[Establishment and evaluation of a bone cancer pain model]

To explore the feasibility of a bone cancer pain model by injecting the Lewis lung carcinoma cells into the femur bone marrow cavity of C57BL/6 mice.

Sixty clear grade male C57BL/6 mice (body weight 18 approximately 20 g) were randomly divided into 4 groups(15 in each group). Cancer cell inoculated group: 2*10(6) Lewis lung carcinoma cells in 10 microL PBS were injected into the left femur bone marrow cavity, and the other 3 control groups were injected the heat inactivated Lewis cells, PBS, or a false operation respectively. Spontaneous lifting time and mechanical allodynia threshold of the mice hind paw were measured in the alternative days throughout the experiment. The structural damage of the femur was monitored by radiogram on the 7th,15th, and 23rd day respectively,and the pathohistological changes of the femur bones were observed by HE staining on the same days.

Those mice that received intra-femur innoculation of Lewis lung carcinoma cells gradually developed the spontaneous pain, which was began on the 11th day after the innoculation, and followed by mechanical allodynia. The course of flinch lasted in the later experimental session. The 50% Von Frey threshold was significantly decreased on the 13th day after the innoculation, and the mechanical allodynia lasted the whole experimental period. On the 23rd day after the innoculation, X-ray film showed that the medullary cavity of ipsilateral distal femur was filled with tumor cells, and the cortical bone became thick; furthermore, the tumor cells invaded the peripheral muscles.

Injecting the Lewis lung carcinoma cells into the femoral medullary cavity of C57BL/6 mice can successfully establish a murine bone cancer pain model, and the murine model shows much resemblance compared with the human bone cancer pain.