氢气对大鼠神经病理性疼痛镇痛作用的实验研究

Analgesic effect of hydrogen on neuropathic pain in rats

目的：探讨2％的氢气对慢性神经病理性疼痛大鼠的镇痛作用及最佳给药方式。方法雄性SD大鼠40只，体质量200～220 g，随机分为假手术组（ S组）、对照组（ C组）、腹腔注射氢气组（ AH组）、局部注射氢气组（ TH组）及局部注射氧气组（ TO组），每组8只。采用坐骨神经慢性压迫法（ CCI）制备大鼠神经病理性疼痛模型，S组仅暴露坐骨神经，不结扎。 C组结扎后不给予任何治疗，AH组、TH组及TO组在术后第5天测试机械痛阈及热痛阈值后，分别腹腔注射氢气2 mL、局部注射氢气2 mL、局部注射氧气2 mL，每天1次直到术后2周。各组分别在术前、术后1、3、5、7、14 d测定机械痛阈和热痛阈值。在术后14 d将每组大鼠处死，取腰段脊髓组织采用免疫组织化学方法检测神经胶质纤维酸性蛋白（ GFAP）和感觉神经肽P物质（ SP）的表达水平。结果与S比较，C、AH组、TH组及TO组术后1、3、5、7、14 d机械痛阈和热痛阈值降低；与C组和TO组比较，AH组、TH组在给予治疗后机械痛阈和热痛阈值升高，且术后14 d脊髓GFAP和SP阳性细胞数减少；与AH组比较，TH组机械痛阈和热痛阈值升高较明显，且GFAP和SP阳性细胞数明显减少，两组之间差异有统计学意义。结论氢气对神经病理性疼痛大鼠有镇痛作用，且局部给药效果较好。

Objective The present study aims to investigate the analgesic effect of 2%concentration hydrogen gas on chronic neurological pain in rats , and discuss the best drug -delivery way.Methods Forty male SD rats weighing 200-200 g were randomly divided into sham group （S）, control group （ C ） , abdominal cavity injection of hydrogen group （ AH ） , local injection of hydrogen group （ TH） and local injection of oxygen group （ TO ） with eight rats in each group .Using chronic compression injury of the ciatic nerve （ CCI） to prepare the neuropathy pain model in rats , S group only was exposed the sciatic nerve , without ligation .C group was not given any treatment after ligation , but AH group, TH group and TO group rats were tested mechanical pain threshold and thermal pain threshold in postoperative 5d, then respectively intraperitoneally injected with hydrogen 2 mL and locally injected with hydrogen 2 mL, locally injected with oxygen 2 mL, once a day until 2 weeks after CCI surgery.All groups were tested mechanical pain threshold and thermal pain threshold respectively in the preoperative and postoperative 1, 3, 5, 7 and 14 d.Forteen days after surgery all rats in each group were sacrificed , and the lumbar spinal cord tissues were taken to detect GFAP and SP expression level by the immunohistochemical method .Results Compared with S group , the mechanical pain threshold and thermal pain threshold were lower in other groups on postoperative 1, 3, 5, 7, 14 d.Compared with C group and TO group , the mechanical pain threshold and thermal pain threshold of AH group and TH group were increased after treatment , and GFAP and SP positive cells of spinal cord were reduced in 14 days after surgery .Compared with AH group , the mechanical pain threshold and thermal pain threshold of TH group were increased obviously , and GFAP and SP positive cells were significantly reduced; the two groups had significant difference .Conclusion Hydrogen has analgesia effect on CCI -induced neuropathic pain in rats , and the effect of local application is better .