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Evaluation of the Erythroid Regenerative Response in Two Different Models of Experimentally Induced Iron Deficiency Anemia
Author(s) -
Burkhard Mary Jo,
Brown Diane E.,
McGrath John P.,
Meador Vince P.,
Mayle Douglas A.,
Keaton M. Joni,
Hoffman Wherly P.,
Zimmermann John L.,
Abbott David L.,
Sun Steven C.
Publication year - 2001
Publication title -
veterinary clinical pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.537
H-Index - 51
eISSN - 1939-165X
pISSN - 0275-6382
DOI - 10.1111/j.1939-165x.2001.tb00262.x
Subject(s) - phlebotomy , reticulocytosis , microcytosis , hemoglobin , weanling , erythropoiesis , reticulocyte , medicine , anemia , endocrinology , microgram , bone marrow , iron deficiency , hemolysis , hematocrit , immunology , chemistry , biochemistry , in vitro , messenger rna , gene
Anemia was induced in weanling Sprague Dawley rats either by feeding an iron‐deficient diet or by chronic phlebotomy. The erythroid regenerative response was then evaluated before and after a hemolytic event, and results were compared with those of a third group of control nonphlebotomized rats fed an iron‐replete diet. Diet and phlebotomy groups developed a similar degree of anemia (mean hemoglobin concentration 7.9 g/dL and 7.8 g/dL, respectively; controls, 13.9 g/dL) and hypoferremia (mean serum iron concentration 25.4 μg/dL and 34.9 μg/dL, respectively; controls, 222.0 μg/dL). However, the anemia in diet rats was nonregen‐erative (reticulocyte count, 83.1×10 3 cells/μL) and associated with bone marrow erythroid hypoplasia; whereas the anemia in phlebotomy rats was regenerative (reticulocyte count, 169.6×10 3 cells/μL) and associated with bone marrow erythroid hyperplasia. Thrombocytosis was seen in diet rats (l,580×10 3 cells/μL) but not phlebotomy rats (901×10 3 cells/μL) when compared with controls (809×10 3 cells/μL). To further evaluate the regenerative capability, phenylhydrazine (PHZ) was administered to induce hemolysis. Erythrocyte mass declined approximately 25% in all groups, including controls. The reticulocytosis (265.3×10 3 cells/μL) seen in phlebotomy rats was earlier and significantly greater than that seen in either diet or control rats. Hemoglobin concentration returned to pre‐PHZ concentrations (7.9 g/dL) in phlebotomy rats within 4 days posthemolysis. In diet rats, the maximal regenerative response (176.3×10 3 cells/μL) was not seen until 8 days posthemolysis, and hemoglobin (7.5 g/dL) did not return to pre‐PHZ concentrations during the 8‐day study. In many aspects, the anemia seen following diet‐or phlebotomy‐induced iron deficiency was similar. However, the erythroid regenerative capability varied depending on the mechanism by which anemia was induced and furthermore altered the efficiency of hemoglobin production following a hemolytic event. These results suggest that the availability of iron in the diet may modulate the pathogenesis of iron deficiency anemia.