Fig. 6
Effect of different preconditioning strategies on the paracrine potential of PDLSCs. Cells that underwent pre/non-preconditioning were cultivated in an ordinary culture medium for 72 h. The supernatant was then collected for ELISA. A–C The expression of IL-6, VEGF and TGF-β of different groups were measured with a microplate reader. [No matching letter (e.g.: a, b, c, d] above any two column charts represents a significant difference between these two groups (p < 0.05), while the appearance of any matching letters (e.g.: a, a) means that there is no significant difference among groups (p > 0.05). Data are expressed as mean ± SD)