Evaluation of the anti-fibrotic effect of thymoquinone in the management of oral submucous fibrosis.

Oral submucous fibrosis (OSMF) is a potentially malignant disorder. Since decades, many treatment modalities have been in use but complete regression is still not achieved. This study evaluated the therapeutic effects of thymoquinone in OSMF and compared its effects with lycopene. OSMF model was established by administering bleomycin (1 mg/ml) into rats buccal mucosa for 8 weeks. Thymoquinone (25 mg/kg) and lycopene (5 mg/kg) were given to rats with OSMF and changes in body weight, mouth opening, gross morphological appearance of oral mucosa, and inflammatory cells count, antioxidant enzymes activity and mRNA expression of collagen type I and III were evaluated. Histological changes in buccal tissue were evaluated by H&E, Van Gieson and Masson's trichrome staining. Thymoquinone significantly increased the body weight and mouth opening which was reduced in diseased group. It also increased antioxidant enzymes activity. It alleviated signs of disease as gross morphological score was reduced. It also reduced the inflammatory cells count, expression of collagen type I and III and pathological features of disease. Thymoquinone can be a promising agent against OSMF and it acts by regulating inflammation, oxidative stress and especially fibrosis by lowering collagen type I and III deposition in extracellular matrix.