Inhibition of shear-induced platelet aggregation in rat by tetramethylpyrazine and salvianolic acid B.

Tetramethylpyrazine (TMP) and salvianolic acid B (SAB) are effective ingredients of Rhizoma Ligustici chuanxiong Hort. and Radix Salviae miltiorrhizae Bge., accordingly. The inhibitive effects of TMP, SAB and their combination on shear-induced platelet aggregation (SIPA) were investigated in the present study. SD rats were used as blood donors to collect anticoagulated blood, the concentration of platelet-rich-plasma (PRP) was adjusted to 5 x 10(5) microl. HAAKE rheometer RS 600 with sensor C60/0.5 degrees was used as shear generator. Different doses of TMP and SAB and their combinations were added to the PRP. After constant shear of 15 Pa at 37 degrees C for 360 seconds, PRP was transferred to a platelet aggregometer and SIPA was determined by turbidity. SIPA was inhibited by TMP and SAB in a dose-dependent manner. SIPA was decreased from 48.6 +/- 4.6% of the control to 12.5 +/- 2.1% in the presence of TMP (1.46 mM) and SAB (10 microM) (P < 0.0001). In conclusion, TMP and SAB have additive effects on inhibiting platelet aggregation induced by high shear stress.