山柰酚拮抗血小板活化因子与其受体结合的作用

Inhibitiory effect of kaempferol against binding of platelet activating factor to its receptor

目的 :观察山柰酚对氚标记的血小板活化因子与血小板膜上受体结合作用的影响 ,试图证明该药为一新型血小板激活因子 (PAF)受体拮抗剂。方法 :以放射配基结合试验观察 [3 H]PAF与家兔血小板受体的特异性结合 ;分光光度法测定PAF诱发的血小板黏附强度 ;Fura 2荧光分光光度法测定PAF介导的兔多形核白细胞 (PMNs)内钙离子浓度的升高。结果 :山柰酚可浓度依赖地抑制 1,2 ,4nmol·L-1[3 H]PAF与血小板受体的特异性结合 ,IC50 分别为 30 .8,74 .6 ,92 .0 μmol·L-1;该药可明显抑制PAF诱发的兔血小板黏附及PMNs内游离钙升高 ,且均呈明显的量效关系 ,其抑制血小板黏附的IC50 为 6 5 μmol·L-1。结论 :山柰酚具抗PAF的作用 。

Objective: To observe the platelet activating factor (PAF) antagonistic effect of kaempferol. Method: The specific binding of [~3H]PAF to rabbit platelet receptor was investigated with radio ligand binding assay (RLBA). Platelet adhesion induced by PAF was measured with spectrophotometry. The elevation of inner free calcium concentration in rabbit polymorphonuclear leukocytes (PMNs) induced by PAF was determined with Fura-2 fluorescent technique. Result: The 1, 2 or 4 nmol·L^(-1) [~3H]PAF specific binding to rabbit platelet receptor was inhibited by Kae dosage dependently and the IC_(50) were 30.8, 74.6 and 92.0 μmol·L^(-1), respectively. The PAF induced reactions of rabbit platelet adhesion and PMNs inner free calcium concentration elevation were inhibited by Kae in a dose-dependent manner. The IC_(50) of Kae to inhibit platelet adhesion was 65 μmol·L^(-1). Conclusion: Kae is effective in inhibiting the action of PAF and it is a new PAF receptor antagonist.