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Platelet-derived growth factor (PDGF) and transforming growth factor-beta (TGF-(3) are well characterized peptides which are known to function in the regulation of mesenchymal cell proliferation. Connective tissue cells are important in periodontal tissue regeneration and degradation. And in order to understand both the development and the differentiation of normal tissues, it is necessary to study the nature and regulation of the normal cell cycle. The purpose of present study is to investigate on the growth pattern and expression of cell cycle regulatory proteins in human gingival fibroblasts (GFs) exposed to PDGF-BB and TGF-,61. GFs were obtained from healthy gingivP_ by crown. lengthening procedure. These .cells were cultured in 10% FBS supplemented with either 10ng/mE TGF- 81, 20ng/m1 PDGF, or both. Cell proliferation rate was determined by the cell number count, MTT assay and cell density. Western blot analysis was performed. using antibodies of p21, cdk 2, 4, 6, and cyclin DI, E. PDGF-BB notably increased cell proliferation in the GFs themselves as compared to TGF- 81 or combination of both. It also slightly increased expression of cdk 2, 4, and cychn Dl, along with increasing of p21 expression, in these cells. These results indicate that the increase of cell proliferation by PDGF-BB and TGF- $1, especilly PDGF-BB may be due to the increased expression of cdks without the effect of p21 in human GFs.
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