中文摘要：

目的观察血小板因子4（PF4）对THP-1单核源性巨噬细胞基质金属蛋白酶9（MMP-9）表达的影响,并初步探讨其机制。方法佛玻酯诱导THP-1细胞分化成巨噬细胞。巨噬细胞经不同浓度PF4（0-200μg/L）处理一定时间后,RT-PCR和Western blot检测MMP-9和Toll样受体4（TLR4）表达。为了研究TLR4在其中的作用,细胞经TLR4阻断剂预处理30 min后,再与PF4孵育特定时间,检测MMP-9表达。结果与对照组比较,50μg/L PF4即可显著上调巨噬细胞MMP-9 mRNA和蛋白水平,至100μg/L时,MMP-9 mRNA和蛋白表达达到最大效应水平,分别较对照组增高约3.8倍（P〈0.001）和1.5（P〈0.01）倍。PF4（100μg/L）也较对照组显著上调TLR4 mRNA和蛋白水平。而加入TLR4阻断剂后可逆转PF4诱导的巨噬细胞MMP-9表达上调,其mRNA和蛋白水平分别较PF4单独孵育组降低约26%和21%（P均〈0.05）。结论 PF4可能通过TLR4上调巨噬细胞MMP-9的表达。

英文摘要：

Aim To investigate whether platelet factor 4（ PF4） modulates the matrix metalloproteinase-9（ MMP-9） expression of macrophages. Methods THP-1 monocytes were differentiated into monocyte-derived macrophages by phorbol 12-myristate 13-acetate（ PMA）. After incubation with PF4（ 0 - 200 μg /L）,the MMP-9 expression of macrophages was determined by reverse-transcription polymerase chain reaction（ RT-PCR） and Western blot. To determine the role of toll-like receptor 4（ TLR4） in the regulation of MMP-9 expression,macrophages were pretreated with TLR4 blocker for 30 min,then incubated with PF4. Results Macrophages that were untreated showed a relatively low MMP-9 and TLR4 mRNA or protein levels; treatment of macrophages with PF4 increased MMP-9 and TLR4 expression. However,the high levels of MMP-9 and TLR4 expression induced by PF4 were significantly attenuated in the presence of TLR4 blocker.Conclusions PF4 may up-regulate MMP-9 expression in macrophages via TLR4.