ABSTRACT
<p><b>AIM</b>To investigate the role of TNF-alpha in vascular endothelial cells injury mediated by freezing/thaw ing PMN.</p><p><b>METHODS</b>Freezing/thawing cell model was founded using rat PMN isolated by dextran sedimentation technique and VEC cultured in vitro. The injury level of VEC was indicated by measuring activity of LDH in medium. The number of frozen/thawed PMN adhering to VEC was counted with Phagocytizing reactive dyes the degree of frozen/thawed PMN and VEC adhesion. Expression of LFA-1 on the surface of frozen/thawed PMN was analyzed with flow cytometry.</p><p><b>RESULTS</b>TNF-alpha could obviously upregulate expression of LFA-1 on surfaced of frozen/thawed PMN. Upregulation of LFA-1 expression promoted adhesion of frozen/thawed PMN and normal VEC,and aggravated VEC injury. Monoclonal antibody against LFA-1 could partly block adhesion of frozen/thawed PMN and normal VEC,and attenuate VEC injury.</p><p><b>CONCLUSION</b>TNF-alpha can promote expression of LFA-1 on surface of frozen/thawed PMN adhering of frozen/thawed PMN to normal VEC and VEC injury increase, monoclonal antibody against LFA-1 could partly block PMN-VEC adhesion and attenuate VEC injury.</p>