Protein production by human gingival fibroblasts is enhanced by guanidine EDTA extracts of cementum.

Abstract

Nonconfluent cultures of human gingival fibroblasts were exposed to both guanidine and guanidine EDTA extracts of cementum for 48 hours. To compare the effects of cementum extracts on fibroblasts with other mineralized tissue extracts, cells were also exposed to guanidine and guanidine EDTA extracts of dentin and alveolar bone. The cells were radioactively labeled during the last 24 h. Total protein production was measured via the incorporation of radioactive proline. Collagen production was estimated by digestion of the radioactive protein mixture with bacterial collagenase. All guanidine EDTA extracts elicited statistically significant increases in total protein production compared to controls. At 50 μg/ml of extract, the increases in protein production were 340%, 143% and 338% for bone, cementum and dentin, respectively. Similar results were obtained for collagen production. In contrast, the guanidine extracts had no effect on either protein or collagen production by human gingival fibroblasts. These data indicate that the functions of gingival fibroblasts can be altered by proteins from associated mineralized tissues. Identifying such proteins and understanding their biological functions will enhance our knowledge of the mechanisms that regulate connective tissue regeneration.