The effect of splenectomy on blood cell levels during hibernation and the circulation of chilled platelets in thirteen-lined ground squirrels (Ictidomyces tridecemlineatus)

Abstract

Hibernation leads to major changes in physiology, including drastic reductions in circulating leukocytes, thrombocytes, and clotting factors in the blood of many animals. We use the thirteen-lined ground squirrels (Ictidomys tridecemlineatus), a hibernating mammal, to better understand the impact of these changes on blood parameters, and in this case on platelets and leukocytes. The knowledge gained from this study may have direct importance in platelet transfusion medicine. To determine the role of the spleen in the sequestration of blood cells during hibernation, we compared platelet and white blood cell counts from splenectomized and sham-operated animals. Results showed that splenectomy had little effect on the circulating levels of neutrophils, lymphocytes, or monocytes during hibernation, but high variability and small sample size may have limited findings of significance. In addition, we followed the in vivo clearance rate of platelets stored at 3 7?C and 4 oc in ground squirrels to determine whether chilled ground squirrel platelets were resistant to the rapid clearance that is observed when chilled human platelets are injected into humans. We found that regardless of incubation temperature, ground squirrel platelets were cleared from circulation at the same rate. This rate was very similar to the clearance rate of warm-incubated rat platelets (Melin 2009). Identification of protective factors that prevent rapid clearance of chilled platelets may ultimately lead to the ability to refrigerate and better preserve human platelet concentrates.