Objective: To study the effects of total diterpenoids from Rabdosia japonica var. glaucocalyx (TD) preconditioning on myocardial ischemia/reperfusion injury (MI/RI). Method: Twenty-four rabbits were randomly divided into four groups

sham group (group A)

I/R group(group B)

Danshen dripping pills(DS) group(group C)and TD group (group D). Group A and B were administered distilled water (5 mL·kg-1·d-1) intragastrically daily for 7 days prior to the operation. Rabbits in group C

D underwent the same surgical procedure as those in group B

but received respectively oral DS (37.8 mg·kg-1·d-1) and TD (4.76 mg·kg-1·d-1)

7 days before the operation. Ultrastructure was observed by light microscopy and electron microscopy. TUNEL staining detected myocardial cell apoptosis index. Immunohistochemisty determined expression of apoptosis-related protein B cell lymphoma/leukemia-2(Bcl-2) and Bcl-2 associated x protein(Bax). Result: Apoptosis index of myocardial cells in group C and D is respectively 10.93% and 9.87%

compared with group B (18.40%)the difference was obvious(P<0.05). Immunohistopathological studies showed that A of Bcl-2 in group C

D was 41.03

52.09

compared with group B (29.47) (P<0.05). Conclusion: TD may reduce MI/RI in rabbit model and have protective effects on myocardium.