吗啡对神经病理性疼痛大鼠脊髓背角PSD-95表达的影响

Effect of morphine on the expression of PSD-95 in the spinal dorsal horn of rats with neuropathic pain

目的观察吗啡对神经病理性疼痛大鼠脊髓背角突触后致密物质95(PSD-95)蛋白表达水平的影响。方法将健康雄性Wistar大鼠随机分为假手术组(SO组)、神经病理性疼痛组(NP组)和吗啡组(NP+Mor组),每组6只。采用坐骨神经分支保留性损伤(SNI)的方法制备神经病理性疼痛模型,吗啡组大鼠在处死前2h注射吗啡(15mg/kg)。术前、术后第3、7、14天、吗啡用药后30min测各组大鼠右后足机械痛阈,计算50%缩足阈值。术后14d吗啡用药2h后,处死大鼠,用Western Blotting法检测脊髓背角PSD95的蛋白表达水平。结果与SO组比较,NP组50%PWT降低,PSD95的蛋白表达水平升高;与NP组比较,Mor组50%PWT升高,PSD95的蛋白表达水平降低。结论吗啡急性用药可减轻神经病理性疼痛大鼠的脊髓背角区PSD95蛋白表达增多。

Objective To study the effect of morphine on the expression level of postsynaptic density protein 95(PSD-95)in spinal dorsal horn of rats with neuropathic pain.Methods Healthy male Wistar rats were randomly divided into three groups:sham operation group(SO group),neuropathic pain group(NP group)and morphine group(NP+Mor group),with 6 rats in each group.The neuropathic pain model was prepared by the method of spared nerve injury(SNI).Rats in morphine group were injected with morphine 2h before execution.The mechanical pain threshold of the right hind paw of each group was measured respectively before surgery and 3,7,14 days after surgery,and 30 minutes after morphine injection.The 50%paw withdrawal threshold(50%PWT)was calculated.On the 14th day after surgery,rats were executed 2h after morphine injection and the protein expression level of PSD95 in the spinal dorsal horn was detected by Western Blotting.Results Compared with SO group,50%PWT in NP group decreased,and the protein expression level of PSD95 increased.Compared with NP group,50%PWT in Mor group increased,and protein expression level of PSD95 decreased.Conclusion Acute morphine injection can reduce the expression of PSD95 protein in the spinal dorsal horn of rats with neuropathic pain.