Effect of acute hypoxia and hypoxic acclimation on hemorheological behavior in rats with frostbite.

It was found that cold injury in rats acclimated to hypoxia was more serious than that in nonacclimated ones. In order to go further into the cause, blood rheological parameters in rats of frostbite at normoxia (FN), frostbite during acute hypoxia (FAH) and frostbite during hypoxia after hypoxic acclimation (FHAC) groups were observed before and after freezing. Before freezing, systemic hematocrit (Hct), blood viscosity, RBC aggregation index and RBC rigidity of FHAC group were higher and RBC deformability index (DI) of FHAC group was lower distinctly than those of FN and FAH groups. After frostbite, the aforesaid changes aggravated prominently, plasma viscosity of FHAC group reduced and was lower than that of FN and FAH groups. The results suggest that the hemorheological behavior is deteriorated in rats acclimated to hypoxia or subjected to freezing, and worsens in hypoxic acclimation rats after freezing. The changes in hemorheological behavior may be one of the causes that would make the frostbite damage more severe in rats acclimated to hypoxia.