The purpose of the present study was to compare
protein and matrix molecular (
collagen and
fibronectin) metabolism among fibroblasts cultured from two types of hyperplastic gingiva and normal tissues. Cell cultures were obtained from tissue explants of normal gingiva, the periodontal ligament (PDL), and
phenytoin-induced and idiopathic fibromatotic gingiva. The synthetic capacity of matrix
proteins of each isolated fibroblast type was studied by metabolic labeling (3H-proline), biochemical purification and characterization. Our results showed that fibroblasts derived from
phenytoin-induced
gingival hyperplasia synthesized a greater amount of total
protein and
collagen than the rest of the cell types, based on both the amount of total
protein and
protein/micrograms
DNA. In contrast, fibroblasts obtained from idiopathic
gingival fibromatosis exhibited a similar potential for both
protein and
collagen synthesis as normal gingival and PDL fibroblasts. Normal PDL fibroblasts displayed a significantly higher degree of
collagen synthesis than normal gingival fibroblasts; however, no difference in
protein production between them was noted. A few variations in
fibronectin synthesis/microgram
DNA among various fibroblasts from normal and hyperplastic tissues were noted. PDL fibroblasts seemed to produce a greater amount of
fibronectin than all of the other cell types. Interestingly, fibroblasts obtained from idiopathic
gingival fibromatosis showed a higher
DNA content than other fibroblasts, although a decrease in synthesized
fibronectin/microgram
DNA was noted. In conclusion, the pathogenic mechanism of
phenytoin-induced
hyperplasia and idiopathic
gingival fibromatosis may be different due to their distinct profile of cell proliferation and matrix
protein synthesis.