Platelet-rich plasma induces annulus fibrosus cell proliferation and matrix production

Purpose Platelet-rich plasma (PRP) contains growth factors and creates a 3D structure upon clotting; PRP or platelet lysate (PL) might be considered for annulus fibrosus (AF) repair. Methods Bovine AF cells were cultured with 25 % PRP, 50 % PRP, 25 % PL, 50 % PL, or 10 % FBS. After 2 and 4 days, DNA, glycosaminoglycan (GAG), and mRNA levels were analyzed. Histology was performed after injection of PRP into an AF defect in a whole disc ex vivo. Results By day 4, significant increases in DNA content were observed in all treatment groups. All groups also showed elevated GAG synthesis, with highest amounts at 50 % PL. Collagen I and II expression was similar between groups; aggrecan, decorin, and versican expression was highest at 25 % PL. Injection of PRP into the AF defect resulted in an increased matrix synthesis. Conclusions Platelet-rich preparations increased the matrix production and cell number and may therefore be considered to promote AF repair.