The influence of single or repeated phlebotomy on the physiological condition of normal and diseased rats

The present experiment was performed to see the influence of phlebotomy on hematology, serum chemistry, and pathology data in rats. When normal rats received a single phlebotomy of 2 or 3 ml blood, erythrocyte count and hematocrit were slightly reduced along with a persistent depression of the blood pressure. In repeated phlebotomy studies, 0.25 to 2 ml each of blood was removed from each rat every other day for 10 days. Normal rats from which 0.5 ml and more of blood was withdrawn showed decreases in erythrocyte count and serum iron level concomitant with an increase in reticulocyte count. Similar findings were obtained in rats with CCl4 liver damage or gentamicin nephrotoxicity, except that those rats hardly exhibited anemia because of a simultaneous occurrence of hemoconcentration. Histopathological findings of the liver and kidney were not different between animals with and without phlebotomy. In phenylhydrazine-treated rats receiving repeated phlebotomy, one rat in the 1-ml phlebotomy and two rats in the 2-ml phlebotomy died from severe anemia. Surviving rats receiving 2-ml phlebotomy showed higher serum GOT and GPT activities together with fatty deposition and/or focal necrosis of hepatocytes. It is concluded that every-other-day phlebotomy of up to 0.25 ml each does not significantly influence the physiological condition of normal or diseased rats.