Plasma Creatine Kinase Activity Research Articles

Comparative Study of Physiological Changes in Turbot Scophthalmus maximus in Different Living Conditions

The aim of this study was to compare the organismal responses of farmed and wild-caught turbot, Scophthalmus maximus, based on analyses of biochemical plasma parameters, leukocyte profile, and histological tissue profile of gills, kidney, liver, intestine, and spleen, as well as gene expression of stress proteins in kidney and liver tissue. The results revealed significant differences in plasma triglycerides (TRIG), total protein (TP), albumin (ALB), globulin (GLOB), bilirubin (TBIL), creatinine (CRE) levels, creatine kinase (CK), and superoxide dismutase (SOD) activities that were higher, and A/G ratio, calcium (Ca) and phosphorus (P) concentrations, alkaline phosphatase (ALP), and glutathione peroxidase (GPx) activity, which were lower in farmed population. The neutrophil-leukocyte (N:L) ratio and gene expression of HSP70, HSP90, and WAP65-2 were increased in the wild-caught turbot. The wild-caught turbot were infested with the gill digenean parasite Dactylogyrus sp. and tapeworm Bothriocephalus scorpii. The obtained results provide valuable data for the assessment of the physiological responses of turbot for future comparative studies of the effects of various endogenous and exogenous factors on homeostasis of this species.

Eccentric Exercise Causes Specific Adjustment in Pyruvate Oxidation by Mitochondria.

The impact of eccentric exercise on mitochondrial function has only been poorly investigated and remains unclear. This study aimed to identify the changes in skeletal muscle mitochondrial respiration, specifically triggered by a single bout of eccentric treadmill exercise. Male adult mice were randomly divided into eccentric (ECC; downhill running), concentric (CON; uphill running), and unexercised control groups ( n = 5/group). Running groups performed 18 bouts of 5 min at 20 cm·s -1 on an inclined treadmill (±15° to 20°). Mice were sacrificed 48 h after exercise for blood and quadriceps muscles collection. Deep proximal (red) and superficial distal (white) muscle portions were used for high-resolution respirometric measurements. Plasma creatine kinase activity was significantly higher in the ECC compared with CON group, reflecting exercise-induced muscle damage ( P < 0.01). The ECC exercise induced a significant decrease in oxidative phosphorylation capacity in both quadriceps femoris parts ( P = 0.032 in proximal portion, P = 0.010 in distal portion) in comparison with the CON group. This observation was only made for the nicotinamide adenine dinucleotide (NADH) pathway using pyruvate + malate as substrates. When expressed as a flux control ratio, indicating a change related to mitochondrial quality rather than quantity, this change seemed more prominent in distal compared with proximal portion of quadriceps muscle. No significant difference between groups was found for the NADH pathway with glutamate or glutamate + malate as substrates, for the succinate pathway or for fatty acid oxidation. Our data suggest that ECC exercise specifically affects pyruvate mitochondrial transport and/or oxidation 48 h after exercise, and this alteration mainly concerns the distal white muscle portion. This study provides new perspectives to improve our understanding of the mitochondrial adaptation associated with ECC exercise.

Effect of Velocity-Based Heavy Resistance Exercise on Exercise-Induced Muscle Damage

