Histopathology of nude mice induced by granulocyte-macrophage colony-stimulating factor

Significant elevation in the peripheral granulocyte count (more than 20,000) and the absence of overt infection are commonly associated with a wide variety of human neoplasms. Robinson demonstrated a dose correlation between the amount of the serum and urine levels of granulocyte-macrophage colony stimulating factor (GM-CSF) and the peripheral neutrophil counts. In vivo assessment of hematopoietic activities induced by GM-CSF has not been explored owing to the complexity, time consuming, and ill-defined specific results. This experiment is designed to understand the pathophysiology of the hematopoiesis induced by GM-CSF released from tumor of Chinese Hamster Ovary (CHO) cell line in nude mice. To our knowledge, this experiment is the first one to describe detailed histopathological changes induced by GM-CSF. Three to five months old nude mice inoculated subcutaneously with the CHO cell line developed local tumor with or without metastasis and hepatosplenomegaly. Active granulopoiesis is demonstrated in bone marrow, spleen, liver, and some of the tumors. Lymph nodes show histiocytic proliferation, however, without active granulopoiesis. Peripheral granulocytosis seems to be not linearly but step-wisely coordinated with tumor growth.