Impact of storage conditions on electromechanical, histological and histochemical properties of osteochondral allografts.
BACKGROUND
Osteochondral allograft transplantation has a good clinical outcome, however, there is still debate on optimization of allograft storage protocol. Storage temperature and nutrient medium composition are the most critical factors for sustained biological activity of grafts before implantation. In this study, we performed a time-dependent in vitro experiment to investigate the effect of various storage conditions on electromechanical, histological and histochemical properties of articular cartilage.


METHODS
Osteochondral grafts derived from goat femoral condyles were frozen at -70 °C or stored at 4 °C and 37 °C in the medium supplemented with or without insulin-like growth factor-1 (IGF-1). After 14 and 28 days the cartilage samples were quantitatively analysed for electromechanical properties, glycosaminoglycan distribution, histological structure, chondrocyte viability and apoptosis. The results were compared between the experimental groups and correlations among different evaluation methods were determined.


RESULTS
Storage at -70 °C and 37 °C significantly deteriorated cartilage electromechanical, histological and histochemical properties. Storage at 4 °C maintained the electromechanical quantitative parameter (QP) and glycosaminoglycan expression near the normal levels for 14 days. Although hypothermic storage revealed reduced chondrocyte viability and increased apoptosis, these parameters were superior compared with the storage at -70 °C and 37 °C. IGF-1 supplementation improved the electromechanical QP, chondrocyte viability and histological properties at 37 °C, but the effect lasted only 14 days. Electromechanical properties correlated with the histological grading score (r = 0.673, p < 0.001), chondrocyte viability (r = -0.654, p < 0.001) and apoptosis (r = 0.416, p < 0.02). In addition, apoptosis correlated with glycosaminoglycan distribution (r = -0.644, p < 0.001) and the histological grading score (r = 0.493, p = 0.006).


CONCLUSIONS
Our results indicate that quality of allografts is better preserved at currently established 4 °C storage temperature. Storage at -70 °C or at 37 °C is unable to maintain cartilage function and metabolic activity. IGF-1 supplementation at 37 °C can enhance chondrocyte viability and improve electromechanical and histological properties of the cartilage, but the impact persists only 14 days. The correlations between cartilage electromechanical quantitative parameter (QP) and metabolic activity were detected. Our findings indicate that non-destructive assessment of cartilage by Arthro-BST is a simple and reliable method to evaluate allograft quality, and could be routinely used before implantation.
Department of Orthopaedics and Traumatology, Hospital of Lithuanian University of Health Sciences Kaunas Clinics, Kaunas, Lithuania.
Tomas
T
Mickevicius
Pathology Center, Department of Infectious Diseases, Veterinary Academy, Lithuanian University of Health Sciences, Kaunas, Lithuania.
Alius
A
Pockevicius
Large Animal Clinic, Veterinary Academy, Lithuanian University of Health Sciences, Kaunas, Lithuania.
Audrius
A
Kucinskas
Department of Orthopaedics and Traumatology, Hospital of Lithuanian University of Health Sciences Kaunas Clinics, Kaunas, Lithuania.|Institute of Sports, Lithuanian University of Health Sciences, Kaunas, Lithuania.
Rimtautas
R
Gudas
Department of Orthopaedics and Traumatology, Hospital of Lithuanian University of Health Sciences Kaunas Clinics, Kaunas, Lithuania.|Institute of Sports, Lithuanian University of Health Sciences, Kaunas, Lithuania.
Justinas
J
Maciulaitis
Institute of Physiology and Pharmacology, Lithuanian University of Health Sciences, Kaunas, Lithuania.
Aurelija
A
Noreikaite
Institute of Physiology and Pharmacology, Lithuanian University of Health Sciences, Kaunas, Lithuania. arvydas.usas@lsmuni.lt.
Arvydas
A
Usas
D064591:Allografts; D000818:Animals; D017209:Apoptosis; D002358:Cartilage, Articular / Q000033:anatomy & histology*; D002470:Cell Survival; D019902:Chondrocytes / Q000502:physiology*; D015925:Cryopreservation; D005269:Femur; D006041:Goats; D007334:Insulin-Like Growth Factor I; D010619:Phenazines
D010619:Phenazines; D007334:Insulin-Like Growth Factor I; C009195:safranine T