Gene expression of extracellular matrix proteoglycans in human cyclosporin-induced gingival overgrowth.

Background: Gingival overgrowth is one of the side effects associated with the systemic use of cyclosporin A (CsA). In vitro studies on the extracellular matrix of gingival tissues have demonstrated an altered composition, particularly an accumulation of proteoglycans and collagen. We investigated the gene expression of extracellular matrix proteoglycans in CsA-induced gingival tissue alterations.

Methods: mRNA expression of the proteoglycans perlecan, decorin, biglycan, and versican was analyzed by reverse transcription polymerase chain reaction (RT-PCR) in gingival samples obtained from 12 individuals, six with CsA-induced gingival overgrowth (CsA group) and six with a normal gingiva (control group). The RT-PCR products were subjected to 1% agarose gel electrophoresis containing ethidium bromide and analyzed qualitatively and semiquantitatively by densitometry. Density values were normalized by determining the expression of the housekeeping gene beta-actin in the same sample. Groups were compared by the Student's t test.

Results: Perlecan expression showed a marked increase (54%) in the CsA group compared to the control group (P < 0.01), while no significant differences were observed for the other proteoglycans.

Conclusion: CsA-induced gingival overgrowth seems to be associated with increased expression of perlecan, a typical basement membrane proteoglycan, but not decorin, biglycan, or versican.