重组人血小板型PLA_2体外抗菌活性研究

Study on in Vitro Antibiotic Activity of Recombinant Human Platelet Phospholipase A_2

目的观察重组人血小板型磷脂酶A2（PLA2）的体外抗菌活性。方法将不同浓度的重组PLA2与9种细菌在37％共同孵育2h，然后倾注琼脂板，次日记录每一琼脂板上的菌落生成数（CFU），计算出PLA2杀菌率和PLA2的最低杀菌浓度（MBC）。结果重组人血小板型PLA2对金黄色葡萄球菌、枯草杆菌、炭疽杆菌、表皮葡萄球菌、粪肠球菌等革兰氏阳性（G^＋）菌有较强杀菌作用，作用2h后PLA2的MBC范围为0．015～0．240μg／ml。对大肠杆菌、伤寒沙门氏菌、铜绿假单胞菌、变形杆菌等革兰氏阴性（G^-）菌则需要较高浓度的血小板型PLA2，作用2h后的MBC为30～90μg／ml。结论血小板型PLA2对G^＋菌有较强的杀菌作用，对G^＋菌的杀菌作用较弱。

Objective To observe the bactericidal effect of recombinant human platelet phospholipase A2 （ PLA2 ） in vitro. Methods Incubated bacteria solution with different concentration of recombinant PLA2 at 37℃ for 2 hours in a water bath. Then diluted the reaction solution and poured agar plates. Counted the colony formed unit and calculated the bacteria survival rate and the minimal bactericidal concentration（MBC） of the PLA2 at next day. Results The recombinant human platelet possessed potent bactericidal activity on the gram-positive （ G^＋ ） bacteria, such as Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus facecalis, Bacillus subtilis, Bacillus anthrax,its MBC were 0. 015 -0.24 μg/ml when incubated for 2 h. The PLA2 required for highly concentration to against gram-negative （G^-） bacteria, such as Escherichia coli, Salmonella typhi, Bacillus pyocyaneus, Bacillus proteus, its MBC were 30 -90 μg/ml when incubated for 2 h. Conclusion The recombinant human platelet PLA2 possesses potent bactericidal activity against G^＋ bacteria and weak bactericidal activity against G^- bacteria.