Résumé
Objective To evaluate the changes in the expression of spinal endothelin-1 (ET-1) and its receptors in a mouse model of bone cancer pain (BCP).Methods Ninety-six healthy male SPF C3H/HeN mice,aged 4-6 weeks,weighing 20-25 g,were divided into 2 groups (n=48 each) using a random number table:sham operation group (group S) and BCP group.BCP was produced by injecting α-MEM 20 μl containing 1×104 cells/μ1 NCTC 2472 osteosarcoma cells into the distal medullary cavity of the right femur bone.In group S,t-MEM 20 μl was injected into the distal medullary cavity of the right femur bone.Mechanical paw withdrawal threshold (MWT) and the number of spontaneous flinches (NSF) were measured on 1 day before inoculation (T0) and 4,7,10,14 and 21 days after inoculation (T1-5).Twelve mice of each group were randomly sacrificed at T0,2,4,5,and the lumbar enlargement segments of the spinal cord were harvested to detect the expression of ET-1,endothelin type A receptor and endothelin type B receptor protein and mRNA (using Western blot or real-time polymerase chain reaction).Results The MWT was significantly lower and the NSF was higher at T1 in group S and at T1-5 in group BCP than at T0 (P＜0.05).Compared with group S,the MWT was significantly decreased and the NSF was increased at T2-s,and the expression of ET-1,endothelin type A receptor and endothelin type B receptor protein and mRNA was down-regulated at T2,4,5 in group BCP (P＜0.05).Conclusion The pathophysiological process of BCP is associated with down-regulating the expression of spinal ET-1 and its receptors in mice.