Effect of intrathecal injection of carbenoxolone on hyperalgesia in rats with L5 spinal nerve transaction / 中国药理学通报

ABSTRACT

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.