Supplementation With Platelet-Rich Plasma Improves the In Vitro Formation of Tissue-Engineered Cartilage With Enhanced Mechanical Properties

Abstract

This study aimed to determine the effects of platelet-rich plasma (PRP) on the histologic, biochemical, and biomechanical properties of tissue-engineered cartilage. Chondrocytes isolated from bovine metacarpal-phalangeal articular cartilage were seeded on top of a porous ceramic substrate (calcium polyphosphate [CPP]). Cultures were supplemented with fetal bovine serum (FBS), PRP, or platelet-poor plasma (PPP) at 5%. On day 5, the concentration was increased to 20%. PRP and PPP were obtained through centrifugation of whole blood withdrawn from a mature cow. After 2 weeks, samples (n = 8) were analyzed histologically, biochemically, and biomechanically. Data were analyzed using the Wilcoxon test (significance, P < .05). Chondrocytes cultured in 20% PRP formed thicker cartilage tissue (1.6 ± 0.2 mm) than did cells grown in 20% FBS (0.7 ± 0.008 mm; P = .002) and 20% PPP (0.8 ± 0.2 mm; P = .03). Cartilage tissue generated in the presence of 20% PRP had a greater equilibrium modulus of 38.1 ± 3.6 kPa versus 15.6 ± 1.5 kPa (P = .0002) for 20% PPP and 20.4 ± 3.5 kPa (P = .007) for 20% FBS. Glycosaminoglycan (GAG) content was increased in tissues formed in 20% PRP (176 ± 18.8 μg GAG/mg) compared with those grown in 20% FBS (112 ± 10.6 μg GAG/mg; P = .01) or 20% PPP (131.5 ± 14.8 μg GAG/mg; P = .11). Hydroxyproline content was similar whether the media was supplemented with 20% PRP (8.7 ± 0.9 μg/mg), 20% FBS (7.6 ± 0.9 μg/mg; P = .37), or 20% PPP (6.4 ± 1 μg/mg; P = .28). DNA content was similar in all tissues whether formed in 20% PRP (11.9 ± 3.5 μg/mg), 20% FBS (9.3 ± 2.5 μg/mg; P = .99), or 20% PPP (7.2 ± 1.3 μg/mg; P = .78). Immunostained samples showed prevalence of type II collagen in tissues formed in the presence of 20% PRP. The presence of PRP in the culture media enhances the in vitro formation of cartilage, with increased GAG content and greater compressive mechanical properties, while maintaining characteristics of hyaline phenotype. Understanding the in vitro effects of PRP on tissue-engineered cartilage may lead to the creation of engineered cartilage tissue with enhanced properties suitable for cartilage repair.