The influence of 3D-printed polycaprolactone scaffolds coated with platelet-rich plasma on the biological functions of dental pulp cells

Objective To study the influence of different 3D-printed polycaprolactone scaffolds coated with platelet-rich plasma on the adhesion, proliferation and differentiation of dental pulp cells (DPCs) . Methods DPCs were seeded on the scaffold of three groups. Cell attachment, proliferation and ALP activity were evaluated with immunofluorescence staining, CCK-8 assay and ALP kit, respectively. The expression of osteogenic genes was determined with RT-PCR. Results More cell attachment was found on the freeze-dried PRP-PCL scaffold (1999.33/field) than the rest (1043.33 and 843.00/field, F= 19.36, P<0.01) . In the cell proliferation test, the amount of cells was increased in all groups but there was no statistically significant difference between groups of the same day. The number of migrated cells at the bottom of the transwell chamber in the freeze-dried PRP-PCL scaffold group (279.75/field) was significantly higher than that of the gelatinous PRP-PCL scaffold group (167.00/field) and the bare PRP-PCL scaffold group (134.75/field) (Ff-b= 7.45, Fg-b= 1.88, P<0.01) . There was no significant difference in the migrated cells between the gelatinous PRP-PCL scaffold and bare PRP-PCL scaffold. The ALP activity of the freeze-dried PRP-PCL scaffold (ALP7 d= 12.57 U/gprot, ALP14 d= 23.20 U/gprot, ALP21 d= 58.98 U/gprot) was significantly higher than that of the gelatinous PRP-PCL scaffold (ALP7 d= 6.65 U/gprot, ALP14 d= 13.35 U/gprot, ALP21 d= 47.83 U/gprot) and the bare PCL scaffold (ALP7 d= 5.93 U/gprot、ALP14 d= 15.56 U/gprot、ALP21 d= 53.74 U/gprot) on 7, 14 and 21 d (F7 d= 3.20, P7 d<0.01; F14 d= 5.34, P14 d<0.01; F21 d= 6.04, P21 d<0.01) (F7 d= 3.60, P7 d= 0.04; F14 d= 4.14, P14 d<0.01; F21 d= 2.84, P21 d= 0.01) . However, no statistically significant difference was found in the ALP activity between the gelatinous PRP-PCL scaffold and the bare PCL scaffold except for that on 21 d. Except for the expression of OCN by DPSCs on the gelatinous PRP-PCL scaffold on 14 d, the expression of RUNX2 and OCN by DPSCs on freeze-dried PRP-PCL scaffold (OCN7 d= 4.67, RUNX27 d= 2.32, RUNX214 d= 5.88) and gelatinous PRP-PCL scaffold (OCN7 d= 2.60, RUNX27 d= 2.23, RUNX214 d= 4.67) on 7 and 14 d were significantly higher than that on the bare scaffold (OCN7 d= 1.00, RUNX27 d= 1.00, RUNX214 d= 1.00) (F7 d= 11.1, P7 d<0.01; F7 d= 3.20, P7 d= 0.04; F14 d= 11.80, P14 d<0.01) . The expression of OCN on7 d and RUNX2 on 14 d on the freeze-dried PRP-PCL scaffold (OCN7 d= 4.67) was significantly higher than that of gelatinous PRP-PCL scaffold (OCN7 d= 2.60, F= 6.26, P<0.01) . However, no statistical significance was found in the expression of OCN on 14 d between the freeze-dried PRP-PCL scaffolds and the gelatinous PRP-PCL scaffolds. Conclusion The freeze-dried PRP-PCL scaffolds were more favorable for the adhesion, proliferation and differentiation of DPCs compared with the gelatinous PRP-PCL scaffolds. Key words: Platelet-rich plasma; Printing, Three-Dimensional; Polycaprolactone; Tissue scaffold; Dental pulp cells; Biological functions