Metabolic and cytoprotective effects of in vivo peri-patellar hyaluronic acid injections in cultured tenocytes

Abstract

The purpose of this study was to investigate tenocyte mechanobiology after sudden-detraining and to examine the hypothesis that repeated peri-patellar injections of hyaluronic acid (HA) on detrained patellar tendon (PT) may reduce and limit detrained-associated damage in tenoctyes.

Twenty-four male Sprague–Dawley rats were divided into three groups: Untrained, Trained and Detrained. In the Detrained rats, the left tendon was untreated while the right tendon received repeated peri-patellar injections of either HA or saline (NaCl). Tenocyte morphology, metabolism and synthesis of C-terminal-propeptide of type I collagen, collagen-III, fibronectin, aggrecan, tenascin-c, interleukin-1β, matrix-metalloproteinase-1 and-3 were evaluated after 1, 3, 7 and 10 days of culture. Transmission-electronic-microscopy showed a significant increase in mitochondria and rough endoplasmic reticulum in cultured tenocytes from Detrained-HA with respect to those from Detrained-NaCl. Additionally, Detrained-HA cultures showed a significantly higher proliferation rate and viability, and increased synthesis of C-terminal-Propeptide of type I collagen, fibronectin, aggrecan, tenascin-c and matrix-metalloproteinase-3 with respect to Detrained-NaCl ones, whereas synthesis of matrix-metalloproteinase-1 and interleukin-1β was decreased. Our study demonstrates that discontinuing training activity in the short-term alters tenocyte synthetic and metabolic activity and that repeated peri-patellar infiltrations of HA during detraining allow the maintenance of tenocyte anabolic activity.

• Detraining
• hyaluronic acid
• patellar tendon
• rats
• tenocytes

Declaration of interest

The authors of the Laboratory of Biocompatibility, Technological Innovations and Advanced Therapies-Department RIT Rizzoli-Rizzoli Orthopaedic Institute, Bologna, Italy and of the Laboratory of Preclinical and Surgical Studies, Rizzoli Orthopaedic Institute, Bologna, Italy have received funding from Fidia Farmaceutici S.p.A. (Via Ponte della Fabbrica 3/A, 35031 Abano Terme (PD), Italy) for providing hyaluronic acid, costs of animals, animal housing and analyses (Contract Number-3047, 29 November 2010).

This research was supported by Fidia Farmaceutici S.p.A, by Rizzoli Orthopaedic Institute grant “Ricerca Corrente” and Regione Emilia Romagna.