Objective:This study aimed at investigatingwhetherPEGF-BB and PDGF-RBBwere involved in the pathogenesis of oral sub- mucous fibrosis.Methods:Immunoelectronmicroscopywas used for the study of the ultrastructural localization of PDGF-BB and re- ceptors of PDGF-RBBin 6 cases of specimens of oral submucous fibrosis. Each specimen was divided into two parts, consisting of one part for HE staining for pathological staging and the other partfor transmission electronic microscopic observation.Results:Im- munoreactive products of PDGF-BB and its receptorsmainly existed in the cellularplasm of epithelial cells, fibroblasts and vascular endothelial cells, with enlargement of acanthoid cells, swollen mitochondria and abnormal ridges. Immunoreactive products were found on the membrane of epithelial cells, aswell as in the mitochondria, rough endoplasmic reticula and on the membrane of the fibroblasts. Immunoreactive products of PDGF-RBBmainly existed in the rough endoplasmic reticula of fibroblasts and in the cell membrane of acanthoid cells, and also could be found sometimes in the rough endoplasmic reticula of vascular endothelial cells. No immunoreactive productwas found in the normal oral mucous membrane.Conclusion:The findings suggest that PDGF-BB and PDGF-RBBmight play an important role in the pathophysiological process of oral submucous fibrosis.
