Experimental Studies On The Relationship Between Expression Characteristics Of EGF,EGFR,bFGF,PCNA And Recurrent Aplthous Ulcer Formation

Objective: To investigate the expression characteristics and distribution of EGF, EGFR, bFGF and PCNA in recurrent oral aphthous (RAU) and normal oral mucosa at protein and mRNA level in order to explore the mechanisms involved in RAU formation.Material and Methods: 14 biopsies from normal oral mocusa (n=6) and RAU tissues (n=8) were obtained from surgical operation in our hospital. After excision, subcutaneous tissues were carefully removed from the lower dermal layer. All samples were cutted into 2 portions. One portion was frozen within 30 seconds after excision for RNA isolation. Another portion was fixed in 10% formalin immediately for immunohistochemical examination. The expression characteristics and distribution of EOF, EGFR, bFGF and PCNA in normal and RAU tissues were examined with immunohistochemical method. The mRNA transcript contents of EGF, EGFR, bFGF and 3 -actin were examined with reverse transcription-polymerase chain reaction analysis (RT-PCR). Histological examination was made with light microscop.Results: In RAU tissue, there were many inflammatory cells. In normal oral mucosa, the expression intensity of PCNA was significant higher than that in RAU (P<0.05). In normal oral mocusa, immuno-staining of EGF was mainly localized in basal layer cells and prickle layer cells and the expression intensity of EGF was higher than that in RAU (PO.05), while the gene expression of EGF was no difference between RAU and normal mocusa. In normal oral mucosa, the expression intensity of EGFR was higher than that in RAU(P<0.05), while the mRNA expression of EGFR was also significantly decreased in RAU. In normal oral mucosa, the location of bFGF expression was mainly observed in extracellular matrix in mucosa basal cells and fibroblasts in lamina propia. In RAU, bFGF was mainly expressed by inflammatory cells and vascular endothelial cells; the expression intensity was significant higher than that in normal mucosa (P<0.05), which was consistent with bFGF gene transcription. Conclusion: RAU is one of the chronic inflammatory diseases. The epithelial cell proliferation level was decreased in RAU versus normal mucosa, in which the significant decrement of protein contents of EGF and EGFR might be involved. The reduction of EGF expression may be affected at the translation level. The expression enhancement of bFGF in RAU suggested that this growth factor may play an important role in RAU formation, immunologic reaction and wound healing.