experienced veterinarians using a 0-4 scale. Horses with 2 or more observations were included in the analysis. The association between the previous and current EIPH score was investigated using a linear mixed effect model. Factors associated with transitioning from a lower to a high EIPH grade and vice versa were examined using multiple ordinal regression. A semi-parametric regression model was used to examine progression using the number of career starts as a marker for time. Models were adjusted for potential confounding variables. RESULTS: There were 2974 tracheobronchoscopic examinations performed on 747 horses. Blood was detected in over half of all examinations (55.6%). The population prevalence of EIPH increased as the number of examinations for each horse increased. The preceding EIPH score was significantly associated with the current EIPH score. Significant variables associated with moving between EIPH grades were the number of days since last racing, ambient temperature and weight carried. Tracheobronchoscopic EIPH is mildly progressive over the first thirty career starts. MAIN LIMITATIONS: Enrolment was voluntary. Horses were not followed for their entire career. CONCLUSION: Limiting the number of days in the current racing preparation and spacing races for horses with moderate to severe EIPH may be beneficial for reducing tracheobronchoscopic EIPH severity. The association between ambient temperature and EIPH warrants further investigation.

[Regulatory effects of curcumin on spleen apoptosis in overtraining rats and its mechanism].

OBJECTIVE: To study the mechanisms of curcumin alleviating oxidative stress and spleen apoptosis induced by overtraining in rats by regulating Kelch-like ECH-associated protein-1 (Keap1)-nuclear factor erythroid 2-related factor 2 (Nrf2)-antioxidant response element (ARE) signaling pathway. METHODS: Male Wistar rats of 7 weeks old were divided into control group (C group, 12), overtraining group (OM group, 11), curcumin + overtraining group (COM group, 14). The C Group did not undergo any exercise intervention. The OM and COM group underwent 8-week incremental load swimming training. During the training, rats in the COM group were treated with curcumin at the dose of 200 mg/(kg·d) in the volume of 5 ml/kg by gavage, and rats in the other groups were given an equal volume of solvent, 0.5% sodium carboxymethylcellulose. Twenty-four hours after the last training, the spleen index was calculated by weighing, the pathological changes of the spleen were observed by light microscopy, and the biochemical indicators of blood and spleen were detected. RESULTS: The spleen structure of C group was normal under light microscope; the spleen index of OM group was significantly lower than that of C group (P＜0.01) and pathological changes were obvious; the spleen index of COM group was significantly higher than that of OM group (P＜0.05) and histomorphological changes were relieved. Compared with C group, in OM group, serum corticosterone (Cor) level, spleen apoptosis level, malondialdehyde (MDA) concentration and the expression of proapoptotic Bcl-2 associated X protein (Bax) in spleen were increased (P＜0.05 or P＜0.01); the body weight, serum testosterone (T), superoxide dismutase (SOD) activity, the expressions of heme oxygenase-1 (HO-1) and anti-apoptotic B cell lymphoma-2 protein (Bcl-2) in spleen were decreased (P＜0.05 or P＜0.01); the expression of Nrf2 was not changed significantly (P＞ 0.05). Compared with OM group, in COM group, there were no significant changes in body weight (P＞0.05), serum T level, SOD activity, the expressions of Bcl-2, Nrf2 and HO-1 in spleen were increased (P＜0.05 or P＜0.01); serum Cor level, spleen apoptosis level, MDA concentration and the expression of Bax were decreased (P＜0.05 or P＜0.01). The change trend of T/Cor ratio between groups was consistent with the change of testosterone, and the change trend of Bcl-2/Bax ratio was consistent with the change of Bcl-2. CONCLUSION: The 8-week incremental load excessive swimming training aggravated spleen apoptosis, led to pathological changes and dysfunction of spleen. Curcumin can up-regulate expression of Nrf2 and HO-1, alleviate oxidative stress induced by overtraining, enhance Bcl-2 expression and attenuate Bax expression, thereby inhibiting excessive spleen apoptosis of rats, protecting the structure and function of spleen.

Excessive training induces molecular signs of pathologic cardiac hypertrophy.

