The Effect of Splenectomy on Hemoglobin levels in Rats

Background: The spleen filters aged and damaged red blood cells and supports immune function; however, it is often regarded as a vestigial organ. Splenectomy (SPX) is associated with excellent outcomes in the near-term, yet long-term studies show patients are more susceptible to bacterial infections and have an increased risk for cardiovascular disease and mortality. While it is known that the spleen regulates red blood cell turn over, there are few studies that look at the short- and long-term impact on hemoglobin (Hb) levels. Objective: Understand how splenectomy affects red blood cell (RBC) hemoglobin levels over long term. Hypothesis: Splenectomy will lead to reduced hemoglobin levels over time. Methods: All animal procedures were approved by the University of Guelph ACC. 24 male and female Wistar rats received SPX, and 12 male and female rats received the sham surgery. Whole blood was collected before surgery and at 16 weeks post SPX or sham under isoflurane. To assess RBC levels, Hb concentration was measured using the Hemocue Hb 201+ (HemoCue AB, Sweden). Results: At 8 weeks of age before surgery, males had a ~10% higher Hb than females. Sham surgery was associated with a ~10% increase in Hb concentration between 8 and 16 weeks of age, where males were consistently ~6% higher than females at this time point. In contrast, no increase in Hb concentration was observed with splenectomy within the same time frame. Conclusions: Interestingly, SPX was associated with a blunting of age-related increases in Hb levels. Whether this is related to a change in RBC levels or a change in Hb within the RBC remains to be determined. Regardless, this work suggests that the spleen plays a critical role in mediating age-related changes in Hb homeostasis and further work is needed to establish to understand the role of the spleen on Hb and RBCs. NSERC and CIHR This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.