Underlying mechanism of chemokine receptor CCR2 antagonist in the treatment of bone cancer pain / 中国药理学通报

ABSTRACT

Aim To investigate the effect of intrathecal injection of CCR2 antagonist on pain behaviours,spinal astrocytes activation in the spinal cord in a rat model of bone cancer pain. Methods Forty female SD rats weighing 150 ~180 g were randomly divided into five groups ( n=8 each )(Ⅰ) sham group;(Ⅱ) sham +RS102895 group;(Ⅲ) bone cancer pain group;(Ⅳ) bone cancer pain + DMSO group;(Ⅴ) bone cancer pain+RS102895 group. Rats received i. t. injections of either RS102895 (3 g·L-1 ) 10 μl or 10%DMSO 10 μl at the time of 10-12 days after the operation. Bone cancer was induced by intra-tibial inoculation of 1 × 105 Walker 256 breast cancer cell. Mechanical hind paw withdrawal threshold test was performed one day before and at 3rd,6th,9th, 10th,11th and 12th days after surgery. Immunofluorescence was used to observe the activation of the spinal astrocytes. Results Compared with group Ⅰ, the rats in bone cancer pain group appeared obvious mechanical hyperalgesia (Ⅲ、Ⅳ、Ⅴ) ,the volume,shape and mean optical den-sity ( MOD) of spinal astrocytes could be seen obvious-ly increased,groupⅡhad no obvious statistical signifi-cance (P>0. 05). Compared with group Ⅳ ,i. t. in-jections of RS102895 increased the paw mechanical withdrawal threshold, suppressed the action of astro-cytes,reduced the MOD of spinal astrocytes. Conclu-sion CCR2 might participate in the formation of bone cancer pain via activating spinal astrocytes. CCR2 will be a potential target for the treatment of bone cancer pain.