Chronic exercise induces cardiac remodeling that promotes left ventricular hypertrophy and cardiac functional improvement, which are mediated by the mammalian or the mechanistic target of rapamycin (mTOR) as well as by the androgen and glucocorticoid receptors (GRs). However, pathological conditions (i.e., chronic heart failure, hypertension, and aortic stenosis, etc.) also induce cardiac hypertrophy, but with detrimental function, high levels of proinflammatory cytokines and myostatin, elevated fibrosis, reduced adenosine monophosphate-activated protein kinase (AMPK) activation, and fetal gene reactivation. Furthermore, recent studies have evidenced that excessive training induced an inflammatory status in the serum, muscle, hypothalamus, and liver, suggesting a pathological condition that could also be detrimental to cardiac tissue. Here, we verified the effects of three running overtraining (OT) models on the molecular parameters related to physiological and pathological cardiac hypertrophy. C57BL/6 mice performed three different OT protocols and were evaluated for molecular parameters related to physiological and pathological cardiac hypertrophy, including immunoblotting, reverse transcription polymerase chain reaction, histology, and immunohistochemistry analyses. In summary, the three OT protocols induced left ventricle (LV) hypertrophy with signs of cardiac fibrosis and negative morphological adaptations. These maladaptations were accompanied by reductions in AMPKalpha (Thr172) phosphorylation, androgen receptor, and GR expressions, as well as by an increase in interleukin-6 expression. Specifically, the downhill running-based OT model reduced the content of some proteins related to the mTOR signaling pathway and upregulated the ß-isoform of myosin heavy-chain gene expression, presenting signs of LV pathological hypertrophy development.

Protective effects of photobiomodulation against resistance exercise-induced muscle damage and inflammation in rats.

We investigated whether low-level laser therapy (LLLT) prior to or post resistance exercise could attenuate muscle damage and inflammation. Female Wistar rats were assigned to non-LLLT or LLLT groups. An 830-nm DMC Laser Photon III was used to irradiate their hind legs with 2J, 4J, and 8J doses. Irradiations were performed prior to or post (4J) resistance exercise bouts. Resistance exercise consisted of four maximum load climbs. The load work during a resistance exercise bout was similar between Control (non-LLLT, 225 ± 10 g), 2J (215 ± 8 g), 4J (210 ± 9 g), and 8J (226 ± 9 g) groups. Prior LLLT did not induce climbing performance improvement, but exposure to 4J irradiation resulted in lower blood lactate levels post-exercise. The 4J dose decreased creatine kinase and lactic dehydrogenase levels post-exercise regardless of the time of application. Moreover, 4-J irradiation exposure significantly attenuated tumor necrosis factor alpha, interleukin-6, interleukin-1ß, cytokine-induced neutrophil chemoattractant-1, and monocyte chemoattractant protein-1. There was minor macrophage muscle infiltration in 4J-exposed rats. These data indicate that LLLT prior to or post resistance exercise can reduce muscle damage and inflammation, resulting in muscle recovery improvement. We attempted to determine an ideal LLLT dose for suitable results, wherein 4J irradiation exposure showed a significant protective role.

Effectiveness of furosemide in attenuating exercise-induced pulmonary haemorrhage in horses when administered at 4- and 24-h prior to high-speed training.

BACKGROUND: Due to the high prevalence of EIPH in racehorses and its potential impact on the horse's health, furosemide administration is permitted up to 4-h prior to post time in most North American racing jurisdictions. Anecdotal reports suggest that administration of furosemide 24-h prior to strenuous exercise may be equally effective in decreasing the severity of EIPH. OBJECTIVES: To 1) compare the efficacy of furosemide in reducing the presence and severity of EIPH when administered 4- or 24-h prior to strenuous exercise 2) characterise electrolyte and blood parameters following administration of furosemide at 4- and 24-h prior to exercise. STUDY DESIGN: 3-way crossover. METHODS: Fifteen Thoroughbred racehorses received 5 mL of 0.9% NaCl or 250 mg of furosemide either 4- or 24-h prior to a 5-furlong simulated race. Blood samples were collected prior to and post-run for determination of furosemide, lactate, haemoglobin and electrolyte concentrations. One-hour post-race, an endoscopic exam and bronchoalveolar lavage (BAL) were performed. Horses were assigned an EIPH score based on predetermined criteria and the number of red blood cells in BAL fluid was determined. RESULTS: Endoscopic EIPH scores were lower in the 4-h vs. the 24-h (P = 0.03) furosemide groups. RBC counts in BAL fluid were lower in the 4-h furosemide vs. saline treatment groups (P = 0.01) but no difference was noted between the saline and 24-h furosemide groups (P = 0.3), nor between the 4- and 24-h groups (P = 0.5). MAIN LIMITATIONS: Small sample size and large range of running times for the 5-furlong work. CONCLUSIONS: While none of the treatments prevented EIPH, endoscopic scores and RBC counts in BAL fluid support the efficacy of furosemide in reducing the severity of EIPH. Endoscopic scores were lower in the 4-h furosemide group compared with 24-h administration. Red blood cell counts were lower in the 4-h furosemide group compared with saline treatment.