INCREASED EXPRESSION OF TYPE-VI COLLAGEN GENES IN DRUG-INDUCED GINGIVAL ENLARGEMENT

Fibrotic gingival enlargements induced by phenytoin or nifedipine were examined with special reference to type VI collagen expression. Immun olocalization studies showed abnormal accumulation of type VI collagen around the collagen fiber bundles in the fibrotic gingival enlargemen ts. Examination of total RNA extracted from fibroblasts and tissues of enlarged gingivae demonstrated increased type VI collagen steady-stat e mRNA levels. These results suggest that excessive deposition of type VI collagen in drug-induced gingival enlargement is attributed to inc reased expression of the collagen genes.