OBJECTIVETo establish a model of human monocytic leukemia with CNS infiltration in BALB/c nude mice.

METHODSBALB/c nu/nu mice pre-treated by splenectomy, cytoxan intraperitoneal injection, and sublethal irradiation (SCI), were transplanted intravenously with 1 x 10(7) of human monocytic leukemic SHI-1 cells. The leukemic cells engrafted in the mice were detected by RT-PCR, histopathological examination, immunohistochemistry and FCM.

RESULTSThe survival time of SCI-nu/nu mice was 33-46 d. Paraplegia occurred in some of the mice. 5 weeks after transplantation, SHI-1 cells engrafted in SCI-nu/nu mice, multi-organs were involved and green solid neoplasms were formed in some organs. Histopathological examination found that SHI-1 cells infiltrated in liver, lung, kidney and testis of the mice and vertebral and skull bone marrow was replaced by leukemic cells. Leukemic cell penetrated through the surface of vertebrae, formed neoplasm, and entered the subdural space, but seldom involved the spinal parenchyma. In brain leukemia cells were filled in the subdural space and pia-arachnoid, covered the surface of cerebrum, cerebellum, spread along the virchow-robin space on the surface of pia mater, and eventually invaded the brain parenchyma.

CONCLUSIONSHI-1 cells could engrafted in the SCI-nu/nu mice, form an efficient and reproducible experimental model of CNSL and systematic leukemia. This model may be useful for studying the pathogenesis of CNSL.