Changes in the number of microglias snd astrocytes in the spinal dorsal horn in a rat model of phantom limb pain

Abstract

Objective To investigate the changes in the number of microglias and astrocytes in the spinal dorsal born in a rat model of phantom limb pain.Methods Eleven healthy adult SD rats of both sexes weighing 290-300 g were randomly divided into 2 groups:sham operation group (group S,n =5 ) and unilateral sciatic nerve transection group (group SNT,n =6).Phantom limb pain model was induced by resection of a 0.5 cm segment of unilateral sciatic nerve in group SNT.In group S unilateral sciatic nerve was exposed but not transected.The animals were observed for autotomy and scored (0 =no autotomy,13 =the worst autotomy) after operation and were sacrificed on the 28th day after operation.The L5 segment of the spinal cord was removed for determination of the number of microglials (by iba-1 immuno-histochemistry) and astrocytes (by GFAP immuno-histochemistry).Results In group S no animal developed autotomy.In group SNT autotomy started from the 2nd day after operation and the score reached 9-11.Compared with group S,the number of the microglias and astrocytes in the spinal dorsal horn was significantly decreased in the operated side in group SNT ( P ＜ 0.05 ).Conclusion The number of microglias and astrocytes in the spinal dorsal horn is decreased in animals with phantom limb pain. Key words: Acrodynia; Microglia; Mtrocytes; Posterior horn cells