Effect of cold acclimation on hemorheological behavior in rats with frostbite

The hemorheological behavior pre- and post-freezing and tissue survival area (TSA) of frostbitten hind feet in cold-acclimated rats (group CA) and the control (group C) were observed in order to go further into the mechanism of cold acclimation. The results indicated that blood viscosity and RBC aggregation tendency were lowered and RBC deformability improved obviously in CA rats as compared with those in group C (p<0.01). After the rats' hind feet were frozen, the hemorheological behavior in both group CA and C rats was changed abnormally and the changes were less serious in CA rats than those in C rats. The TSA of CA rats was much larger than that of C rats (p<0.01). The aforesaid results revealed that after rats were acclimated to cold, their resistance to freezing increased and their adaptive changes in hemorheological behavior occurred. The extent of abnormal changes in hemorheological behavior caused by freezing was reduced in CA rats, therefore the disorder microcirculation could be improved. These changes were beneficial to the frostbitten tissue to recovering and healing. So it is considered that in CA rats, the adaptive change in hemorheological behavior is one of the cause enhancing resistance to frostbite.