阿米替林对神经病理性痛大鼠杏仁体外侧核HDAC5磷酸化的影响

Effect of amitriptyline on phosphorylation of HDAC5 in basolateral amygdale of rats with neuropathic pain

目的评价阿米替林对神经病理性痛大鼠杏仁体外侧核组蛋白去乙酰化酶5(HDAC5)磷酸化的影响。方法健康雄性Wistar大鼠30只,体重250~300 g,采用随机数字表法分为3组(n=10):假手术组(S组)、神经病理性痛组(NP组)和阿米替林组(A组)。采用坐骨神经分支选择性损伤法建立大鼠神经病理性痛模型。A组于造模后第14~35天时,每天腹腔注射阿米替林10 mg/kg,S组和NP组每天腹腔注射等容量生理盐水。分别于造模后第3、7、14、21、28和35天时测定机械缩足反应阈(MWT)。造模后第36天时,行强迫游泳实验,记录大鼠不动时间、攀爬时间和游泳时间。随后处死大鼠,取杏仁体外侧核脑组织,Western blot法检测杏仁体外侧核HDAC5和磷酸化HDAC5(p-HDAC5)的表达水平,采用实时定量PCR法检测杏仁体外侧核HDAC5 mRNA的表达水平。结果与S组比较,NP组各时点MWT降低,不动时间延长,游泳时间和攀爬时间缩短,A组造模后第14、21和28天时MWT降低,杏仁体外侧核p-HDAC5表达下调,HDAC5 mRNA表达上调(P<0.05);与NP组比较,A组造模后第21、28和35天时MWT升高,不动时间缩短,攀爬时间延长,杏仁体外侧核p-HDAC5表达上调,HDAC5 mRNA表达下调(P<0.05或0.01)。结论阿米替林改善神经病理性痛大鼠抑郁的机制与促进杏仁体外侧核HDAC5的磷酸化水平有关。

Objective To evaluate the effect of amitriptyline on the phosphorylation of histone deacetylase 5(HDAC5)in the basolateral amygdala(BLA)of rats with neuropathic pain.Methods Thirty healthy male Wistar rats,weighing 250-300 g,were divided into 3 groups(n=10 each)using a random number table method:sham operation group(S group),neuropathic pain group(NP group)and amitriptyline group(A group).Spared nerve injury was produced by exposing the sciatic nerve and its branches and ligation and transection of tibial nerve and common fibular nerve in anesthetized rats.Amitriptyline 10 mg/kg was intraperitoneally injected every day on 14-35 days after establishing the model in group A,while the equal volume of normal saline was given instead of amitriptyline in S and NP groups.The mechanical paw withdrawal threshold(MWT)was measured on 3,7,14,21,28 and 35 days after establishing the model in each group.The forced swimming test was performed on day 36 after establishing the model,and immobility time,climbing time and swimming time were recorded.The rats were then sacrificed,and brain tissues in BLA were obtained for determination of the expression of HDAC5 and phosphorylated HDAC5(p-HDAC5)(by Western blot)and expression of HDAC5 mRNA(by real-time quantitative polymerase chain reaction).Results Compared with group S,the MWT was significantly decreased at each time point,the immobility time was prolonged,and the swimming time and climbing time were shortened in group NP,and the MWT was significantly decreased on days 14,21 and 28 after establishing the model,the expression of p-HDAC5 was down-regulated,and the expression of HDAC5 mRNA was up-regulated in group A(P<0.05).Compared with group NP,the MWT was significantly increased on days 21,28 and 35 after establishing the model,the immobility time was shortened,the climbing time was prolonged,the expression of p-HDAC5 was up-regulated,and the expression of HDAC5 mRNA was down-regulated in group A(P<0.05 or 0.01).Conclusion The mechanism by which amitriptyline improves depression is associated with promoting the phosphorylation of HDAC5 in BLA of rats with NP.