Effect of endurance training on the expression profile of circRNA-lncRNA-miRNA-mRNA in myocardial tissues of mice after exhaustive exercise

Objective:To clarify the effect of endurance training on the expression profile of circRNA-lncRNA-miRNA-mRNA in myocardial tissues of mice after exhaustive exercise.Methods:A total of 45 male C57BL/6 mice were randomly divided into control(C),low-strength endurance training(LSET)and high-strength endurance training(HSET)groups(n=15).The mice in the control group were not conducted to platform training.The mice in the LSET and HSET groups were conducted to platform training at 30%and 60%of exhaustive exercise once a day for 5 days a week,respectively.The exhaustion exercise was performed after 5 weeks of platform training.Total RNA was extracted from myocardial tissues,and the expression profile of circRNA-lncRNA-miRNA-mRNA in myocardial tissues was analyzed using Illimina transcriptome sequencing.Results:The distance and time of exhaustive exercise were longer in the LSET and HSET groups than in the control group,and the distance and time of exhaustive exercise were longer in the HSET group than in the LSET group(P<0.05).A total of 54 differentially expressed circRNAs(28 down-regulated and 26 up-regulated),7 differentially expressed lncRNAs(all down-regulated),3 differentially expressed miRNAs(1 down-regulated and 2 up-regulated)and 99 differentially expressed mRNAs(81 down-regulated and 18 up-regulated)were identified by transcriptome sequencing(P<0.05).Interaction network analysis revealed that ENSMUSG00000113041,MSTRG.79740,mmu-miR-374c-5p,18 down-regulated mRNAs and 3 up-regulated mRNAs formed a regulatory network.GO functional analysis revealed that the differentially expressed mRNAs were mainly enriched in primary metabolic processes and macromolecular synthesis and metabolic processes.KEGG pathway analysis revealed that the differentially expressed mRNAs were mainly enriched in complement and coagulation cascade pathways,estrogen signaling pathway and glucagon signaling pathway.Conclusion:Endurance training could alter the expression profile of circRNA-lncRNA-miRNA-mRNA in myocardial tissues of mice after exhaustive exercise,and these differentially expressed RNAs form a regulatory network that affects cardiomyocyte synthesis and metabolism and thus participates in the regulation of myocardial injury.

A Yang-invigorating compound mixture alters neurotransmitters in rat telencephalon after exercise-induced fatigue

The aim of this study was to observe the changes in monoamine and amino acid neurotransmitters in the telencephalon of rats at four functional states after exhaustive exercise and treatment with a Yang-invigorating compound recipe.The main components of this Chinese traditional medicine preparation included Radix Ginseng,Rhizoma Chuanxiong,Fructus Schisandrae,Cortex Cinnamomi,Cornu Cervi Pantotrichum,Radix Morindae Officinalis,and Gecko.This experiment showed that dopamine（DA）,5-hydroxyindole acetic acid（5-HIAA）,and γ-aminobutyric acid levels noticeably decreased,while DA/5-hydroxytryptamine（5-HT） increased.Furthermore,glutamate（Glu） and Glu/γ-aminobutyric acid significantly increased after 1 hour of exercise in rats in the exercise ＋ medication group.The 5-HT and 5-HT/5-HIAA levels noticeably decreased,and DA/5-HT and Glu levels showed a robust and significant increase immediately after exhaustive exercise.The 5-HT,5-HT/5-HIAA levels sharply decreased,while DA/5-HT,Glu and γ-aminobutyric acid levels increased at 12 hours after exhaustion recovery.The results prove that Chinese herbal formula for strengthening Yang can induce changes in neurotransmitters in the telencephalon of rats after exhaustive exercise during the recovery process,and further improve central nervous system function.

