Evaluation of Oxidative Stress Marker 4-hydroxynonenal in Oral Submucous Fibrosis: An Immunohistochemical Study

Oral submucous fibrosis (OSF) is a chronic and progressive fibrotic condition affecting the oral cavity and oropharynx, with a reported malignant transformation (MT) rate ranging from 1.9% to 10%. It is characterized by subepithelial fibrotic changes accompanied by epithelial alterations. The primary etiological factors include betel quid chewing and tobacco use. Habitual use of tobacco results in sustained exposure to reactive oxygen species, leading to oxidative stress (OS), which plays a crucial role in the pathogenesis and progression of OSF.

The objective of this study was to evaluate and compare the role of OS by assessing the immunohistochemical (IHC) staining intensity of 4-hydroxynonenal (4-HNE), a marker of lipid peroxidation (LPO), in OSF tissue samples and normal mucosal tissue.

The study included 30 formalin-fixed, paraffin-embedded tissue blocks of OSF and 10 normal oral mucosa samples as controls. Tissue sections of 5 μm thickness were prepared and subjected to IHC staining. The stained slides were examined under a light microscope, and the data were analyzed statistically using Fisher's exact test.

OSF tissue samples exhibited significantly higher 4-HNE expression than normal mucosa; a significant difference (P < 0.001) was also observed between the early and advanced stages of the disease.

The increased expression of LPO markers in OSF tissue samples underscores the involvement of OS in the advanced stages of the disease. Further studies incorporating clinicopathological correlations are crucial for early prediction of MT in OSF and for the development of targeted therapeutic strategies.