Résumé
Objective To investigate the changes of the expression of GDNF and GDNFR?1 of long-term denervation of posterior cricoarytenoid muscles(PCAMs).Methods 38 patients with vocal paralysis were grouped into four according to their denervated period of time while 12 normal PCAMs as control group.Using double immunofluorescence stain,changes of GDNF and GDNFR1 expression were observed in myofibers at different time points after denervation.Results Double immunofluorescence stain with antibodies against GDNF and GDNFR1 showed no staining in the control group,and study groups.However,after the muscle denervation lasted for 6-12 months and 1-2 years,noted was a significant accumulation of GDNF and GDNFR1 protein in cytolemma and endochylema of myofiber.The mean grey scales and positive region ratios were compared using the image analysis system.The results revealed the levels of GDNF and GDNFR1 protein expression in 6-12 months group,1-2yr group changed significantly(P0.05).Conclusion The changes in expression of GDNF and the acceptor GDNFR-?1,a powerful neurotrophic factor,implied that a good nervous regenerated microenvironment in PCAMs within 2 years.This experiment indicated that denervated posterior cricoarytenoid muscles are able to regain their functions through reinneration within 2 years.