沉默信息调节因子2在瑞芬太尼诱发的大鼠切口痛觉过敏中的作用及其机制研究

摘要 目的：探讨沉默信息调节因子2（Sirt2）在瑞芬太尼诱发的大鼠切口痛觉过敏中的作用及其机制。方法：18只SD大鼠采用随机数字表法分为I组（切口组，n=6），RI组（瑞芬太尼+切口组，n=6）和RI+Sirt2过表达组（瑞芬太尼+切口+Sirt2过表达组，n=6）。I组在大鼠足底制作切口痛模型的同时在腹部注射等容量生理盐水30 min，RI组和RI+Sirt2过表达组在足底进行切口痛模型制作的同时并泵注瑞芬太尼30 min，RI+Sirt2过表达组在脊髓水平提前1周注射Sirt2过表达慢病毒处理。各组大鼠分别于泵注瑞芬太尼或生理盐水术前24 h，泵注结束后2 h、6 h、24 h和48 h测定机械刺激缩足反应阈值（MWT）及热缩足潜伏期（TWL）。行为学测试结束后处死大鼠，取L_3-5脊髓节段，采用蛋白免疫印迹（Western blot）法检测Sirt2表达，超氧化物歧化酶2（SOD2）活性采用酶联免疫吸附法（ELISA）法测定，超氧阴离子水平和NADPH氧化酶活性采用化学发光法测定。结果：各组大鼠MWT和TWL的时间效应（F=683.602，624.033，均P<0.001）和组别×时间交互效应显著（F=9.142，4.550，均P<0.001），说明MWT和TWL有随时间变化的趋势并且时间因素的作用有随组别的不同而不同，组间比较差异有统计学意义（F=93.157，25.176，均P<0.001）。与I组比较，RI组T_1-4时MWT降低，TWL缩短（P<0.05）；RI+Sirt2过表达组T₂、T₄时间点MWT降低，T_2-4时间点TWL缩短（P<0.05）。与RI组比较，RI+Sirt2过表达组T_3-4时间点MWT升高，T_2-4时间点TWL延长（P<0.05）。三组大鼠Sirt2蛋白表达比较差异有统计学意义（F=265.643，P<0.001）；与I组比较，RI组和RI+Sirt2过表达组术后48 h脊髓组织Sirt2表达水平减少（P<0.05）；与RI组比较，RI+Sirt2过表达组术后48 h脊髓组织Sirt2表达水平增加（P<0.05）。三组大鼠脊髓组织SOD2活性、NADPH氧化酶活性、超氧化物阴离子表达比较差异有统计学意义（F=13.543，14.813，19.675，均P<0.001）；与I组比较，RI组和RI+Sirt2过表达组术后48 h脊髓组织SOD2活性水平降低，NADPH氧化酶活性和超氧化物阴离子水平增加（P<0.05）；与RI组比较，RI+Sirt2过表达组术后48 h脊髓组织SOD2活性水平增加，NADPH氧化酶活性和超氧化物阴离子减低（P<0.05）。结论：Sirt2通过调节氧化应激水平参与瑞芬太尼诱发切口痛大鼠痛觉过敏过程。

Role and Mechanism of Silent Information Regulator2 in Remifentanil-Induced Incisional Hyperalgesia in Rats

ABSTRACT Objective: To investigate the role and mechanism of silent information regulator 2 (Sirt2) in remifentanil-induced incisional hyperalgesia in rats. Methods: 18 SD rats were randomly divided into group I (incision group, n=6), RI group (remifentanil+incision group,n=6) and RI+Sirt2 overexpression group (remifentanil+incision+Sirt2 overexpression group, n=6). In I group, the incisional pain model was made in the plantar of the rat, and the equal volume of normal saline was injected in the abdomen for 30 min.The RI group and the RI+Sirt2 overexpression group were injected with remifentanil for 30 min while the incisional pain model was made in the plantar of the foot. The RI+Sirt2 overexpression group was injected with Sirt2 overexpression lentivirus 1 week in advance at the spinal cord level. The mechanical withdrawal threshold (MWT) and thermal withdrawal latency (TWL) were measured at 24 h before remifentanil or normal saline infusion and 2 h, 6 h, 24 h and 48 h after the end of remifentanil or normal saline infusion. The rats were sacrificed after the behavior test and the L_3-5 spinal cord segments were taken. The expression of Sirt2 was detected by Western blot. The activity of superoxide dismutase 2(SOD2) was determined by enzyme-linked immunosorbent assay (ELISA). The superoxide anion level and NADPH oxidase activity were determined by chemiluminescence. Results: The time effect (F=683.602, 624.033, all P<0.001) and group×time interaction effect (F=9.142, 4.550, all P<0.001) of MWT and TWL in each group were significant, indicating that MWT and TWL had a tendency to change with time and the effect of time factor was different with different groups, and the difference between groups was statistically significant (F=93.157, 25.176, all P<0.001). Compared with group I, MWT decreased and TWL shortened at T_1-4 in group RI(P<0.05). In RI + Sirt2 overexpression group, MWT was decreased at T₂ and T₄ time points, and TWL was shortened at T_2-4 time points(P<0.05). Compared with RI group, RI + Sirt2 overexpression group had higher MWT at T_3-4 time point and longer TWL at T_2-4 time point(P<0.05). There was significant difference in the expression of Sirt2 protein among the three groups (F=265.643, P<0.001). Compared with group I, the expression level of Sirt2 in spinal cord tissue of RI group and RI+Sirt2 overexpression group decreased at 48 h after operation (P<0.05). Compared with RI group, the expression level of Sirt2 in spinal cord tissue of RI+Sirt2 overexpression group increased at 48 h after operation(P<0.05). There were significant differences in SOD2 activity, NADPH oxidase activity and superoxide anion expression in spinal cord tissue among the three groups (F=13.543, 14.813, 19.675, all P<0.001). Compared with group I, the activity of SOD2 in spinal cord tissue of RI group and RI+Sirt2 overexpression group decreased at 48 h after operation, while the activity of NADPH oxidase and the level of superoxide anion increased(P<0.05). Compared with RI group, the activity of SOD2 in spinal cord tissue of RI+Sirt2 overexpression group increased at 48 h after operation, and the activity of NADPH oxidase and superoxide anion decreased (P<0.05). Conclusion: Sirt2 is involved in remifentanil-induced hyperalgesia in rats with incisional pain by regulating oxidative stress.