Objective: To observe the effects of Dendrobium officinale polysaccharides (DOP) on cardiac function and ability of myocardial contraction in the rabbits with coronary heart disease and discuss its therapeutic mechanisms. Method: Thirty clean grade healthy rabbits were randomly divided into control group

model group

DOP low-dose

middle-dose

and high-dose groups

with six rabbits in each group. Constriction rings were placed in left coronary artery to establish the model of coronary heart disease.DOP low-dose group

middle-dose group and high-dose group were respectively intragastrically administrated with 100

200

400 mg·kg-1DOP

once a day for continuous 21 days

while the control group and model group received the same volume of normal saline. Then left ventricular systolic pressure (LVSP)

left ventricular end-diastolic pressure (LVEDP)

maximal rates of increase/decline of left ventricular pressure (±dp/dtmax)

systolic blood pressure(BPs)

diastolic blood pressure(BPd)and ventricular mass index were recorded;alpha myosin (α-MHC)mRNA and beta myosin (β-MHC) mRNA expressions were measured by RT-PCR

and the expression of actin was measured by immunohistochemistry technology. Result: Compared with the control group

LVEDP

LVMI

and RVMI were increased in the model group (P<0.01

P<0.05)

while LVSP

±dp/dtmax

and BPs were reduced (P<0.01

P<0.05)

and the expression of α-MHC mRNA was reduced significantly (P<0.01) while the expression of β-MHC mRNA was increased (P<0.05)

and there were more myocardial cells of positive actin expression than those in control group. Compared with the model group

LVEDP was reduced in DOP low-dose group and middle-dose group(P<0.01

P<0.05)

LVSP

±dp/dtmax

and BPs were increased (P<0.01

P<0.05)

and the expression of α-MHC mRNA was increased significantly (P<0.01) while the expression of β-MHC mRNA was reduced (P<0.05)

there were fewer myocardial cells of positive actin expression than those in model group. Conclusion: DOP could restore ability of myocardial contraction and improve cardiac function to some degree.