Hippocampal ultrastructural changes and apoptotic cell death in rats following endurance training and acute exhaustive exercise

BACKGROUND： Exhaustive exercise can lead to apoptosis of skeletal muscle cells and myocardial cells as a result of pathological changes in the corresponding cellular ultrastructure. It is hypothesized that such changes could also occur in neurons. OBJECTIVE： To observe brain cell apoptosis and ultrastructural changes in hippocampal neurons in rats following endurance training and acute exhaustive exercise. DESIGN, TIME AND SETTING： A randomized, controlled, morphological analysis was performed at the Medical Laboratory Center of Zhengzhou University between July and November 2007. MATERIALS： Forty male, 8-week-old, Sprague Dawley rats were included in this study. METHODS： Endurance training consisted of treadmill running once a day, 6 days a week, for 4. weeks. For acute exhaustive exercise, graded treadmill running was conducted. Rats were exposed to exercise at an increasing speed （10 m/min, increasing to 20 and 36 m/min for moderate- and high-intensity exhaustive exercise, respectively, and then was continued until exhaustion）. A total of 40 rats were evenly distributed into the following 4. groups： Group A rats were not exercised; Group B rats were not trained but sacrificed 24 hours after acute exhaustive treadmill running exercise; Group C-rats were subjected to endurance training and sacrificed immediately after acute exhaustive treadmill running exercise; Group D rats were subjected to endurance training and sacrificed 24 hours after acute exhaustive treadmill running exercise. MAIN OUTCOME MEASURES： Apoptotic cell death was detected by the TUNEL method and hippocampal neuronal ultrastructural change was observed through using transmission electron microscopy. RESULTS： All 40 rats were included in the final analysis. Subsequent to exhaustive exercise, rat cerebral cortex and hippocampal neurons appeared contracted and degenerated. In addition, high amount of lipofuscin was visible in the hippocampal region, Necrotic neurons encased by glial cells appeared in the cerebral cortex and hippocampus. Glial cells exhibited different degrees of swelling. Subsequent to exhaustive exercise, brain cell apoptosis rate significantly increased, and reached over 30% in some regions, compared with group A （P 〈 0.05）. No significant difference in apoptosis rate existed between groups B, C, and D （P 〈 0.05）. CONCLUSION： Endurance training and acute exhaustive exercise cause, to some degree, injuries to glial cells, resulting in apoptosis of numerous brain cells. Subsequent to exhaustive exercise, high amounts of lipofuscin appear in the hippocampus, indicating that exhaustive exercise possibly contributes to neural cell aging or dysmetabolism.

Evaluation of silymarin extract from Silybum marianum in mice: anti-fatigue activity

Silymarin has been used for centuries for its hepatoprotective properties. The specific objective of this study was to evaluate the anti-fatigue properties of silymarin. The silymarin was administered orally at doses of 50, 100, and 200 mg/kg for 4 weeks;the fatigue level and exercise performance were evaluated using exhaustive swimming time and pole-climbing time, as well as levels of plasma lactate, ammonia, glucose, creatine kinase(CK), serum urea nitrogen(SUN), blood lactic acid(BLA), muscle glycogen(MG), and liver glycogen(LG) contents after an intensive swimming session. The results demonstrated that silymarin treatment decreased the BLA and SUN levels while increased the LG and MG levels. In addition, silymarin decreased plasma lactate and ammonia levels and CK activity after swimming test, this is related to the mechanism that increases energy storage(as glycogen) and release(as blood glucose), and decreases plasma levels of lactate, ammonia, and CK. The observation of the skeletal muscle structures of mice also confirmed that skeletal muscles became more damaged in the control group compared with the silymarin-treated mice after prolonged endurance exercise. Therefore, it is reasonable to infer that silymarin may bear potential pharmacological effects in combating fatigue.

Detraining after tumor-bearing accelerates tumor growth while continuous training decreases tumor growth in mice