&lt;p&gt;目的：探討動作速度流失率達20%即停止的速度依循高強度阻力運動對運動後之血液肌酸激酶 (CK) 活性、肌肉痠痛之視覺類比量表 (VAS) 分數、關節活動角度 (ROM) 與推動槓鈴速度為每秒1公尺的負荷重量 (V1 load) 之動作速度等運動誘發肌肉損傷 (EIMD) 指標之影響。方法：十二位大專男性柔道運動員採交叉、平衡次序的方式，執行3組、負荷為85% 1-RM、反覆至動作速度流失率達20%即停止 (VL20) 與反覆至力竭 (RF) 的臥推與深蹲運動；於運動前、運動後立即、運動後24與48小時量測各項EIMD指標，並紀錄運動執行情形。所測得數據以相依樣本t檢定及重複量數二因子變異數分析比較各項數值之差異。結果：VL20試驗執行第3組深蹲之動作速度流失率顯著低於RF試驗，並在運動後24小時之CK活性即與運動前無顯著差異，而RF試驗在運動後24小時之CK活性仍顯著高於運動後48小時；且VL20試驗在運動後各時間點的VAS分數皆顯著低於RF試驗、運動後24小時臥推V1 load之速度顯著高於RF試驗。結論：執行3組、85% 1-RM、控制動作速度流失率為20%的高強度阻力運動時，在執行深蹲後段會有較小的動作速度流失率，且在運動後立即至運動後48小時都有較低的痠痛感覺；即此方式能降低運動誘發肌肉損傷與加速運動後的恢復。&lt;/p&gt; &lt;p&gt;&amp;nbsp;&lt;/p&gt;&lt;p&gt;Purpose: To investigate the effect of velocity based heavy resistance exercise with 20% velocity loss on plasma creatine kinase (CK) activity, visual analog scale (VAS) of muscle soreness, range of motion (ROM), and against velocity 1 m/s load (V1 load) which commonly used as the indicators of exercise-induced muscle damage (EIMD). Methods: Twelve male collegiate judokas were recruited into the study. Participants performed 3 sets of heavy resistance exercise of bench press and squat at 85% of 1-RM, with the repetitions to 20% velocity loss (VL20) or failure (RF) in a counterbalanced crossover manner. The variables of EIMD and exercise load were measured at the time points of before exercise, immediately after exercise, 24 and 48 hr after exercise. Paired t-test and two-way ANOVA with repeated measurement were used to analyze the variables. Results: The velocity loss for the third set of squats in VL20 trail was significantly lower than in RF trail. The CK activity at 24 hours after exercise in VL20 trail was no significant difference as compared to before exercise. However, the CK activity at 24-hr after exercise in RF trail was significantly higher than 48-hr after exercise. The VAS scores at each time point after exercise in VL20 trail were significantly lower than in RF trail. Moreover, the velocity against the V1 load in bench press at 24-hr after exercise in VL20 trail was significantly higher than in RF trail. Conclusion: Controlling the repetition to 20% velocity loss during heavy resistance exercise for 3 sets of 85% of 1-RM enabled lower velocity loss in squat and lower muscle pain after exercise. It can minimize exercise-induced muscle damage and speed up recovery following resistance training.&lt;/p&gt; &lt;p&gt;&amp;nbsp;&lt;/p&gt;

Changes in blood bone markers after the first and second bouts of whole-body eccentric exercises.

The present study compared the first (EC1) and second (EC2) bouts of whole-body eccentric exercises to examine the effects of the magnitude of muscle damage on changes in blood bone markers. Fifteen sedentary young men performed nine eccentric exercises of arm, leg, and trunk muscles, and repeated them 2weeks later. Blood samples were taken before and 2h and 1-5days following each bout to analyze plasma creatine kinase (CK) activity and myoglobin concentration, serum tartrate-resistant acid phosphatase (TRAP), type 1 C-terminal telopeptide (CTX-1), procollagen type I N-terminal propeptide (P1NP), bone-specific alkaline phosphatase (BAP), undercarboxylated-osteocalcin (ucOCN), carboxylated-osteocalcin (cOCN), and leptin concentrations. All except ucOCN changed significantly (p<0.05) after both bouts. When comparing bouts for peak changes, P1NP (bone formation marker) and CTX-1 (bone resorption marker) increased less after EC2 (peak: 137±96% and 7±6%, respectively) than after EC1 (146±80% and 30±21%, respectively), whereas BAP (bone formation marker) increased more after EC2 (18±16%) than after EC1 (4±15%) (p<0.05). Leptin (49±58%) and cOCN (14±10%) increased more (p<0.05) after EC2 than after EC1 (-30±15%, 9±26%). Significant (p<0.05) correlations were evident between peak CK activity and peak CTX-1 (r=0.847), P1NP (r=0.815), BAP (r=-0.707), ucOCN (r=0.627), cCON (r=-0.759), and leptin (r=-0.740) changes after EC1, but many of these correlations disappeared after EC2. This was also found for the relationships between other muscle damage markers (myoglobin, muscle soreness, and muscle strength) and the bone markers. It was concluded that bone turnover was affected by eccentric exercise, but muscle damage was unfavorable for bone formation.

