OBJECTIVETo explore the occurrence and various influencing factors of the splenic extramedullary hematopoiesis in rats.

METHODSA total of 411 rats of different sex and species were assigned to this study. These rats were fed different feed in the same environment, and killed after 104 weeks. The spleen of all animals was embedded in paraffin, sectioned, stained with hematoxylin and eosin(H& E), then examined by optical microscopy to observe splenic extramedullary hematopoiesis.

RESULTSAt the end of the study, it was found that the splenic extramedullary hematopoiesis occurred in 116 animals (28.22%). The splenic extramedullary hematopoiesis that included the erythroid, granulocytic and megakaryocytic lineages (23.11%); the inciderce of splenic extramedullary hematopoiesis in Wistar rats was higher than that in SD rats; the incidence of splenic extramedullary hematopoiesis in female was higher than that in male; the feed had no effect on splenic extramedullary hematopoiesis of all animals; different species and different feed were also did not involve in the level of splenic extramedullary hematopoiesis.

CONCLUSIONSpecies and sex show effect on the incidence of splenic extramedullary hematopoiesis, but does not involve in the level of splenic extramedullary hematopoiesis; feed had no influences on all indexes of splenic extramedullary hematopoiesis. The results of this study may provide a reference for the study of the splenic extramedullary hematopoiesis of the aging human.