Objective: To investigate the effects of storage lesion in apheresis platelets on platelet apoptosis and the changes of aggregation function, and analyze the relationships between the apoptosis and aggregation function.
Methods: Platelet samples were collected from 10 healthy donors with O blood group. Firstly, the effects of storage lesion in platelets on the platelet apoptosis were detected by flow cytometry. Then, using a multiplate analyzer, individual-donor Plt aggregation response to stimulation by the agonists ADP, Collagen, TRAP and ASPI was examined. Finally, the relationships between its apoptosis and aggregation function was analyzed by correlation regression analysis.
Results: By flow cytometry it was found that with the prolonging of storage time, the apoptosis ratio of platelets significantly increased in a time-dependent manner, the apoptosis rates of platelets on 2nd, 5th and 8th day were (2.87±0.31)%, (11.08±1.54)% and (27.99±2.76)% respectively (P<0.01). Compared with Day 2 platelets, the d 5 platelets stored for 5 d significantly decrease the aggregation response to stimnlation of collagen, TRAP, and ASPI. Compared with platelets stored for 5 d, platelets stored for 8 d significantly decreased the aggregation response to stimnlation of collagen, TRAP and ASPI (P<0.01). However, when stimulated by ADP, the aggregation response was similar among Day 2, Day 5 and Day 8 platelets. The rate of the aggregation function was also declined significantly when stimulated by collagen, TRAP, and ASPI, but not ADP. Further regression analysis showed that the aggregation function of apheresis platelet negatively correlated with the apoptosis (r=-0.9497, r=-0.9527, r= -0.9707 and r= -0.9352 respectively), and the correlation is very strong.
Conclusion: With the prolonging of storage time, the apoptosis ratio in platelets significantly increased. The aggregation function also is declined significantly when stimulated by collagen, TRAP, and ASPI, but not ADP. The aggregation function of apheresis platelets closly correlats with the apoptosis.