Role of spinal histone acetylation in persistent postoperative pain in rats / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the role of spinal histone acetylation in persistent postoperative pain in rats. Methods Pathogen?free healthy male Sprague?Dawley rats, weighing 200-250 g, aged 2 months, in which intrathecal catheters were implanted at the lumbar level according to an improved method, were used in the study. Eighty?four rats, in which intrathecal catheters were successfully implanted, were divided intoⅠ-Ⅵgroups(n=14 each)using a random number table. Artificial cerebrospinal fluid 20 μl was intrathecally administered at 1, 2, 3 and 4 days before operation and 1 day after operation inⅠandⅣgroups. At 1, 2, 3 and 4 days before operation and 1 day after operation, dimethyl sulfoxide 10 μl and SAHA(50 μg∕10μl)were intrathecally injected inⅡandⅤgroups and inⅢandⅥgroups, respective?ly, followed by artificial cerebrospinal fluid(10 μl)flush after each injection. Rats underwent sham oper?ation inⅠ?Ⅲ groups. Persistent postoperative pain was evoked by skin∕muscle incision and traction in Ⅳ?Ⅵ groups. The mechanical paw withdrawal threshold(MWT)was measured at 1 day before operation(T0)and 1, 3, 7, 14 and 21 days after operation(T1?5). Four rats were sacrificed in each group after measurement of MWT at T4, and the lumbar segments(L4?6)of the spinal cord were removed for determi?nation of the expression of acetylated histone H3(Ac?H3)and Ac?H4 by Western blot. Results There was no significant difference in each index amongⅠ?Ⅲ groups(P>0.05). Compared with group Ⅰ, the MWT was significantly decreased at T2?5, and the expression of Ac?H3 and Ac?H4 was down?regulated at T4 in group Ⅳ(P<0.05). Compared with group Ⅳ, the MWT was significantly increased at T2?5, and the expression of Ac?H3 and Ac?H4 was up?regulated at T4in group Ⅵ(P<0.05). Conclusion Histone acetylation is involved in the development and maintenance of persistent postoperative pain in rats.