脊髓趋化因子配体2在大鼠胫骨癌痛中的作用

目的 探讨脊髓趋化因子配体2(CCL2)在大鼠骨癌痛中的作用.方法 健康成年雌性SD大鼠84只,体重160～ 180g,采用随机数字表法,将其随机分为3组(n=28):正常对照组(C组)、假手术组(S组)和骨癌痛组(P组).P组胫骨骨髓腔内注射Walker-256乳腺癌细胞混悬液制备大鼠胫骨癌痛模型；S组胫骨骨髓腔内注射生理盐水；C组不作任何处理.于接种前ld、接种后l、3、7、10、14和21 d时,测定机械性刺激阈值.于接种前ld、接种后7、14和21'd时痛阈测定结束后,各组随机处死6只大鼠,取L4～6脊髓组织,采用ELISA法测定CCL2含量,反映其表达.接种后14 d时痛阈测定结束后,P组随机取4只大鼠,采用免疫荧光双标染色法观察脊髓背角CCL2与离子钙接头蛋白分子-1(小胶质细胞特异性标记物)、胶质纤维酸性蛋白(星形胶质细胞特异性标记物)和神经元特异核蛋白(神经元特异性标记物)的共表达情况.结果 与C组和S组相比,P组接种后7～21 d时机械性刺激痛阚下降,接种后7、14和21 d时脊髓CCL2表达上调(P＜0.05).骨癌痛大鼠脊髓背角CCL2在小胶质细胞和星形胶质细胞中存在表达,而在神经元中无表达.结论 脊髓小胶质细胞和星形胶质细胞中释放的CCL2参与了大鼠胫骨癌痛的发生发展.

Role of chemokine ligand 2 in spinal eord in a rat model of tibia bone cancer pain

Objective To investigate the role of chemokine ligand 2 (CCL2) in the spinal cord expression in a rat model of tibia bone cancer pain.Methods Eighty-four female SD rats weighing 160-180 g were randomly divided into 3 groups ( n =28):control group (group C),sham operation group (group S) and tibia bone cancer pain group (group P).Tibia bone cancer pain was induced by intra-tibial inoculation of Walker-256 breast cancer cells.Paw withdral threshold to mechanical stimulation (MWT) was measured with von Frey filaments at 1 d before and at 1,3,7,10,14 and 21 d after inoculation.Six rats in each group were sacrificed after the measurement of MWT at 1 d before inoculation and at 7,14 and 21 d after inoculation.Lumbar 4-6 segments of the spinal cord were removed for determination of the expression of CCL2 by ELISA.The coexpression of CCL2 with Iba-1 (a specific marker of microglia),GFAP(a specific marker of astrocyte) and NeuN (a specific marker of neuron) was determined by double immunofluorescence assay after the measurement of MWT at 14 d after inoculation in group P.Results Compared with groups C and S,MWT was significantly decreased from 7 d to 21 d after inoculation,the expressive of CCI-2 in the spinal cord up-regulated at 7,14 and 21 d after inoculation in group P ( P ＜ 0.05).CCL2 was expressed in the microglia and astrocyte but not in neuron in the spinal cord dorsal horn in a rat model of tibia bone cancer pain.Conclusion Release of CCL2 from microglia and astrocytes in the spinal cord was involved in mechanical hyperalgesia in a rat model of tibia bone cancer pain.