Acute effects of a typical rhythmic gymnastic training session on physiological parameters in Olympic athletes

The aim of this study was to evaluate the effects of a day with two separate training sessions (morning and afternoon) of rhythmic gymnastics on erythrocytes, leukocytes, muscle damage, oxidative stress, and hydration of Brazilian team [age 17.7 (±1.1) years; body height 165 (±0.5) cm; body mass 49.7 (±4.2) kg]. Heart rate and session-ratings of perceived exertion were used to monitor training intensity. Blood samples were collected immediately before (M1) and after (M2) the training day for analyzing erythrocytes, leukocytes, plasma creatine kinase activity, lactate dehydrogenase, alanine aminotransferase, aspartate aminotransferase, ferric reducing ability plasma, thyroid-stimulating hormone, and free T4. Saliva was collected for cortisol analysis. After 24 hours rest (M3), blood collection was performed to analyze creatine kinase and lactate dehydrogenase. The moderate-intensity training day induced significant elevations of total leukocytes (5,163.3 to 9,617.8), lymphocytes (1,752.7 to 2,729.7), neutrophils (2,873.9 to 6,163.6), monocytes (255.7 to 519.1), platelets (280,000.0 to 300,666.7), aspartate aminotransferase (13.1 to 25.6), lactate dehydrogenase (102.5 to 249.1), thyroid-stimulating hormone (1.0 to 3.2), and ferric reducing ability plasma (136.8 to 165.4), as well as significant reductions in red cells (4,691,111.1 to 4,497,777.8), hematocrit (42.1 to 39.3), and hemoglobin (12.9 to 12.5) at M2. There were also significant increases in creatine kinase (144.2 to 519.3) and lactate dehydrogenase (102.5 to 538.2) at M3. The average dehydration rate was 1.3%. A moderate-intensity day of training in rhythmic gymnastics of 8h21min duration caused hemolysis, leukocytosis, muscle damage, redox status perturbations, and insufficient hydration status. These findings show that athletes are exposed to physiological vulnerabilities that can possibly harm their performance and health.

American Ginseng Attenuates Eccentric Exercise-Induced Muscle Damage via the Modulation of Lipid Peroxidation and Inflammatory Adaptation in Males

Exercise-induced muscle damage (EIMD) is characterized by a reduction in functional performance, disruption of muscle structure, production of reactive oxygen species, and inflammatory reactions. Ginseng, along with its major bioactive component ginsenosides, has been widely employed in traditional Chinese medicine. The protective potential of American ginseng (AG) for eccentric EIMD remains unclear. Twelve physically active males (age: 22.4 ± 1.7 years; height: 175.1 ± 5.7 cm; weight: 70.8 ± 8.0 kg; peak oxygen consumption [peak] 54.1 ± 4.3 mL/kg/min) were administrated by AG extract (1.6 g/day) or placebo (P) for 28 days and subsequently challenged by downhill (DH) running (−10% gradient and 60% peak). The levels of circulating 8-iso-prostaglandin F 2α (PGF2α), creatine kinase (CK), interleukin (IL)-1β, IL-4, IL-10, and TNF-α, and the graphic pain rating scale (GPRS) were measured before and after supplementation and DH running. The results showed that the increases in plasma CK activity induced by DH running were eliminated by AG supplementation at 48 and 72 h after DH running. The level of plasma 8-iso-PGF2α was attenuated by AG supplementation immediately (p = 0.01 and r = 0.53), 2 h (p = 0.01 and r = 0.53) and 24 h (p = 0.028 and r = 0.45) after DH running compared with that by P supplementation. Moreover, our results showed an attenuation in the plasma IL-4 levels between AG and P supplementation before (p = 0.011 and r = 0.52) and 72 h (p = 0.028 and r = 0.45) following DH running. Our findings suggest that short-term supplementation with AG alleviates eccentric EIMD by decreasing lipid peroxidation and promoting inflammatory adaptation.

Potential Application of Low-Intensity Focused Ultrasound in Rapidly Relieving Delayed-Onset Muscle Soreness Induced by High-Intensity Exercise.

To evaluate the efficacy of low-intensity focused ultrasound (LIFU) treatment on rapid relief of delayed-onset muscle soreness (DOMS) triggered by high-intensity exercise. A total of 16 healthy male college students were randomly divided into two groups: the LIFU group (n=8) and the Sham group (n=8). After the exercise protocol, the LIFU group received treatment, which parameters included that the power output was 2.5W/cm2 , the frequency was 1MHz, and the treating time was 20minutes. The Sham group was treated with LIFU without energy output. Visual analog scale was used to evaluate the level of DOMS in every participant. The activities of plasma creatine kinase, lactate dehydrogenase, and the plasma concentration were measured by spectrophotometry. Tumor necrosis factor-α and interleukin-6 of serum were analyzed by enzyme-linked immunosorbent assay. The visual analog scale of quadriceps femoris and/or calf muscles in the LIFU group decreased significantly at 24 hours (P < 0.01) and 48 hours (P < .01) after the exercise protocol. Both the accumulation of lactic acid (P < .01) in muscle and the activity of lactate dehydrogenase (P < .01) reduced immediately after LIFU treatment. The activities of tumor necrosis factor-α and interleukin-6 24hours lowered in the LIFU group (P < .01). LIFU treatment could relieve muscle soreness rapidly and effectively in the early stages of DOMS. The application of LIFU may provide a potential strategy for clinical treatment for DOMS.

