Role of chemokine ligand 2 in spinal eord in a rat model of tibia bone cancer pain / 中华麻醉学杂志

ABSTRACT

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.