Aberrant keratinization of reticular oral lichen planus is related to elastolysis.

OBJECTIVE

Aberrant keratinization is common in oral lichen planus (OLP) on buccal mucosa. Because elastin is crucial for maintaining the nonkeratinized phenotype of oral mucosa, we examined whether inflammatory elastases and the accompanying elastolysis were related to this feature.

STUDY

DESIGN

Protein and mRNA levels of keratinization-associated keratins (K1/10), nonkeratinization-associated keratins (K4/13), elastin, neutrophil elastase, and macrophage metalloelastase (MMP-12) were compared between normal alveolar mucosa and reticular OLP from buccal mucosa. Normal alveolar mucosae were cultured ex vivo on an organ culture system with and without elastase treatment. After 14 days, the mucosae were examined for 4 keratin expressions.

RESULTS

The expressions of K1/10 and elastases increased, whereas those of K4/13 and elastin decreased in OLP. The nonkeratinized mucosa in the organ culture began to express K1/10 when elastase degraded the inherent elastin.

CONCLUSIONS

Our study demonstrated that elastolysis in reticular OLP may be related to its aberrant keratinization.