Changes of GDNF and NCAM expressions in dorsal root ganglion in rats with chronic constriction injury of sciatic nerve

Objective To observe the changes in the expressions of glial cell-derived neurotrophic factor(GDNF) and neural cell adhesion molecule(NCAM) in dorsal root ganglion(DRG) in rats with chronic constriction injury(CCI) of sciatic nerve.Methods Forty-two adult SD rats were randomly divided into group CCI and group C with 21 rats each.The rats in group CCI underwent ligation of the left sciatic nerve to establish the CCI models and those in group C received sham operation as the controls.Mechanical and thermal thresholds were determined on the day before operation and on the 1st,3rd,5th,7th,14th and 21st postoperative day.The expressions of GDNF and NCAM in DRG were detected by immunohistochemistry and Real time-PCR.Results Mechanical and thermal thresholds were lower(P0.01) and the expressions of GDNF and NCAM were higher in group CCI than those in group C on the 3rd,5th,7th and 14th postoperative day(P0.05 or P0.01).Conclusion Sciatic never ligation may cause the decrease in pain threshold associated with the increase in the expressions of GDNF and NCAM in DRG.