Objective:Previous studies have shown that exercise suppresses tumor growth.However,the effects of exercise with different intensities and exercise detraining after tumor-bearing on tumor progression remain unclear.The purpose of this study was to investigate the effects of continuous and disrupted free and exhausted swimming training after tumor-bearing on tumor progression in melanoma B16-F10-bearing C57BL/6 mice.Methods:C57BL/6 mice were subjected to free or exhausted swimming exercise training for 4 weeks prior to the injection of melanoma B16-F10 cells.Subsequently,the B16-F10-bearing mice were maintained with training consisting of free or exhausted swimming or without exercise for 2 weeks during the tumor challenge.Results:The tumor weight was increased by 42%and 109%in mice with 4-week exhausted swimming prior to B16-F10 tumor cells inoculation followed by 2-week training cessation compared with the tumor-bearing control(P<.05)and continuous training groups(P<.01).Tumor weights in groups with exercise detraining after tumor cell inoculation tended to be increased,while the proliferation of splenic T lymphocytes tended to be decreased compared with the group that maintained exercise intensity.After 6-weeks continuous free or exhausted swimming training,the tumor weight of mice was decreased and the proliferation of splenic T lymphocytes was increased compared with the tumor-bearing control group.The frequency of natural killer cells in tumors was increased in all exercise training groups of mice.Conclusions:These results suggest that maintaining exercise intensity after tumor-bearing slows tumor growth in mice,possibly because of the enhanced proliferative activity of splenic lymphocytes rather than natural killer cell infiltration.However,detraining after tumor-bearing might accelerate tumor progression because of the reduced proliferation of splenic T lymphocytes.

Influence of Intravenous Injection of Hydroxyapatite on Mouse Movement Ability

Lactic acid is usually formed during strenuous exercise, and a large amount of lactic acid and slow anaerobic glycolysis in muscle lead to limitations of movement ability. Hydroxyapatite（HAp） is an alkaline inorganic material with a good biocompatibility. It slowly degrades in vivo and releases trace amounts of calcium ions, reducing cell damage by reacting with polylactic acid and neutralizing local acid environment. Whether HAp can reduce the concentration of lactic acid in vivo and improve movement ability is not yet clear. Here, after eight days of training, 40 mice were randomly divided into four groups： control, distilled water, sodium bicarbonate and HAp group. After one day of rest, the mice were intravenously injected via the lateral tail veins with 1 ml distilled water, sodium bicarbonate and HAp suspension（2.2 mg/ml）, respectively, and subjected to a swimming exhaustive experiment（load 10%）. The swimming time of mice in the water, under water and total time were recorded. The exhaustive exercise mice were immediately subject to abdominal cavity anaesthesia. The concentrations of blood, gastrocnemius and myocardial lactic acid as well as serum LDH activity were detected. We demonstrate that HAp can significantly prolong swimming time and improve serum LDH activity, but does not affect lactic acid concentration. In conclusion, intravenous injection of HAp nanoparticles can significantly improve the exhaustive swimming ability of mice mainly because of the elevated blood LDH activity induced by HAp.

Changes in energy metabolism in the quadriceps femoris after a single bout of acute exhaustive swimming in rats： a 31p-magnetic resonance spectroscopy study

