AIMTo investigate the role of ICAM-1 on the surface of vascular endothelial cell (VEC) in freezing/thawing injury of VEC, in order to elucidate the pathogenesis of freezing/thawing injury.

METHODSVEC separated and cultured from rat aorta and PMN separated from rat peripheral blood were selected as experiment materials. The frozen/thawed VEC model was founded by freezing VEC with the type WKL-V rate cooling instrument and then rewarming them in a water bath. ICAM-1 expression on the surface of frozen/thawed VEC was detected at 4, 12 and 24 h after freezing/thawing with immunohistochemical method. After coincubating frozen/thawed VEC with normal PMN, the adhesion of VEC to PMN was monitored with rose bengal staining assay and the injury level of VEC was indicated by measuring LDH activity in nutrient solution.

RESULTSThe ICAM-1 expression on the surface of VEC increased from 13.2% +/- 3.6% before freezing/thawing of VEC to 22.3% +/- 4.4% at 4 hour after freezing/thawing, and reached the peak (37.9% +/- 2.5%) at 12 hour after freezing/thawing of VEC. After coincubation of frozen/thawed VEC with normal PMN, the adherence of frozen/thawed VEC to PMN increased from group control 0.204 +/- 0.025 to 0.363 +/- 0.022 (P < 0.01), LDH activity in nutrient solution increased from group control 104.64 +/- 20.14 U/L to 162.33 +/- 27.88 U/L (P < 0.01), monoclonal antibody against ICAM-1 (ICAM-1 Mab) could partially block the adherence of frozen/thawed VEC to PMN (0.270 +/- 0.021, P < 0.01), and diminish LDH activity in nutrient solution (125.39 +/- 22.26 U/L, P < 0.05).

CONCLUSIONThe freezing/thawing of VEC can elicit an increase in ICAM-1 expression on the surface of VEC, and then proceed to VEC-PMN adherence and lead to VEC injury.