Relationship between the migratory, metabolic and proliferative ability of fibrochondrocytes and the meniscal fragment size: an in vivo study

Objective To investigate the migratory, metabolic and proliferative ability of rabbit fibrochondrocytes in meniscal fragments of different sizes under an in vivo subcutaneous environment. Methods Adult, male, New Zealand white rabbit menisci were harvested and the inner two-thirds of each were minced into different sizes: 0.5 × 0.5 × 0.5 mm (group A); 1.0 × 1.0 × 1.0 mm (group B); 2.0 × 2.0 × 2.0 mm (group C). Meniscal fragments were packed into a fascia sheath, then implanted subcutaneously. At weeks 1, 2 and 3 postimplantation, meniscal fragments were harvested; cell migration and viability were then evaluated by confocal laser scanning microscopy and haematoxylin and eosin staining. Aggrecan was detected using Safranin O and Fast Green staining, and protein levels of types I and II collagen, and proliferating cell nuclear antigen (PCNA), were evaluated by immunohistochemistry. Results Protein levels of types I and II collagen and PCNA, and fibrochondrocyte migration, were highest in group A compared with groups B and C, but aggrecan staining remained the same across the groups. Conclusion There was an inverse relationship between the migratory, metabolic and proliferative abilities of rabbit fibrochondrocytes and meniscal fragment size.