Background Little is known about the value of 31P-magnetic resonance spectroscopy （31P-MRS） in in vivo assessment of exhaustive exercise-induced injury in skeletal muscle.We aimed to evaluate the value of a 31P-MRS study using the quadriceps femoris after a single bout of acute exhaustive swimming in rats,and the correlation between 31P-MRS and histological changes.Methods Sixty male Sprague-Dawley rats were randomly assigned to control,half-exhaustive,and exhaustive exercise groups.31P-MRS of the quadriceps femoris of the right lower limb was performed immediately after swimming exercise to detect Pi,PCr,and β-ATP.The Pi/PCr,Pi/β-ATP,PCr/β-ATP,and PCr/（PCr＋Pi） were calculated and pH measured.Areas under the receiver operating characteristic curve （AUCs） were calculated to evaluate the diagnostic potential of 31P-MRS in identifying and distinguishing the three groups.HE staining,electron microscopy and desmin immunostaining after imaging of the muscle were used as a reference standard.The correlation between 31P-MRS and the mean absorbance （A value） of desmin staining were analyzed with the Pearson correlation test.Results Pi,PCr,Pi/PCr,and PCr/（PCr＋Pi） showed statistically significant intergroup differences （P＜0.05）.AUCs of Pi,PCr,Pi/PCr,and PCr/（PCr＋Pi） were 0.905,0.848,0.930,and 0.930 for the control and half-exhaustive groups,while sensitivity and specificity were 90％/85％,95％/55％,95％/80％,and 90％/85％,respectively.The AUCs of Pi,PCr,Pi/PCr and PCr/（PCr＋Pi） were 0.995,0.980,1.000,and 1.000 for the control and exhaustive groups,while sensitivity and specificity were 95％/90％,100％/90％,100％/95％,and 100％/95％,respectively.The AUCs of Pi,PCr,Pi/PCr,and PCr/（PCr＋Pi） were 0.735,0.865,0.903,and 0.903 for the half-exhaustive and exhaustive groups,while sensitivity and specificity were 80％/60％,90％/75％,95％/65％,and 95％/70％,respectively.In the half-exhaustive group,some muscle fibers exhibited edema in HE staining,and the unclear Z-discs and the mitochondria with vacuolar degeneration under electron microscopy.Compared with the half-exhaustive group,muscle fiber edema was increased in the exhaustive group,and the Z-discs were broken and the mitochondria exhibited marked vacuolar degeneration under electron microscopy.There were significant difference in A values of desmin staining in the right vastus lateralis among the control,half-exhaustive,and exhaustive groups with 0.58±0.06,0.30±0.04,and 0.21±0.02,respectively （P＜0.05）.Histological examination also showed injury-induced changes in the vastus lateralis among the different intensities groups.Statistically a moderate correlation between 31P-MRS and desmin was observed,the correlation coefficients of Pi,PCr,Pi/PCr,and PCr/（PCr＋Pi） were-0.706,0.709,-0.726,and 0.791,respectively （P＜0.01）.Conclusions 31P-MRS can effectively reflect the changes in energy metabolism in the skeletal muscle after a single bout of acute exhaustive swimming in rats.Based on the significant correlation between 31P-MRS parameters and histological changes,the changes of Pi,PCr,Pi/PCr,and PCr/（PCr＋Pi） can indirectly reflect the degree of exercise-induced injury.

Difference in the anti-fatigue effect of moxibustion at different acupoints in one-off exhausted rats

Objective:To explore the difference in the anti-fatigue effect of moxibustion at different acupoints through observing the impacts of moxibustion at"Shènshù(肾俞BL23)","Zúsānlǐ(足三里ST36)","Guānyuán(关元CV4)"and"Shénquè(神阙CV8)"on energy metabolic indexes in the one-off exhausted rats.Methods:A total of 56 SPF male rats were randomized into 7 groups,named a blank group,a model group,a non-acupoint group,a"BL23"group,a"ST36"group,a"CV4"group and a"CV8"group,8 rats in each group.The one-off exhaustion model was established by weight-bearing swimming experiment.Right after the exhaustive swimming of rats in each intervention group,the mild moxibustion was applied at the corresponding acupoints for 15 min immediately.4 h after the exhaustive swimming,the blood was collected from the femoral artery and the quadriceps femoris of the left hindlimb was stripped.The levels of blood lactate(BLD),lactate dehydrogenase(LDH),creatine kinase(CK)and blood urea nitrogen(BUN),the expressions of adenosine triphosphatease(ATP),fructose-6-phosphofructokinase(PFK)and malomdialdehyde(MDA)in the quadriceps femoris and the activity of superoxide dismutase(SOD)and catalase(CAT)were detected.Results:Compared with the model group and the non-acupoint group,the levels of serum BLD,LDH,CK and BUN were all lower those in the"BL23"group,the"ST36"group,the"CV4"group and the"CV8"group,indicating a statistical significance(all P<0.05).Compared with the model group and the nonacupoint group,PFK was higher in the"BL23"group,indicating a statistical significance(both P<0.05).Compared with the model group and the non-acupoint group,PFK was higher in the"ST36"group and the"CV4"group,indicating a statistical significance(all P<0.05).Conclusion:It was found in the research that moxibustion at"BL23""ST36""CV4"and"CV8"regulated the energy metabolism in the one-off exhausted rats so as to bring the anti-fatigue effect into play and the effect was different among the acupoints.Moxibustion at"CV8"may work on the prevention of the protein decomposition in the skeletal muscle and moxibustion at"BL23"may be against the oxidation in the skeletal muscle.