Objective: To investigate the mechanism of N- Arachidonoylethanolamine (ANA) on inhibiting platelets (PLT) apoptosis under standard blood bank storage conditions.
Methods: Samples taken from collected apheresis PLT by the Amicus instrument were split into three parts. An aliquot of 0.5 μmol/L ANA were added to one part of storage PLT as the ANA group; an aliquot of 0.5 μmol/L ANA and 1 μmol/L SR141716 was added to the another part as the ANA + SR141716 group; and the third part without ANA and SR141716 as the control group. These samples were stored on a flat-bed shaker at (22 ± 2) ⁰C for 7 days. The expression of phosphatidyl serine (PS) positive, phospho (p)-Akt, Akt, p-Bad, Bad, caspase-3, caspase-9, cytochrome C (Cyt-C) and BCL-XL interaction with Bak were detected.
Results: The rate of PLT PS positive in ANA group decreased significantly than that in control group[ (8.29 ± 1.44) % vs (14.24 ± 2.47) %, P<0.05]. The release of Cyt-C from mitochondria to cytosol in ANA group decreased significantly compared with control group[ (3.29 ± 1.44) % vs (15.24 ± 3.40) %, P<0.05]. Also the expressions of p-Akt and p-Bad in ANA group increased significantly than those in control group[ (71.33 ± 10.26) % vs (35.00 ± 6.00) %, P<0.05; (39.00 ± 9.64) % vs (10.33 ± 1.53) %, P<0.05, respectively]. Higher amounts of Bak protein were co-precipitated with BCL-XL in ANA group than that in control group (about 2.6 fold, P<0.05). The expressions of cleaved caspase- 9 and caspase- 3 in ANA group decreased significantly than those in control group[ (9.63 ± 1.47) % vs (23.24 ± 2.47) %, P<0.05; (6.30 ± 1.40) % vs (13.20 ± 2.50) %, P<0.05, respectively]. There were no significantly changes between ANA+SR141716 and control groups (P>0.05).
Conclusion: ANA protected PLTs from apoptosis as a result of inhibiting the release of Cyt-C from mitochondria to cytosol by modifying the expressions of apoptosis-relative proteins.