Can Skin Temperature Be Altered After Different Magnitudes of Eccentric Exercise-Induced Muscle Damage?

ABSTRACT Purpose: This study aimed to assess skin temperature (Tsk) changes after different magnitudes of exercise-induced muscle damage (EIMD) of the elbow flexor muscles and investigate whether Tsk is related to indirect markers of EIMD. Methods: Thirty healthy active men were randomly allocated to the mild (MiDG) (n = 15) or moderate (MoDG) (n = 15) muscle damage group. Muscle damage in elbow flexor muscles was induced by 10 (for MiDG) or 30 (for MoDG) maximal eccentric isokinetic contractions at 60 degrees/s. Tsk, maximal voluntary isometric contraction (MVIC), delayed-onset muscle soreness (DOMS), plasma creatine kinase (CK) activity, range of motion (ROM), and pressure pain threshold (PPT) were measured before and up to 72 hr after EIMD. Results: Tsk increased only immediately after EIMD (p < .05; f = 1.44) in the MoDG (4.2%) and MiDG (4.6%), returning to near baseline values 30 min after EIMD and remaining so thereafter. In addition, there was no intergroup difference (p > .05) at any of the times analyzed, or correlation between Tsk and most indirect markers of EIMD. Conclusions: In conclusion, Tsk should not be considered an indirect marker of mild or moderate muscle damage in active men, since alterations in this variable last less than 30 min after damaging exercise and showed no correlation with most indirect markers of EIMD.

Bioelectrical Phase Angle, Muscle Damage Markers and Inflammatory Response After a Competitive Match in Professional Soccer Players

Abstract Introduction. The purposes of this study were 1) to evaluate changes from baseline levels in bioelectrical phase angle (PhA) and markers of muscle damage and inflammation in professional players 36 h after a soccer match, and 2) to analyze the relationships between PhA and markers of muscle damage and inflammation in order to investigate if PhA might be a useful parameter to monitor recovery. Material and methods. Eighteen male professional soccer players participated in this study. Plasma lactate dehydrogenase (LDH) and creatine kinase (CK) activities, plasma C-reactive protein (CRP) and interleukin-6 (IL-6) concentrations, and PhA were measured before and 36 h after a competitive match. Results. Changes in LDH and CK 36 h after the match were greater than their reference change values (RCV). Changes in CRP and IL-6 were, however, lower than their corresponding RCV. 36 h after the match, significant correlations were observed between PhA and LDH (r = 0.714, p = 0.001), PhA and CK (r = 0.787, p = 0.000), and PhA and CRP (r = 0.554, p = 0.017). Conclusions. Although IL-6 and CRP have been traditionally analyzed together to monitor inflammation after intense exercise, since 36 h after the match they have already returned or started to return to baseline levels, the use of them alone is not a good option to monitor inflammation throughout recovery. PhA might be used as a predictor of muscle damage and inflammation, but further studies covering the whole recovery period are warranted.

Response of Knee Extensor Muscle-Tendon Unit Stiffness to Unaccustomed and Repeated High-Volume Eccentric Exercise.

The purposes of this study were to investigate the muscle-tendon unit stiffness response and to compare the stiffness with those of other indirect markers induced by two bouts of unaccustomed eccentric exercise. Eleven untrained men performed two bouts of 200 maximal eccentric contractions of the right quadriceps 4 weeks apart. Changes in stiffness, pain evoked by stretching and pressure, plasma creatine kinase (CK) activity, and muscle thickness were followed for 7 days after each bout. Stiffness and pain peaked immediately and 1 day after the first exercise bout, whereas CK and thickness were highest 4 and 7 days after the first exercise bout, respectively (p < 0.05 for all). Muscular pain, thickness, and stiffness responses were lower by 53.3%, 99%, and 11.6%, respectively, after the repeated bout compared to after the first bout (p < 0.05 for all), while CK activity response did not differ significantly between bouts. High responders for an increase in muscle-tendon unit stiffness showed a repeated-bout effect for stiffness, pain, and CK activity (by 29%, 65%, and 98%, p < 0.05 for all), but the repeated-bout effect was not that clear in low responders. These findings suggest that a repeated eccentric exercise bout effect on stiffness in quadriceps is mostly not associated with muscle pain and CK activity, but there are large individual differences.

