Evaluation of Collagen in Leukoplakia, Oral Submucous Fibrosis and Oral Squamous Cell Carcinomas Using Polarizing Microscopy and Immunohistochemistry.

Objectives: Picrosirius red and MMP are capable of degrading extracellular matrix proteins, expressed in lesions such as squamous cell carcinomas. The present study was undertaken with an aim to analyze and compare changes in collagen using Picrosirius red staining under polarizing microscopy and immunohistochemical staining using anti MMP-13 in samples of oral leukoplakia, oral submucous fibrosis and oral squamous cell carcinoma. Materials and Methods: A total of 70 slides were prepared and divided into 3 groups. Group I comprised 10 slides of normal gingival tissue, Group II 40 slides of potentially malignant disorders and Group III 20 slides of well differentiated oral squamous cell carcinoma. Half the slides for each group were stained with Picrosirius red stain and the remainder with antibodies to MMP-13. Rerults: In Group II, MMP-13 connective tissue expression was greater in OSMF as compared to leukoplakia. Group III showed elevated expression among 70% of cases. Picrosirius red staining in Group II cases, showed higher staining Yellow-Orange andGreen-Yellow mature fibers in OSMF than leukoplakia cases while in Group III, 50% OSCC cases showed Green-yellow stained immature thin fibers. Conclusion: In future, therapeutic measures targeted against MMP-13 may inhibit collagenolysis to some extent and delay spread of tumors. An easy and reliable method to determine the state of the stroma in such cases may be Picrosirius red staining with polarizing microscopy.