Background: The aim of this study was to analyze possible interactions of different xenogeneic collagen membranes (CM) and platelet-rich fibrin (PRF). PH values were evaluated in the CM rehydration process with PRF, and their influence on angiogenesis was analyzed in vivo. Materials and Methods: Porcine (Bio-Gide®, Geistlich)- and bovine-derived collagen membranes (Symbios®, Dentsply Sirona) were biofunctionalized with PRF by plotting process. PRF in comparison to blood, saline and a puffer pH7 solution was analysed for pH-value changes in CM rehydration process in vitro. The yolk sac membrane (YSM) model was used to investigate pro-angiogenic effects of the combination of PRF and the respective CM in comparison to native pendant by vessel in-growth and branching points after 24, 48 and 72 h evaluated light-microscopically and by immunohistochemical staining (CD105, αSMA) in vivo. Results: Significantly higher pH values were found at all points in time in PRF alone and its combined variants with Bio-Gide® and Symbios® compared with pure native saline solution and pH 7 solution, as well as saline with Symbios® and Bio-Gide® (each p < 0.01). In the YSM, vessel number and branching points showed no significant differences at 24 and 48 h between all groups (each p > 0.05). For PRF alone, a significantly increased vessel number and branching points between 24 and 48 h (each p < 0.05) and between 24 and 72 h (each p < 0.05) was shown. After 72 h, CM in combination with PRF induced a statistically significant addition to vessels and branching points in comparison with native YSM (p < 0.01) but not vs. its native pendants (p > 0.05). Summary: PRF represents a promising alternative for CM rehydration to enhance CM vascularization.
Keywords: angiogenesis; collagen matrix; guided bone regeneration; in ovo yolk sac; pH value; platelet-rich fibrin.