Incidence, history and clinical findings of tibial neuropathy in German Holstein cows

The aim of this study was to document the occurrence, history, and clinical findings of tibial neuropathy in German Holstein dairy cows in order to yield information regarding the importance and etiology of this disorder in dairy herds in Central Germany. This prospective study was undertaken between January 2013 and October 2017 and included 88 German Holstein dairy cows with unilateral (UTN, n = 71) or bilateral (n = 17, BTN) tibial neuropathy. Data were collected from the history as well as the clinical and laboratory examinations. Three grades of paresis were defined. The percentage of cows with tibial neuropathy among all German Holstein dairy cows presented with disorders of the locomotor system in the study period amounted to 2.2 %. UTN was seen predominantly following dystocia or as a result of prolonged lateral recumbency in consequence to a primary disease. The majority of cases of BTN occurred in association with the resumption of cyclicity following calving. These were accompanied by clinical signs of a cauda equina syndrome. Increased plasma activities of creatine kinase (UTN 98 %; BTN 100 %) and aspartate aminotransferase (UTN 89 %; BTN 100 %) were observed in nearly all affected cows. Tibial neuropathy is a regularly occurring disorder in dairy herds in Central Germany. The condition results in pain and locomotor impairment and therefore constitutes a welfare concern. UTN and BTN have different causes, and the history combined with clinical signs (severity of paresis) provides etiological information. Increased enzymatic activities suggest a muscular involvement in the disease process.

SARCOCYSTOSIS IN A CAPTIVE FLOCK OF THICK-BILLED PARROTS (RHYNCHOPSITTA PACHYRHYNCHA) FROM 2005 TO 2016: MORBIDITY, MORTALITY, DIAGNOSTICS, AND MANAGEMENT STRATEGIES

Sarcocystosis was diagnosed in a captive flock of thick-billed parrots (Rhynchopsitta pachyrhyncha) at the Wildlife Conservation Society's Queens Zoo. Since the index case in 2005, 45% of mortalities in birds over 30 days of age were due to sarcocystosis. Sarcocystis falcatula was repeatedly identified as the causative agent. The disease predominantly affected younger adult parrots. Administration of antiparasitic medications prior to development of respiratory signs prolonged life in infected birds, but disease was fatal until utilization of a three-drug combination (pyrimethamine, trimethoprim-sulfamethoxazole, and ponazuril). This protocol may require in excess of 6 mo of therapy to achieve clinical resolution of active disease. Plasma creatine kinase activity was found to be the most useful test in diagnosing infection and monitoring response to therapy. Polymerase chain reaction (PCR) for apicomplexan organisms on antemortem whole blood, blood smears, or dried blood spots helped confirm suspected cases, but due to the poor sensitivity was sometimes misleading when assessing response to therapy or resolution of clinical disease. Preventive measures, focusing on exclusion and removal of Virginia opossums (Didelphis virginiana) from zoo grounds failed to curtail the occurrence of sarcocystosis in the flock. Other preventative steps, such as modification of feeding stations to exclude potential arthropod paratenic hosts and prophylaxis trials with diclazuril, appeared to successfully mitigate new infections. Given the diagnostic and therapeutic challenges, prevention of exposure to S. falcatula is essential to ex-situ conservation efforts for thick-billed parrots.

The effect of custom-fitted compression garments worn overnight for recovery from judo training in elite athletes

ABSTRACT This study investigated the effects of custom-fitted compression garments (CG) worn during recovery over a multi-day training camp in elite judo players (judoka). A single blind, placebo-controlled study was carried out in 11 elite judoka, using a two-way crossover design. Two three-day training camps were completed in CG and placebo conditions in a random order. Changes in performance and physiological markers were compared between conditions. Judoka were assessed before training for (maximal) isometric knee extension and grip strength, countermovement jump performance and bench-press velocity, alongside soreness, limb circumferences, plasma creatine kinase activity (CK) and perceived bruising. Measurements were repeated after 12, 36 and 43 h of training, whereupon judoka rated the effectiveness of each intervention. Knee extension and bench-press performance demonstrated significant familiarization (p < 0.001), and were excluded from subsequent analysis. Jump performance was unaffected by training (p > 0.05). Grip strength declined throughout training (p < 0.001), with peak decrements of −9.7% indicating mild muscle damage. Increases in bruising, CK and soreness demonstrated highly variable, if significant (p < 0.001) responses. Although CG were perceived as significantly more effective than placebo for recovery (p = 0.046), no effects were observed for any other outcome (p > 0.05). Compression conferred no statistically significant impact upon recovery markers in elite judoka throughout training. Muscle damage responses were inconsistent in this population. Individual athletes would be advised to monitor habitually-used performance measures while using CG to ascertain whether perceptual benefits translate into enhanced recovery. Highlights Compression garments were perceived as more effective for recovery than placebo by elite judoka. However, no measures of performance or muscle damage were enhanced by CG. Randori was associated with inconsistent muscle damage responses in elite judoka, while lower-body performance was not impaired. Individual athletes would be advised to monitor habitually-used performance measures while using CG to ascertain whether perceptual benefits translate into enhanced recovery.

