Objective   To observe the characteristics of hemorheologic changes of hyperlipidemia rats at an early stage and to explore the mechanism of myocardial ischemic injury.    Methods   Seventy-two SD rats which were fed with high cholesterol diet (cholesterol+lard+pig bile salt) to result in hyperlipidemia model fell into HC group. Thirty-six SD rats which were fed with common diet fell into control group. The rats were fed for 10 to 90 d. At an interval of 10 d

9 time points were set. Therefore the 2 groups were randomly divided into 9 subgroups.At each time point

the changes of plasma lipids

cTnI

hemorheologic parameters

and pathological change of the rats’ myocardium and coronary vessel were assayed.   Results   The main characteristic of our models was hypercholesterolemia and high low-density-lipoproteins (LDL). With the extension of feeding time

plasma viscosity of HC group increased significantly

and erythrocyte deformability decreased. After fed with cholesterol for 50 d

myocardial ischemic injury occurred in the HC group. Correlation analysis revealed that the incidence of myocardial ischemic injury in hyperlipidemia rats was closely related with hypercholesterolemia and high low-density-lipoproteins.   Conclusion   The abnormal change of hemorheologic characteristics of hypercholesterolemia is a cause of myocardial ischemic injury.