鞘内注射PSD-93反义寡核苷酸对神经病理性痛大鼠脊髓nNOS的影响

目的 探讨鞘内注射PSD-93反义寡核苷酸对神经病理性痛大鼠脊髓神经型一氧化氮合酶(nNOS)的影响.方法 雄性SD大鼠32只,体重250～350 g,随机分为4组(n=8):假手术+生理盐水组(C组);C7脊神经压迫+生理盐水组(N组);C7脊神经压迫+PSD-93误义寡核苷酸10μg组(M组);C7脊神经压迫+PSD-93反义寡核苷酸10μg组(A组).N组、M组和A组采用60 g微血管夹压迫大鼠右侧C7脊神经15 min制备神经病理性痛模型,经枕骨大孔鞘内置管至颈膨大处.术毕当日开始给药,每日1次,连续4 d.于术前2 d(T0)、术后1、3、5和7 d(T1-4)时测定机械痛阈和热痛阈,术后7 d处死大鼠取C7段脊髓,免疫组化法检测神经压迫侧脊髓PSD-93蛋白和nNOS的表达.结果 与T0时比较,N组和M组各时点机械痛阈及热痛阈降低(P<0.05);与C组比较,N组和M组各时点机械痛阈及热痛阈降低,N组、M组和A组脊髓背角PSD-93蛋白和nNOS表达上调(P<0.05);与N组和M组比较,A组各时点机械痛阈及热痛阈升高,脊髓背角PSD-93蛋白和nNOS表达下调(P<0.05).结论 鞘内注射PSD-93反义寡核苷酸可抑制神经病理性痛大鼠脊髓nNOS表达,nNOS在神经病理性痛中的作用可能受PSD-93蛋白调节.

Effects of intrathecal PSD-93 antisense oligonucleotide on meuronai nitric oxide synthase in spinal cord in a rat model of neuropathic pain

Objective To evaluate the effects of intrathecal (IT) PSD-93 antisense oligonucleotide (ASODN) on neuronal nitric oxide synthase (nNOS) in the spinal cord in a rat model of neuropathic pain. Methods Thirty-two male SD rats weighing 250-350 g were randomly divided into 4 groups ( n = 8 each) : group Ⅰsham operation; group Ⅱ C7 spinal nerve compression (C7 SNC ); group Ⅲ C7 SNC + mismatch oligonucleotide (MSODN) 10 μg and group Ⅳ C7 SNC + ASODN 10 μg. The animals were anesthetized with intraperitoneal 10% chloral hydrate 350 mg/kg. Neuropathie pain was produced by clamping the right C7 spinal nerve for 15 min with a 60 g mini-clamp (C7 SNC). A catheter was inserted into the subarachnoid space via foramen magnum. The tip of the catheter reached cervical enlargement. MSODN and ASODN were administered IT once a day for 4 consecutive days after operation in group Ⅲ and Ⅳ respectively. In group Ⅰ and Ⅱ normal saline (NS) was injected IT instead. Paw withdrawal threshold (PWT) to noxious thermal and mechanical stimuli was measured 2 days before surgery (T0 baseline) and on 1st, 3rd, 5th and 7th day after operation (T1-4). All rats were killed on the 7th day after operation and the C7 segment of the spinal cord was removed for determination of the expression of PSD-93 protein and nNOS in the spinal cord on the SNC side by immuno-histocbemistry.Results The mechanical and thermal pain threshold at T1-4 were significantly decreased as compared with the baseline values at To in group Ⅱ and Ⅲ and were significantly lower than those in group Ⅰ . The expression of PSD-93 protein and nNOS in the dorsal horn of the spinal cord on the SNC side was significantly higher in group Ⅱ , Ⅲ and Ⅳ than in group Ⅰ but was significantly decreased by IT ASODN in group Ⅳ as compared with group Ⅱ and Ⅲ. Conclusion Intrathecal PSD-93 ASODN can inhibit the expression of nNOS in the spinal cord in rats with neuropathic pain. The role of nNOS in reducing neuropathic pain may be modulated by PSD-93 protein.