Attenuation of doxorubicin-induced cardiotoxicity in Wistar rats by aqueous leaf-extracts of Chromolaena odorata and Tridax procumbens

Ethnopharmacological relevanceChromolaena odorata (L) King and Robinson and Tridax procumbens Linn are used in traditional medicine in the treatment of diabetes mellitus and hypertension. Aim of the studyThis study investigated the potential protective role of aqueous leaf-extracts of Chromolaena odorata and Tridax procumbens against cardiotoxicity induced by doxorubicin. Materials and methodsTo this end, their impact on plasma markers of cardiac integrity, cardiac markers of oxidative stress, cardiac lipids and electrolyte profiles, and activities of cardiac ATPases, lactate dehydrogenase and creatine kinase, were monitored in doxorubicin treated rats. Metformin (250 mg/kg body weight, orally) and both extracts (50, 75 and 100 mg/kg, orally) were daily administered for 14 days; while cardiotoxicity was induced with doxorubicin (15 mg/kg, intra-peritioneally, once on the 12th day of study). ResultsThe plasma activities of creatine kinase, lactate dehydrogenase and AST of Test control were significantly (p < 0.05) higher than those of the other groups. Also, the cardiac malondialdehyde, calcium, chloride, sodium, cholesterol and triglyceride concentrations of Test control were significantly (p < 0.05) higher than those of the others. However, the cardiac concentrations of ascorbic acid, reduced glutathione, magnesium and potassium, and cardiac activities of catalase, glutathione peroxidase, superoxide dismutase, Ca2+-ATPase, Mg2+-ATPase, Na+,K+-ATPase, creatine kinase and lactate dehydrogenase of Test control were significantly (p < 0.05) lower than those of the others. ConclusionsPre-treatment with the extracts and metformin elicited a cardioprotective effect, as indicated by the prevention of doxorubicin-induced cardiac oxidative stress and prevention of adverse alterations in plasma cardiac markers, cardiac lipids and electrolyte profiles, as well as improvement of the activities of cardiac ATPases, creatine kinase and lactate dehydrogenase.

Effect of Leg Eccentric Exercise on Muscle Damage of the Elbow Flexors after Maximal Eccentric Exercise.

The magnitude of muscle damage induced by maximal eccentric exercise is attenuated when the same exercise is repeated by homologous muscle of the ipsilateral or contralateral limb. It is not known if the muscle damage-protective effect is also transferred to nonhomologous muscles. The present study investigated the effects of unilateral knee extensor (KE) or flexor (KF) eccentric exercise on muscle damage induced by elbow flexor (EF) eccentric exercise of the ipsilateral or contralateral side. Young healthy sedentary men were assigned to four experimental groups (n = 13 per group) that performed five sets of six maximal eccentric contractions (MaxEC) of the KE or KF of the same or opposite side of the arm that performed MaxEC of the EF 1 wk later, and a control group that performed two bouts of MaxEC of the EF using a different arm for each bout separated by 1 wk. Changes in several indirect muscle damage markers were compared among the groups by mixed-design, two-way ANOVA. Changes in maximal voluntary concentric contraction torque, range of motion, muscle soreness, and plasma creatine kinase activity after KE or KF MaxEC were not different (P > 0.05) between legs, but greater (P < 0.05) after KF than KE MaxEC. The changes in the variables after EF MaxEC in the experimental groups were not different (P > 0.05) from the first bout of the control group but larger (P < 0.05) than the second bout of the control group, and no differences between the ipsilateral and contralateral sides were evident. These results showed that no protective effect on EF MaxEC was conferred by the leg exercises, suggesting that muscle damage protection was not transferred from KE or KF to EF.

