Bone cancer pain induce anxiety-like behavior and high expression of NR2B subunit in anterior cingulate cortex of rats / 临床麻醉学杂志

ABSTRACT

Objective To investigate the effect of bone cancer pain on emotion and NMDA re-ceptor NR2B subunit expression level in anterior cingulate cortex (ACC)in rats.Methods One hun-dred and fifty healthy male Wistar rats weighing 200-250 g aged 3 months old were randomly divided into 3 groups (n = 50 in each group)sham operation group (group S),bone cancer pain group (group BCP),RO25-6981 group (group RO).The BCP model was established by inoculating Walker 256 breast cancer cells into right intra-tibial.Rats in group S were given the same dose of d-hanks. Group RO was injected intraperitoneally with RO25-6981 (5 mg/kg/d)on the day of inoculation, while rats in the group S and group BCP were given the same dose of normal saline.Mechanical with-drawal threshold (MWT)and thermal withdrawal latency (TWL)of right hind legs were measured on day 7,10,14 after inoculation respectively.Elevated plus-maze test was carried out to investigate the effect of bone cancer pain on emotion in rats after pain threshold detection,then the percentage of the times entering the open arms (OE)and the percentage of the time staying in the open arms (OT) duration the total period were evaluated.Then the anterior cingulate cortex tissue was removed to e-valuate the NR2B protein and mRNA expression levels by RT-PCR,Western blot and immunofluo-rescence methods on day 14 after elevated plus-maze test.Results All the parameters did not differ with significant difference between group S and group RO.MWT decreased and TWL shortened on day 7,10,14 after inoculation in group BCP compared with those before inoculation and those of group S and group RO.OE and OT in group BCP reduced remarkably than those before inoculation and those of group S and group RO.Relative absorbance of NR2B mRNA,the expression of NR2B pro-tein,average NR2B relative fluorescence intensity value is obviously higher than that of group S and group RO (P <0.05).Conclusion Bone cancer pain can induce pain-related aversion and anxiety-like behavior of rats,and the mechanism may be related to the high expression of NR2B in anterior cingu-late cortex.