OBJECTIVE: To evaluate the mechanism of black plaster based on the theory of “open-close in the interstices” through the study of the vascular reactivity of the knee osteoarthritis model rabbits with cold blood coagulation and blood stasis syndrome. METHODS: The rabbit model of knee osteoarthritis with cold coagulation and blood stasis syndrome was prepared by combining cold stimulation with drug induction. Vascular effects of the periprosthetic arterial network（lower femoral artery

lateral superior genicular artery and inferior lateral genicular artery） in rabbits were closely observed by using color Doppler ultrasound techniques and blood flow indicators. Effects of Goupi plaster（manufacturer 1

manufacturer 2 and manufacturer 3 group） and black plaster matrix（matrix group） on the diameter

blood flow velocity and hemorheological indicators of the perigenicular artery network were investigated from 0 d to 15 d. RESULTS: After 15 d of treatment

the vascular diameter of the the lower femoral artery

the lateral superior genicular artery and inferior lateral genicular artery of the rabbits in the manufacturer 1

the manufacturer 2 and the manufacturer 3 groups and the matrix group increased

and the blood flow velocity increased

the whole blood viscosity and erythrocyte aggregation indicators showed the decreasing trend

and erythrocyte deformability indicators showed the increasing trend. CONCLUSIONS: Both the black plaster matrix and the Goupi plaster have the effects of inducing vascular effects of perigenicular artery network

suggesting that the black plaster matrix also plays a key role in promoting the “open-close in the interstices”.