Inhibition of microglia activation affected the maintenance of cancer pain in a murine model / 中国药理学通报

ABSTRACT

Aim To investigate the effect of intrathecal injection(it) of minocycline(MC),a selective microglia inhibitor,on the maintenance of pain in a murine model of cancer pain.Methods Forty-two male C3H/He mice were randomly divided into 3 groups(n=14 each)sham+PBS group was operated and received 10 ?l PBS injection into calcaneus medullary space;sarcoma+PBS group and sarcoma+MC group were operated and received 2?105 sarcoma cells/10 ?l PBS implantation into calcaneus medullary space.On the PID11(post-implantation day 11),10 mice were taken from each group randomly,sarcoma+PBS group and sham+PBS group were received 0.9% NS(5 ?l) it sarcoma+MC group was received MC(1 nmol,5 ?l) it Mechanical pain threshold and cold hyperalgesia assay were measured before and after it at 0.5,1,2,4,8,24 h.The last 4 mice of each group were received a normally non-noxious palpation of the ipsilateral heel 90 min on the PID12 after it,then the animals were killed and L4-6 segment of spinal cord was removed for analysing the c-fos expression(by immunohistochemistry).Results Bone cancer pain decreased the mechanical and cold pain threshold and activated the c-fos expression in the spinal cord;MC it transient attenuated bone cancer pain-induced hyperalgesia and allodynia and suppressed the expression of c-fos protein.Conclusion The activation of microglia in the spinal cord may be involved in the maintenance of bone cancer pian.