Loading solution prevents activation damage of human platelets before lyophilization

The current study aims to optimize the compositions of platelet activation-inhibitors for a loading solution of lyophilizing protectants and to establish a series of perfect pretreatment methods for platelet lyophilization. The optimal combination of six kinds of inhibitors and loading solutions of lyophilizing protectants, including prostaglandin E1 (PGE1), adenosine, l-arginine, phyticacid, bivalirudin, and cilostazol, was analyzed using the orthogonal experimental design. The values of the expression rates of p-selectin (CD62p) and platelet membrane glyeoprotein (PAC-1), as well as of platelet and mean platelet volume (MPV), were selected as indices of platelet activation. The values of CD62p and Pac-1 induced by thrombin were determined as indices of platelet reactivity. The maximal aggregation and slide platelet aggregation test (SPAT) induced by the inducer were calculated as indices of the aggregation function of platelets. Level I of the loading condition factor had no adverse action on MPV, CD62p, PAC-1, SPAT, and the maximum platelet aggregation rate. Level II of factors PGE1, l-arginine, phycicacid sodium, and Bivalirudin could inhibit the activation of platelets and enable them to retain their function. The results show that the optimal solution compounding was the third group. The loading solution, which includes plasma, 1 μM prostaglandin E1, 5 mM l-arginine, 0.5 mM phyticacid, and 0.5 μM bivalirudin, could prevent the activation damage of platelets before lyophilization.