Perioperative stress prolong post-surgical pain via miR-339-5p targeting in the amygdala.

BACKGROUND

The decreased expression of mu-opioid receptors (MOR) in the amygdala may be a key molecular in chronic post-surgical pain (CPSP). It is known that miR-339-5p expression in the amygdala of a stressed rat model was increased. Analyzed by RNAhybrid, miR-339-5p could target opioid receptor mu 1 () which codes MOR directly. So, the authors hypothesized that miR-339-5p could regulate the expression of MOR via targeting and cause the effects to CPSP.

METHODS

To simulate perioperative short-term stress, a perioperative stress prolongs incision-induced pain hypersensitivity without changing basal pain perception rat model was built. A pmiR-RB-REPORT™ dual luciferase assay was taken to verify whether miR-339-5p could act on as a target. The serum glucocorticoid level of rats was test. Differential expressions of MOR, GFAP, and pERK1/2 in each group of the rats' amygdala were tested, and the expressions of miR-339-5p in each group of rats' amygdalas were also measured.

RESULTS

Perioperative stress prolonged the recovery time of incision pain. The expression of MOR was down-regulated in the amygdala of rats in stress + incision (S + IN) group significantly compared with other groups ( < 0.050). miR-339-5p was up-regulated in the amygdala of rats in group S + IN significantly compared with other groups ( < 0.050). miR-339-5p acts on 3'UTR and take MOR mRNA as a target.

CONCLUSIONS

Perioperative stress could increase the expression of miR-339-5p, and miR-339-5p could cause the expression of MOR to decrease via targeting . This regulatory pathway maybe an important molecular mechanism of CPSP.