Human periodontal ligament and gingival fibroblast response to TGF-beta 1 stimulation

The purpose of this study was to measure the time-sequence response of RNA and protein synthesis to transforming growth factor-beta 1 (TGF-beta 1) by human periodontal ligament (HPDLF) and gingival (HGF) fibroblasts in culture. HPDLF and HGF were cultured from explants of healthy gingival tissue and freshly extracted teeth. Cultures of 8 x 10(4) cells/ml were exposed to medium containing 3H-uridine and 35S-methionine with TGF-beta 1 at concentrations from 10(-9) M to 10(-21) M, or control medium, for up to 60 hours in order to assess RNA and protein synthesis. Protein concentrations of comparable cultures were also assayed colorimetrically. Results were reported as specific activity (CPM/microgram protein). The results indicate that 10(-9) M TGF-beta 1 treated cultures showed a significant increase in RNA synthesis by HPDLF and HGF over time, as compared to the control cultures. HPDLF showed a significant increase in protein synthesis over time while that by HGF was not significant as compared to the control cultures. Lower concentrations of TGF-beta 1 demonstrated no significant differences from control. Results suggest that the effects of TGF-beta 1 on HPDLF and HGF are both time and dose dependent, with 10(-9) M TGF-beta 1 providing the best response of those concentrations tested. These findings support the concept that TGF-beta 1 may play a role in periodontal regeneration due to its ability to promote fibroblast RNA and protein synthesis. The results also demonstrate that although these two cells types appear morphologically similar, they exhibit distinct biological responses to growth factors such as TGF-beta 1.