Department of Bioengineering, Pennsylvania State University, University Park, Pennsylvania, USA.
Microcirculation. 2009 Nov;16(8):657-66. doi: 10.3109/10739680903133714.
The aims of this study were to examine the role of matrixmetalloproteinases (MMPs) in causing shedding of glycan components of the endothelial glycocalyx and delineate the efficacy of doxycycline as an inhibitor of white blood cell-endothelial cell (WBC-EC) adhesion and glycan shedding in postcapillary venules.
WBC-EC adhesion in postcapillary venules of mesentery (rat) was examined in response to superfusion with the chemoattractant, f-Met-Leu-Phe (fMLP). Glycan shedding was delineated by using fluorescently labeled microspheres (FLMs; 0.1 microm in diameter) coated with lectins and infused into the systemic circulation. The shedding of FLMs in response to fMLP was examined during superfusion with graded concentrations of doxycycline and the zinc chelator, ilomastat.
Superfusion of mesentery with 10(-7) M of fMLP caused a reduction in FLM adhesion due to shedding of the glycocalyx and a rise in WBC-EC adhesion. WBC-EC adhesion and FLM shedding were reduced with subantimicrobial concentrations of doxycycline equal to or greater than 0.5 muM with an EC(50) value of 0.15 microM. MMP activation was verified by inhibition of shedding and attenuation of circulating MMP substrate cleavage at the venular wall with the zinc chelator, ilomastat (GM6001, 2.6 microM; US Biological, Swampscott, Massachusetts, USA).
MMPs play a significant role in glycan shedding and WBC-EC adhesion, and doxycycline may stabilize the endothelial glycocalyx by inhibition of MMP activation.
本研究旨在探讨基质金属蛋白酶（MMPs）在导致内皮糖萼聚糖成分脱落中的作用，并阐明强力霉素作为白细胞-内皮细胞（WBC-EC）黏附和糖萼脱落抑制剂在后毛细血管静脉中的功效。
通过用趋化因子 f-Met-Leu-Phe（fMLP）灌注，检查肠系膜后毛细血管静脉（大鼠）中的 WBC-EC 黏附。通过用荧光标记的微球（FLM；直径 0.1 微米）包被凝集素并注入体循环，描绘聚糖脱落。在强力霉素和锌螯合剂伊洛马司他的梯度浓度灌注下，检查 fMLP 刺激下 FLM 的脱落。
用 10(-7) M 的 fMLP 灌注肠系膜会导致糖萼脱落，导致 FLM 黏附减少，WBC-EC 黏附增加。强力霉素的亚抑菌浓度（等于或大于 0.5 μM）可降低 WBC-EC 黏附和 FLM 脱落，其 EC(50) 值为 0.15 μM。通过用锌螯合剂伊洛马司他（GM6001，2.6 μM；美国生物制品公司，马萨诸塞州斯普林菲尔德）抑制脱落和减弱循环 MMP 底物在血管壁上的切割，验证了 MMP 激活。
MMPs 在聚糖脱落和 WBC-EC 黏附中起重要作用，强力霉素可能通过抑制 MMP 激活来稳定内皮糖萼。
