AIMTo investigate the mechanism of the vascular endothelial cell (VEC) injury caused by freezing/thawing.

METHODSThe frozen/thawed neutrophil (PMN) model was founded by freezing PMNs with a rate cooling instrument and then rewarming them in a water bath, the PMNs used here were separated from rat's peripheral blood using density gradients centrifugation techniques. The expression of LFA-1 on the surface of frozen/thawed PMNs was observed at 4 h,12 h and 24 h after freezing/thawing. After co-incubating untreated VECs with frozen/thawed PMNs, we detected the VEC injury and the changes in PMN-VEC adhesion.

RESULTS(1) The PMNs LFA-1 expression increased in a time-dependent manner within 24 h after the freezing/thawing of PMNs. (2) After co-incubating untreated VECs with frozen/thawed PMNs, the adhesion between frozen/thawed PMNs and VECs increased and VEC injury occurred. (3) Monoclonal antibody against LFA-1 could block the PMN-VEC adhesion and subsequently attenuated the VEC injury.

CONCLUSIONThe freezing/thawing of PMNs can elicited an increase in PMN LFA-1 expression and trigger the PMN-VEC adhesion and subsequently bring about the VEC injury.