Fig. 2

The activation of UPR in P-PD. a Transmission electron microscopy (TEM) images of the endoplasmic reticulum (ER) in P-PD and H-PD. The red box is the area of interest, and the blue arrow indicates the location of ER. b qRT-PCR was performed to detect the expression of UPR-related gene GRP78 and CHOP, inflammatory factor IL-6 and osteogenic differentiation markers RUNX2 in P-PD, H-PD, P-PD + OM, and H-PD + OM. c, d Western blot detected the UPR target protein IRE1α and the osteo-related proteins RUNX2 and ALP (c), and the corresponding relative expression levels were measured by ImageJ software (d). All data are presented as means ± SD (n = 3). The representative results were from three independent experiments (*p < 0 .05; **p < 0 .01; ***p < 0 .001; ****p < 0 .0001). P-PD, P-PDLSCs; H-PD, H-PDLSCs; P-PD + OM, P-PDLSCs + osteogenic medium; H-PD + OM, H-PDLSCs + osteogenic medium