Effects of mechanical stretch stress on the proliferation and differentiation of human stem cells from the ap-ical papilla / 医学研究生学报

ABSTRACT

Objective SCAP are seen as seed cells of peri-apical tissue regeneration and used in periapical tissue regeneration project based on stem cells .In this study, we aim to explore the ef-fectdifferent mechanical stretch stress on the proliferation and differen-tiation potential of human stem cells from the apical papilla ( SCAP ) ,and to clarify the mechanism of how mechanical stretch stress regulate human SCAP ,which will provide theoretical guidance for ortho-dontic treatment . Methods Human SCAP was isolated , cultured and identified by combined explants method and enzymatic separa-tion method and limited dilution .MTT assay was used to detect the effect different static mechanical stretch stress stimulation have on the proliferation of SCAP .Western blot was used to detect the expression changes of SCAP osteogenesis /odontoblast differentiation-re-lated protein (ALP, OSX,DSP) under mechanical stretch stressand to detect the expression of SCAP endoplasmic reticulum stress mo -lecular chaperone GRP 78 under different static mechanical stretch stress . Results SCAP were successfully isolated and cultured , and we induced SCAP to differentiate into osteoblasts and adipocytes successfully by osteogenic medium and adipogenic medium .Flow cytometry was performed in accordance with SCAP immunophenotype .Compared with the control group , 150g mechanical stretch stress stimulation promoted SCAP proliferation first and then inhibited SCAP proliferation [(0.481±0.226),(1.375±0.104),(1.425± 0.136),(1.556±0.268),(0.589±0.29),P<0.05].It was same in the 200g group.250g mechanical stretch stress stimulation signifi-cantly inhibited SCAP proliferation [(0.373±0.146),(0.545±0.069),(0.745±0.273),(0.967±0.278),(1.060±0.362),P<0.05]. The expression levels of ALP , OSX and DSP protein in each group were higher than those in the control group (P<0.05).Compared with the control group, the expression of GRP78 protein was up-regulated (P<0.05). Conclusion Mechanical stretch stress could regulate the SCAP proliferation and osteogenesis/odontoblast differentiation .What′s more,endoplasmic reticulum stress played a role in osteogenesis/odontoblast differentiation under mechanical stretch stress and promoted SCAP osteogenesis /odontoblast differentiation .