鞘内注射甘珀酸剂量依赖地缓解腰5脊神经切断大鼠的痛觉高敏

摘要

目的观察鞘内注射甘珀酸（carbenoxolone，CBX）对腰5脊神经切断（L5 spinal nerve transaction ，SNT）大鼠的镇痛作用及其相关机制。方法60只♂SD大鼠，随机分成5组（n＝12）：Ⅰ．假手术组，Ⅱ．模型组，Ⅲ．SNT＋CBX（0.05μg），Ⅳ．SNT＋CBX（0.5μg），Ⅴ．SNT＋CBX（5μg）。Ⅰ组仅暴露腰5脊神经，Ⅱ至Ⅴ组行SNT。术后10 d，Ⅰ和Ⅱ组鞘内注射生理盐水10μL，Ⅲ至Ⅴ组注射CBX 0.05μg（10μL）、0.5μg（10μL）和5μg（10μL），分别于术前1 d，术后1、3、5、7、10 d各组注射生理盐水和CBX，前1 h和给药后1、2、4、6 h测双侧机械痛阈值（mechanical withdrawl thresholds MWT），免疫组化及ELISA法观察给药后2h后脊髓背角胶质纤维酸性蛋白（glial fibrillary acidic protein，GFAP）和TNF-α、IL-1β表达的变化。结果与术前相比，Ⅱ至Ⅴ组双侧MWT明显降低；与给药前1h相比，Ⅱ和Ⅲ组给药后1、2、4、6h双侧MWT均无明显差异；Ⅳ组损伤侧给药后1、2、4 h MWT无明显差异，而对侧MWT明显提高，同时该侧GFAP和TNF-α、IL-1β的表达也降低；Ⅴ组给药后1、2、4 h 双侧MWT明显提高，双侧GFAP和TNF-α、IL-1β的表达也明显降低。结论鞘内注射CBX可缓解SNT大鼠双侧MWT，其机制可能与其抑制脊髓背角星形胶质细胞的活化及TNF-α和IL-1β释放减少有关。%Aim Toinvestigatetheantagonisticeffect of intrathecal injection of carbenoxolone (CBX ) on neuropathic pain and its underlying mechanism.Meth-ods SixtymaleSprague-Dawleyratswererandomly divided into five groups (n =12 ):group I received sham surgery then treated with saline;group Ⅱ re-ceived SNT then treated with saline;groupⅢreceived SNT then treated with 0. 05 μg CBX;group Ⅳ re-ceived SNT then treated with 0. 5 μg CBX;group Ⅴreceived SNT then treated with 5 μg CBX.Treatment was undertaken with 10 μl volume as a single intrathe-cal injection on postoperative day 10.Mechanical with-drawl thresholds were measured 1 d before operation, 1,3,5,7 and 10 d after surgery,1 h before intrathe-cal administration,and 1 ,2,4,6 h after intrathecal administration.Lumbar spinal cord was obtained 2 h after intrathecal administration to determine the expres-sions of GFAP by immunohistology and TNF-α,IL-1βby ELISA in bilateral spinal dorsal horns.Results Comparedwiththeshamgroup,thebilateralMWTin group Ⅱ ~Ⅴ was significantly decreased.Compared with the MWT 1 h before intrathecal administration on day 10,the values at 1 ,2,4,6 h after administration of group Ⅱ and Ⅲ had no marked difference.The ip-silateral MWT in groupⅣhad no significant difference at 1,2,4 h after administration,the contralateral MWT was significantly increased,whereas GFAP and TNF-α,IL-1βwas significantly decreased in the spinal cord .In group Ⅴthe bilateral MWT was significantly improved at 1 ,2,4 h after administration,whereas GFAP and TNF-α,IL-1βwere significantly decreased inthespinalcord.Conclusions IntrathecalCBXcan inhibit the development of bilateral MWT.The analge-sic effect of CBX is implemented partly via suppressing the actation of GFAP and the realease of TNF-α,IL-1βin the spinal doral horn.