engleski

Ultrastructural analysis of sheep articular and nasal septum cartilage harvested for osteochondral tissue engineering in bioreactor

Objectives The purpose of this study was to analyse ultra structural features of the articular and nasal septum cartilage harvested from sheep. The nasal septum cartilage could be a promising alternative source of chondrocytes for cartilage tissue engineering in orthopedics. Methods Cartilage samples from both knee femoral condyle and nasal septum were harvested from 3 healthy sheep under general anaesthesia and immediately immersed in 4% buffered paraformalydehyde (PFA) for light microscopy and in 2, 5% buffered glutaraldehyde (GA) for transmission electron microscopy (TEM) (samples from 1 sheep). Samples were then embedded in paraffin or Durcopan resin respectively, sectioned and stained or contrasted. For histology analysis, 5 µm thick sections were stained with hematoxylin-eosin (HE), Safranin O and Picrosirius Red. Immunofluorescence (IF) was performed against collagen type II. Semi-thin sections (1 µm) were stained with toluidine blue. Results HE, Safranin O and Picrosirius Red staining revealed similar morphology of the cartilage originating from the two locations. Although the nasal septum cartilage lacks mineralized zone and hypertrophic chondrocytes, in the area close to perichondrium chondrocytes are less rounded, more flattened, similar to chondrocytes of a superficial zone in the articular cartilage. Safranin O staining was more intensive in territrorium of the nasal cartilage compared to the articular cartilage indicating higher content of glycosaminoglycans (GAGs). Picrosirius Red and IF showed that matrix of both cartilages contains thin, collagen type II fibrils. Ultra-thin sections on TEM revealed the difference in extracellular matrix between these two cartilages. Volume density of collagen fibrils in the articular cartilage was 55% compared to 10% in nasal cartilage. Cell count was similar in both cartilages but cell number varies greatly in the articular cartilage (40.19±9.5 versus 36, 6±22, 6 cells/microscopic field). Conclusions This study demonstrated hyaline nature of the nasal septum cartilage. There are some fine differences in the morphology between these two cartilages but high GAG content, collagen II and abundance of chondrocytes makes nasal septum cartilage a fine candidate for tissue engineering experiments in sheep.

articular cartilage ; nasal septum ; tissue engineering

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