Abstract: Objective To establish a rat model of bone metastasis pain induced by Walker 256 mammary gland carcinoma cells and observe the effect of dexamethasone on bone cancer pain. Methods Ascitic tumour cells were made from Walker 256 mammary gland carcinoma cells injected to tibia of rats.Then,the withdrawal threshold to mechanical stimulus and withdrawal time in response to radiant thermal stimulus were tested before and after operation.Results The withdrawal threshold to mechanical stimulus and withdrawal time in response to radiant thermal stimulus were significantly reduced in the tibia bone inoculated with Walker 256 cells.The pathology results showed the evidence of tibia bone structure was destructed by tumor.It is suggested that the model of bone metastasis pain induced by Walker 256 mammary gland carcinoma cell was successfully established.Dexamethasone (5 mg/kg ) elevated withdrawal threshold to mechanical stimulus in rat model of bone metastasis pain induced by Walker 256 mammary gland carcinoma cell.Conclusion Dexamethasone could alleviate bone cancer pain.

Key words: neoplasms, dexamethasone, pain measurement