Investigation Of The Differential Expression Of BFGF In Oral Submucous Fibrosis And Oral Leukoplakia

Objective: To investigate the different expression of basic fibroblastgrowth factor(bFGF) between oral submucous fibrosis(OSF) and oralleukoplakia(OLK), so as to evaluate the carcinogenic ability of OSF anddiscuss the role of bFGF in the development of OSF.Materials and Methods: 1. 10 normal buccal mucosae(NBM) ofhealthy persons, 15 cases of OSF mucosae(comprises of 5 early, 5medium-term and 5 advanced stage cases) and 15 cases of OLKmucosae(consists of 5 mild, 5 moderate and 5 heavy displasia cases) werestudied. Three groups of specimens above were divided into two piecesrespectively, one was fixed by formalin and embedded by paraffin forHematoxylin and Eosin staining and immunohistochemical analysis, theother was dipped in liquor nitrogen instantly, then kept in -86℃refrigerator for Western Blotting.2. Evaluate the different expression of bFGF in these cases byimmunohistochemical analysis.3. Validate the expression of bFGF in these cases by WesternBlotting. Results: 1. NBM showed negative or weakly positive expression ofbFGF. Slight yellow staining could be mostly seen in basal membraneand plasm of basal cells. There was an upgrade of bFGF expression atearly stage of OSF, which was sporadically located in basal membrane,plasm of basal cells and lower layer of spinous cells and gaps betweenspinous cells. But staining in nuclei was seldom observed. Flaky positiveexpression of bFGF was exhibited in basal membrane, plasm of basalcells, upper and lower layer of spinous cells and gaps between spinouscells in medium-term stage of OSF, and some nuclui showed yellowstaining. In the advanced stage of OSF, major plasm and nuclei ofspinous cells presented brown staining. Sporadic yellow staining waspresented in basal cells, plasm and nuclei of spinous cells and gapsbetween spinous cells in mild dysplasia of OLK. Moderate dysplasia ofOLK showed intensive staining in these areas. However, there was even afull-thickness epithelium positive expression and deep brown staining ofnuclei in heavy dysplasia of OLK.2. The positive cell rates of bFGF in OSF and OLK were higher thanthose in NBM, but the gray scales were lower(P＜0.05). OLK ownedhigher positive cell rates and lower gray scales than those of OSF, and thedifference had an important significance(P＜0.05). The ascending ofpositive cell rates and descending of gray scales were related to thepathological degrees aggravation in OSF(P＜0.05). 3. The results of Western Blotting identified bFGF was weaklyexpressed in NBM which presented slightly protein bands of 18kD.However, the protein bands of 18kD and 24kD were observed in bothOSF and OLK, and the intensification trend was consist with theaggravation of pathological grades. The ratios of protein absorbance inNBM were lower than those in OSF and OLK(P＜0.05). The OSF showedascending ratios of protein absorbance with aggravation of pathologicaldegrees(P＜0.05), but lower than those of OLK(P＜0.05).Conclusion: 1. The bFGF obviously presented in OSF and itsstaining intensity enhanced with the aggravation of pathological grades. Itwas supposed that the bFGF played an important role in the initiation anddevelopment in OSF.2. The carcinogenic ability of OSF was lower than OLK's in theaspect of bFGF. The 24kD bFGF may involve in the carcinogenesis.