神经病理性痛大鼠鞘内注射人前脑啡肽原基因修饰骨髓间充质干细胞的镇痛效果

Analgesic effect of intrathecal human bone marrow mesenchymal stem cells genetically modified with human proenkephalin gene in a rat model of neuropathie pain

目的 探讨神经病理性痛大鼠鞘内注射人前脑啡肽原（PENK）基因修饰人骨髓间充质干细胞（hMsc）的镇痛效果。方法取鞘内置管成功的健康雄性SD大鼠40只，周龄6～8周，体重160～180g，随机分为。4组（n=10），A组为正常对照组；B组、c组和D组采用坐骨神经慢性压迫性损伤（CCI）法建立神经病理性痛模型，于CCI术后3d鞘内给药，A组和B组鞘内注射生理盐水10出；c组鞘内注射转染空载体的hMSC细胞（hMSC．pBABE）悬液10出（2×108-3×10^8/μl）；D组鞘内注射hMSC-PENK细胞悬液10m（2×10^8～3×10^8个／μl）。于术前、术后3、5、7、9、14d时测定热痛阈。术后14d痛阈测定后取新鲜脊髓组织，采用RT-PCR法测定PENKmRNA表达。结果与术前比较，B组、c组、D组术后各时点热痛阈降低（P〈0．05）。与A组比较，B组、c组、D组热痛阈降低，B组和c组PENKmRNA表达下调，D组PENKmRNA表达上调（P〈0．05）。与B组和C组比较，D组热痛阈升高，PENKmRNA表达上调（P〈0．05）。B组和c组各指标比较差异无统计学意义（P〉0．05）。结论大鼠鞘内注射PENK基因修饰的hMSC可减轻神经病理性痛。

Objective To investigate the analgesic effect of intrathecal （IT） human bone marrow mesenchymal stem cells （hMSC） genetically modified with human proenkephalin gene （PENK） in a rat model of neuropathic pain. Methods Forty male SD rats weighing 160-180 g in which IT catheters were successfully implanted without complication were randomly divided into 4 gorups （ n = 10 each） ： group A normal control ; group B neuropathic pain （NP） ; group C NP ＋ hMSC-pBABE and group D NP ＋ hMSC-PENK. Neuropathic pain was induced with chronic constrictive injury （CCI）. Four loose ligatures were placed on the main stem of sciatic nerve with 4-0 chronic catgut. IT normal saline 10 μl, hMSC-pBABE cell suspension 10 μl （2 × 10^8-3 ×10^8/μl） and hMSC- PENK cell suspension 10 μl （2 × 10^8-3 ×10^8/μl） were injected in group B, C and D respectively on the 3rd day after operation. Paw-withdrawal latency （PWL） to noxious thermal stimulation was measured before （baseline） and at 3, 5, 7, 9 and 14 d after operation. The animals were killed on the 14th day after last PWL measurement. RNA was extracted from the spinal cord for determination of proenkephalin mRNA expression. Results PWL was significantly decreased after operation as compared with the baseline values before operation in group B, C and D. PWL was significantly longer at 7, 9, 14 d after operation in group D than in group B and C but there was no significant difference in PWL after operation between group B and C. PENK mRNA expression was significantly lower in group B and C than in group A, but was significantly higher in group D than in group B and C. There was no significant difference in PENK mRNA expression between group B and C. Conclusion Intratheccal human bone marrow mesenchymal stem cells genetically modified with human proenkephalin gene can relieve neuropathic pain in rats.