Epigallocatechin gallate affects the proliferation of human alveolar osteoblasts and periodontal ligament cells, as well as promoting cell differentiation by regulating PI3K/Akt signaling pathway.

Human periodontal ligament cells (hPDLCs) and human alveolar osteoblasts (hAOBs) play pivotal roles in periodontium. The regulatory effects of epigallocatechin gallate (EGCG) on hPDLCs and hAOBs remained unclear. This study probed into the functions of EGCG treating periodontal diseases. Cultured hAOBs and hPDLCs were passaged and observed by microscopic examination, and alkaline phosphatase (ALP) and immumohistochemical staining were performed for verification. hAOBs and hPDLCs were treated with EGCG and LY294002 + EGCG, then the proliferation of the two cells was assayed by MTT. Mineralization of the treated hAOBs and hPDLCs was detected by ALP activity experiment and Alizarin Red S staining kit. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting were performed for the detection of the expressions of differentiation-related mRNAs and PI3K/Akt signaling pathway-related proteins in the two cells. The third passage of hAOBs mainly showed triangle shape and were positive by ALP staining. hPDLCs in passage 3 adhered to the wall in spiral or radial pattern with positively stained vimentin and negatively stained keratin. Cell proliferation and ALP activity of the hAOBs and hPDLCs were increased by EGCG treatment. The mineralized nodules and expressions of differentiation-related mRNAs, the phosphorylation of PI3K and Akt of the hAOBs and hPDLCs were promoted by EGCG treatment, while the effects of LY294002 treatment were opposite to EGCG treatment. Epigallocatechin gallate affected the proliferation and differentiation of hAOBs and hPDLCs through regulating PI3K/Akt signaling pathway.