TGF-β promotes the proliferation and osteogenic differentiation of dental pulp stem cells a systematic review and meta-analysis

Background Dental pulp stem cells (DPSCs) are adult stem cells with multi-directional differentiation potential derived from ectoderm. Vitro experiments have shown that adding cytokines can help DPSCs to be transformed from multipotent stem cells to osteoblasts. TGF-beta has been proved to have an effect on the proliferation and mineralization of bone tissue, but its effect on the osteogenesis and proliferation of dental pulp stem cells is still uncertain. We aim to determine the effect of TGF-beta on the osteogenesis and proliferation of dental pulp stem cells. Methods We have identified studies from the Cochrane Central Register of Controlled Trials, PubMed, Embase, and China national knowledge infrastructure (CNKI) for studies interested in TGF-beta and proliferation and differentiation of dental pulp stem cells in the following indicators: A490 (an index for evaluating cell proliferation), bone sialoprotein (BSP), Col plasmid-1 (Col-1), osteocalcin (OCN), runt-related transcription factor 2 (Runx-2); and the number of mineralized nodules. Any language restrictions were rejected. Furthermore, we drew a forest plot for each outcome. We conducted a sensitivity analysis, data analysis, heterogeneity, and publication bias test. We evaluate the quality of each study under the guidance of Cochrane's tool for quality assessment. Results The pooled data showed that TGF-beta could promote the proliferation and ossification of dental pulp stem cells. All the included results support this conclusion except for the number of mineralized nodules: TGF-beta increases the A490 index (SMD 3.11, 95% CI [0.54-5.69]), promotes the production of BSP (SMD 3.11, 95% CI [0.81-6.77]), promotes the expression of Col-1 (SMD 4.71, 95% CI [1.25-8.16]) and Runx-2 (SMD 3.37, 95% CI [- 0.63 to 7.36]), increases the content of OCN (SMD 4.32, 95% CI [1.20-7.44]) in dental pulp, and has no significant effect on the number of mineralized nodules (SMD 3.87, 95% CI [- 1.76 to 9.51]) in dental pulp stem cells. Conclusions TGF-beta promotes the proliferation and osteogenesis of dental pulp stem cells.