Changes in acetylation of histone in spinal dorsal horn in a rat model of persistent postoperative pain / 中华麻醉学杂志

ABSTRACT

Objective To investigate the changes in acetylation of histone in the spinal dorsal horn in a rat model of persistent postoperative pain.Methods Ninety-six malc Sprague-Dawley rats,weighing 200-250 g,aged 6-8 weeks,were randomly divided into 2 groups (n=48 each) using a random number tablesham operation group (group S) and persistent postoperative pain group (group PPP).The rat model of persistent postoperative pain evoked by skin/muscle incision and retraction was established according to the method described by Flatters.After the rats were anesthetized with intraperitoneal chloral hydrate,the skin and superficial muscle of the medial thigh were incised and retractors inserted.This tissue was retracted for 1 h.The mechanical paw withdrawal threshold (MWT) was measured at 1 day before operation and 1,3,7,14,and 21 days after operation.Four animals were sacrificed in each group after measurement of MWT at each time point for detection of acetylated histone H3 (Ac-H3) and acetylated histone H4 (Ac-H4) expression (by Western blot analysis) and the number of Ac-H3 and Ac-H4 positive cells in the spinal cord horn (by immunofluorescence histochemistry).Results Compared with group S,the MWT was significantly decreased at 3,7,14 and 21 days after operation,the expression of Ac-H3 and Ac-H4b was significantly down-regulated at 3,7 and 14 days after operation,and the number of Ac-H3 and Ac-H4 positive cells was significantly decreased at 7,14 and 21 days after operation in group PPP (P＜0.05 or 0.01).The MWT,expression of Ac-H3 and Ac-H4b,and the number of Ac-H3 and Ac-H4 positive cells were significantly higher at 21 days after operation than at 14 days after operation in group PPP (P＜0.05).Conclusion Acetylation of histone in the spinal dorsal horn is decreased after operation,which may be involved in the development and maintenance of persistent postoperative pain in rats.