Changes in expression of Nogo-A protein in dorsal root ganglion and spinal dorsal horn in a rat model of inflammatory pain / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the changes in the expression of Nogo-A protein in the dorsal root ganglion (DRG) and spinal dorsal horn in a rat model of inflammatory pain.Methods One hundred and twenty male Sprague-Dawley rats,weighing 250-300 g,were randomly divided into 2 groups (n =60 each)control group (group C) and formalin group (group F).The inflammatory pain was induced by injection of 3％ formalin 100 μl into the plantar surface of left hindpaw in group F.The equal volume of normal saline was given instead of formalin in group C.Mechanical withdrawal threshold to yon Frey filament stimulation was measured at 1 h and 1,2,3 and 7 days after injection.Twelve rats in each group were chosen at each time point and sacrificed.The L5 DRG and L4,5 segment of spinal cord on the operated side were removed for determination of Nogo-A protein expression by immunofluorescence and Western blot.Remlts Compared with group C,the mechanical withdrawal threshold was significantly decreased at 1 h,1,2,3 and 7 days after injection,and the expression of Nogo-A protein in the DRG and L4,5 segment of spinal cord was up-regulated at 1 h and 2,3 and 7 days after injection in group F (P ＜0.05).Conclusion Up-regulation of Nogo-A protein in the DRG and spinal dorsal horn may play an important role in the development of formalin-induced inflammatory pain in rats.