Objective: To investigate the bacteriostatic effect of platelet-rich plasma (PRP) and its derivative platelet gel (PG) supernatant on Escherichia coli in vitro and its relationship with platelet factor 4 (PF4).
Methods: Apheresis platelets donated by healthy volunteers were obtained from the Blood station of Lu an Blood Center as the source of PRP. The counts of platelet, white blood cell and red blood cell in PRP and its derivative PG supernatant were detected by automatic hematology analyzer. Bacterial growth of PRP and PG supernatants co-cultured with bacteria for different time was observed by plate coating culture method, and the contents of PF4 in PRP and PG supernatants were detected by ELISA.
Results: Apheresis platelets were collected from 28 healthy volunteers with a median age of 33 (21-56) years old. PRP can inhibit the growth of escherichia coli, but there were individual differences in antibacterial effect within 24 hours. PRP of 13 healthy volunteers had strong antibacterial effect at 24 hours, 7 cases had weak antibacterial effect at 24 hours, and 8 cases had no antibacterial effect at 24 hours. PG supernatant showed no significant individual difference, and all of them had bacteriostatic effect within 12 hours, but no bacteriostatic effect after 12 hours. There was no statistical difference in the bacteriostatic effect of PRP at 24 hours between healthy volunteers aged ≤30 years and >30 years (P>0.05), and there was no statistical difference between the white blood cell count ≤0.1×109/L and (0.1-1) ×109/L groups (P>0.05). There was significant difference in the bacteriostatic effect of PRP between the two groups with platelet content ≤1 000×109/L and >1 000×109/L (P<0.05). The platelet count in PRP was higher than that in PG supernatant ［(911.57±160.52) ×109/L vs 0］. The PF4 level in PRP was higher than that in PG supernatant (23623.34±9822.14 vs 6664.74±4065.83, P<0.05).
Conclusion: Both PRP and PG supernatant have antibacterial effects in Escherichia coli. The bacteriostatic effect of PRP was better than that of PG supernatant, and the platelet and PF4 contents in PRP were higher than those in PG supernatant, suggesting that the platelet and PF4 levels play an important role in bacteriostasis.
题目: 富血小板血浆及其衍生物的体外抑菌作用及其与PF4含量的关系.
目的: 探讨富血小板血浆（PRP）及其衍生物血小板凝胶（PG）上清在体外对大肠埃希菌的抑菌效果及其与血小板因子4（PF4）的关系.
方法: 从六安市中心血站获取健康志愿者捐献的单采血小板作为PRP来源。采用血细胞分析仪检测PRP及其衍生物PG上清中的血小板、白细胞和红细胞计数，平板涂布培养法观察PRP及PG上清与细菌共培养不同时间后细菌的生长情况，ELISA检测PRP及PG上清中血小板因子4（PF4）的含量.
结果: 收集28例健康志愿者的单采血小板，中位年龄33 (21-56)岁。PRP可以抑制大肠埃希菌的生长，24 h内抑菌效果存在个体差异。13例健康志愿者的PRP 24 h抑菌作用较强，7例志愿者24 h抑菌作用较弱，8例志愿者24 h无抑菌作用；PG上清无明显个体差异，均在12 h内发挥抑菌作用，12 h后无抑菌作用。不同年龄的健康志愿者（年龄≤30岁和>30岁）24 h PRP 抑菌效果比较无统计学差异（P>0.05），白细胞计数≤0.1×109/L和（0.1-1）×109/L两组间24 h PRP抑菌效果比较也无统计学差异（P>0.05）。24 h健康志愿者的PRP抑菌效果在血小板数≤1 000×109/L和>1 000×109/L两组中存在显著性统计学差异（P<0.05）。PRP中血小板数高于PG上清［（911.57±160.52）×109/L vs 0］。PRP中PF4含量高于PG上清（23623.34±9822.14 vs 6664.74±4065.83 ng/ml）.
结论: PRP及PG上清在大肠埃希菌中均可起到抑菌作用。PRP抑菌效果优于PG上清，且PRP中血小板以及PF4的含量均高于PG上清，PRP中血小板数及PF4含量在抑菌方面发挥重要作用.
Keywords: escherichia coli; platelet factor 4; platelet-rich plasma.