Relationship between spinal neuronal microRNA 212 and phosphorylation of CREB in a mouse model of bone cancer pain / 中华麻醉学杂志

ABSTRACT

Objective To investigate the relationship between spinal neuronal microRNA 212 (miR-212) and phosphorylation of cAMP response element-binding protein (CREB) in a mouse model of bone cancer pain (BCP).Methods Thirty-two male SPF C3H/HeJ mice, aged 4-6 weeks, weighing 20-25 g, were randomly divided into 4 groups (n=8 each) using a random number table sham operation group (group S), BCP group, BCP + intrathecal negative control locked nucleic acid (LNA) group (group BC) , and BCP + intrathecal miR-212 antisense LNA group (group BL).After the mice were anesthetized with intraperitoneal pentobarbital sodium, 20 μl of α minimal essential medium containing NCTC 2472 cells 2×105 was injected directly into the medullary cavity of the distal femur.In BC and BL groups, negative control LNA and miR-212 antisense LNA 12 pmol/5 μl were intrathecally injected, respectively, once a day for 7 consecutive days, starting from day 14 after inoculation.In S and BCP groups, the equal volume of DNAse/RNAse-free water was given instead.The number of spontaneous flinches (NSF) and mechanical paw withdrawal threshold (MWT) were measured on 1 day before inoculation and 4, 7, 10, 14 and 21 days after inoculation.The mice of each group were sacrificed after measurement of pain threshold on 21 days after inoculation, and the lumbar enlargement segments of the spinal cord were harvested to detect the expression of phosphorylated CREB (p-CREB) and CREB using Western blot.Results Compared with group S, the MWT was significantly decreased, and the NSF was increased on 7-21 days after inoculation, and the expression of p-CREB was up-regulated in BCP, BC and BL groups.Compared with group BCP, the MWT was significantly increased, and the NSF was decreased on 21 days after inoculation, and the expression of p-CREB was down-regulated in group BL, and no significant change was found in the parameters mentioned above in BC group.There was no significant difference in the expression of CREB between the four groups.Conclusion Spinal neuronal miR-212 is involved in the maintenance of BCP probably by promoting phosphorylation of CREB in mice.