Effect of Polydeoxyribonucleotide on Tendon Regeneration in Tendinopathy Animal Model

Abstract

Polydeoxyribonucleotide (PDRN) is a mixture of deoxyribonucleotide polymers of different lengths and binds to the A2A receptor. PDRN has been used for the treatments of regeneration. The aim of this study was to investigate the effect of PDRN on tendon regeneration in Achilles tendinopathy. Fourty-eight Sprague-Dawley rats were used for the study. I injected type I collagenase to rat Achilles tendon to make a tendinopathy model. Four days later, I injected saline for control group, PDRN for experimental group to Achilles tendon. Following the plan, I sacrificed rats at 2 weeks or 4 weeks after the treatment and measured quantitative real-time polymerase chain reaction (qRT-PCR), western blot, histological analysis and mechanical testing. The maximal stress of 4 week PDRN group was higher than control group (p = 0.026) and the cross-sectional area decreased in the PDRN group at 4 weeks (p = 0.009). The mRNA level of collagen I, collagen III, Tenascin C, and VEGF showed no significant difference in PDRN group at both weeks. Protein level of Tenascin C significantly decreased in 4 weeks PDRN group (p = 0.009), but the protein levels of the rest tendon markers showed no significant differences. I expect the therapeutic effects of the PDRN and the maximal stress of PDRN group increased. Even though molecular biological evidences for regeneration were not enough in this study, elevated tension ability of PDRN seems to be good treatment to try. The molecular biological evidences might not be detected because the extreme inflammation phase was undergone. To clarify the mechanism of increased maximal stress and decreased cross-sectional area, further studies including the inflammatory markers should be done.