Supplementation of guanidinoacetic acid and betaine improve growth performance and meat quality of ducks by accelerating energy metabolism

This study was conducted to investigate the effects of guanidinoacetic acid (GAA) and betaine on growth performance, meat quality and metabolism of ducks. A total of 384-one-day-old Cherry Valley meat ducks (55.75 ± 0.55 g) were randomly assigned to four treatments with 6 replicates of 16 ducks. Ducks were fed a basal diet (control) or a test diet supplemented with 0.6 g GAA/kg, 2.0 g betaine/kg, or 0.6 g GAA/kg + 2.0 g betaine/kg. The results showed that compared with the control group, GAA and betaine improved feed conversation ratio from day 1 to 14 and 1 to 35 and body weight at 35 days of age (p < .05). GAA and betaine increased breast muscle percentage while reduced abdominal fat percentage, and drip loss and shear force of breast muscle (p < .05). GAA and betaine lowered free serine, methionine, tryptophan and total amino acid contents in muscles, increased free serine, aspartic acid, phenylalanine and tryptophan contents in plasma (p < .05). There was a synergistic effect on non-esterified fatty acid, lactic acid and uric acid between GAA and betaine. GAA and betaine increased the creatine kinase activity in plasma and creatine and ATP content in breast muscle, decreased the lactate dehydrogenase and L-arginine: glycine amidino transferase activities (p < .05). In conclusion, supplementation of GAA and betaine improved the growth performance and meat quality of ducks by accelerating energy metabolism. There was a synergistic effect on NEFA, LA and UA concentrations in plasma of ducks between GAA and betaine. Highlights Supplementing GAA and betaine improved the growth performance and meat quality of ducks. Adding GAA and betaine accelerated the energy metabolism of ducks. There was a synergistic effect on non-esterified fatty acid, lactic acid and uric acid concentrations in the plasma of ducks between GAA and betaine.

Acute leucocyte, muscle damage, and stress marker responses to high-intensity functional training.

High-intensity functional training (HIFT) has become more popular, and the number of practitioners has increased; however, it remains unclear whether perturbations in the immune parameters occur, even after one single bout. Our aim was to examine acute leucocyte, muscle damage, and stress marker responses following a single 'Cindy' workout session, and compare the results between novice and experienced participants. Twenty-three HIFT practitioners (age 31.0 ± 1.0 years) completed the 'Cindy' workout. They were categorized as novice (3-8 months of experience; n = 10) and experienced (≥18 months; n = 13). White blood cell (WBC) count, plasma creatine kinase (CK) activity, blood cortisol level, and lactate concentration were measured. Blood analysis was performed before (pre-ex), immediately after (post-ex), 30 min after (post-30 min), and 24 h after (post-24 h) a single 'Cindy' workout session. WBC count was higher post-ex (6.8 to 11.8x103/μL) and returned to baseline values within post-30 min (p<0.01). Neutrophil (3.3 to 4.5x103/μL) and lymphocyte levels (2.8 to 5.9x103/μL) were higher post-ex and returned to baseline values after post-24 h, yet lymphocytopoenia (2.2x103/μL) was observed at post-30 min (p<0.01). CK increased post-ex (174.9 to 226.7 U.L-1) and remained elevated post-24 h. Cortisol (14.7 to 17.0 μg/dL) and lactate (1.9 to 13.5 mmol.l-1) responses increased post-ex, but only the lactate level was reduced at post-30 min (p<0.01). The experienced participants had higher WBC, lymphocyte, and cortisol concentrations post-ex than the novice ones (p<0.01). A single HIFT session elicited significant acute perturbations in WBC count, stress markers, and muscle tissue, which is like other similar regimens. Importantly, the experienced participants showed greater lymphocyte and cortisol responses than the novice ones.

Low Body Fat Does Not Influence Recovery after Muscle-Damaging Lower-Limb Plyometrics in Young Male Team Sport Athletes.

Aim: This study assessed the influence of fat mass to fat-free mass ratio (FM:FFM) on recovery from plyometric exercise. Method: After assessment of body composition, 20 male team sport players (age 20.7 ± 1.1 years; body mass 77.1 ± 11.5 kg) were divided into low- (n = 10; 0.11 ± 0.03) and normal- (n = 10; 0.27 ± 0.09) fat groups based on FM:FFM ratio. Thereafter, participants completed measurements of knee extensor torque at 60 and 240°∙s−1, countermovement jump flight time, plasma creatine kinase (CK) activity and perceived muscle soreness (VAS) before and at 0, 24 and 48 h after 10 × 10 maximal plyometric vertical jumps. Results: Evidence of muscle damage was confirmed by alterations in VAS, peak torque at 60 and 240°∙s−1 and flight time at 0, 24 and 48 h after plyometric exercise (P < 0.05). CK was increased at 0 and 24 h (P < 0.05) but returned to baseline values by 48 h. No time by group effects were observed for any of the dependent variables (P > 0.05). Conclusion: The current findings indicate that while muscle damage was present after plyometric exercise, the magnitude was similar across the two body composition groups. Applied practitioners can allow for a similar recovery time after plyometric exercise in those with low and normal body fat.

