Objective/Hypothesis: A recent clinical study of the human lactoferrin peptide PXL01 in sodium hyaluronate (HA) administrated around repaired tendons in the hand showed significantly improved digit mobility compared with placebo. To investigate the antiadhesive mechanisms of PXL01 in HA, we have used the rabbit lactoferrin peptide, rabPXL01 in HA, in a rabbit model of healing tendons and tendon sheaths. Materials and Methods: On days 1, 3, and 6 after tendon injury and surgical repair, reverse transcription-quantitative PCR (RT-qPCR) was used to assess messenger RNA (mRNA) expression levels for genes encoding the mucinous glycoprotein PRG4 (also called lubricin), and a subset of matrix proteins, cytokines, and growth factors involved in flexor tendon repair. RabPXL01 in HA was administrated locally around the repaired tendons, and the mRNA expression was compared with untreated repaired tendons and tendon sheaths using analysis of variance. Results: We observed, at all time points, significantly increased expression of PRG4 mRNA in tendons treated with rabPXL01 in HA, but not in tendon sheaths. In addition, treatment with rabPXL01 in HA lead to repression of the mRNA levels for the proinflammatory mediators interleukin IL-1β, IL-6, and IL-8 in tendon sheaths. Conclusions: These findings suggest that rabPXL01 in HA increases lubricin production while diminishing inflammation, which correspondingly reduces the gliding resistance and inhibits adhesion formation after flexor tendon repair.
