Objective To observe the effect of preventative moxibustion on cardiomyocytes in mice experiencing different intensities of exercise.Methods Kunming mice were randomly divided into blank control(n=10)

blank-moxibustion(n=10)

moderate-intensity exercise(MIE)model(n=8)

MIE-moxibustion(n=9)

exhausted-exercise model(n=8)

and exhausted-exercise moxibustion(n= 8)groups.Preventative moxibustion was applied to "Zusanli"(ST 36)and "Guanyuan"(CV 4)for 5min

once daily(except Saturdays or Sundays)for 3weeks.The apoptotic cardiomyocytes were detected by light microscope after terminal deoxynucleotidyl transferase mediated dUTP-biotin nick end labeling(TUNEL staining)

and the ultrastructure of cardiomyocytes was observed by using transmission electron microscope.Results Compared with the blank control group

the rates of the apoptotic cardiomyocytes were considerably increased in both MIE and exhausted-exercise model groups(P<0.05).Comparison between the MIE model and MIE-moxibustion groups and between the exhausted-exercise model and exhausted-exercise moxibustion groups showed that the apoptotic rates of cardiomyocytes were significantly lower in the two moxibustion groups than in the two model groups(P<0.05).In mice experiencing preventative moxibustion

the injured state of the cardiomyocytes including dissolved myofilaments of myocardial fibers

disorder of arrangement and increased interspace of myofilaments

and decreased number of partial myocardial bundles

and the increase of matrix electron density was relatively milder in comparison with their individual exercise model groups.Conclusion Preventative moxibustion may reduce MIE and exhausted exercise induced apoptosis of cardiomyocytes in mice and lessen myocardial injury.