A potential therapeutic effect of catalpol in Duchenne muscular dystrophy revealed by binding with TAK1.

BackgroundDuchenne muscular dystrophy (DMD) is a progressive muscle disease caused by the loss of dystrophin, which results in inflammation, fibrosis, and the inhibition of myoblast differentiation in skeletal muscle. Catalpol, an iridoid glycoside, improves skeletal muscle function by enhancing myogenesis; it has potential to treat DMD. We demonstrate the positive effects of catalpol in dystrophic skeletal muscle.Methods mdx (loss of dystrophin) mice (n = 18 per group) were treated with catalpol (200 mg/kg) for six consecutive weeks. Serum analysis, skeletal muscle performance and histology, muscle contractile function, and gene and protein expression were performed. Molecular docking and ligand–target interactions, RNA interference, immunofluorescence, and plasmids transfection were utilized to explore the protective mechanism in DMD by which catalpol binding with transforming growth factor‐β–activated kinase 1 (TAK1) in skeletal muscle.ResultsSix weeks of catalpol treatment improved whole‐body muscle health in mdx mice, which was characterized by reduced plasma creatine kinase (n = 18, −35.1%, P < 0.05) and lactic dehydrogenase (n = 18, −10.3%, P < 0.05) activity. These effects were accompanied by enhanced grip strength (n = 18, +25.4%, P < 0.05) and reduced fibrosis (n = 18, −29.0% for hydroxyproline content, P < 0.05). Moreover, catalpol treatment protected against muscle fatigue and promoted muscle recovery in the tibialis anterior (TA) and diaphragm (DIA) muscles (n = 6, +69.8%, P < 0.05 and + 74.8%, P < 0.001, respectively), which was accompanied by enhanced differentiation in primary myoblasts from DMD patients (n = 6, male, mean age: 4.7 ± 1.9 years) and mdx mice. In addition, catalpol eliminated p‐TAK1 overexpression in mdx mice (n = 12, −21.3%, P < 0.05) and primary myoblasts. The catalpol‐induced reduction in fibrosis and increased myoblast differentiation resulted from the inhibition of TAK1 phosphorylation, leading to reduced myoblast trans‐differentiation into myofibroblasts. Catalpol inhibited the phosphorylation of TAK1 by binding to TAK1, possibly at Asp‐206, Thr‐208, Asn‐211, Glu‐297, Lys‐294, and Tyr‐293.ConclusionsOur findings show that catalpol and TAK1 inhibitors substantially improve whole‐body muscle health and the function of dystrophic skeletal muscles and may provide a novel therapy for DMD.

Enhanced cytokine expression and upregulation of inflammatory signaling pathways in broiler chickens affected by wooden breast myopathy.

Wooden breast (WB) myopathy in broiler chickens is a growing challenge for the poultry industry. Previous multi-omic data have implied that the pathogenesis of WB is associated with the activation of immune system and inflammatory response. However, the intricate mechanisms are not fully understood. This study was therefore conducted to systematically investigate the morphology, expression of cytokines as well as the underlying signaling pathways regulating the inflammatory response in pectoralis major (PM) muscle of WB myopathic broilers. wHistopathological changes, increased plasma creatine kinase and lactate dehydrogenase activities, elevated myeloperoxidase activity and overproduction of nitric oxide in muscle indicated the enhancement of muscle damage and inflammation in WB broilers. The messenger RNA (mRNA) expressions of inflammatory cytokines were dysregulated in PM muscle and contents of interleukin (IL)-1β, IL-8 and tumor necrosis factor-α were increased in serum of WB myopathic broilers, indicating this myopathy was associated with immune disorder and systemic inflammation response. Additionally, toll-like receptor (TLR) levels were upregulated, the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathway was activated and the mRNA expression levels of downstream inflammatory mediators were enhanced in PM muscle of WB myopathy affected birds. The results indicated an immune disorder and a systemic inflammation response in WB myopathic broilers, which might be related to a synergetic effect of TLRs and NF-κB pathway. © 2020 Society of Chemical Industry.