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.

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.

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.