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[Differential behaviour of human adult arthrotic chondrocytes under 2D- and 3D-cultivation set-ups in a collagen I gel].

AIM
The aim of this study was to assess the influence of culture conditions on the differentiation of human chondrocytes expanded in monolayer (2 D) or a three-dimensional (3 D) biodegradable collagen type I matrix, with regard to chondrocyte-specific markers.


METHOD
Human arthrotic chondrocytes were taken from nine adult donors (average age 72.1 years) undergoing knee replacement. The isolated cell suspensions were split and cultivated either in a 3-dimensional collagen gel (3 D) or in a monolayer (2 D). The amounts of mRNA for collagen I and II, aggrecan and melanoma inhibitory activity (MIA) were quantified by means of real-time PCR at different times.


RESULTS
The 2 D-passaged cells showed a significant increase of collagen I between P 00 and P 01 (p = 0.009), whereas the expression of collagen II decreased significantly (p = 0.022). There was no significant change for collagen I in 3 D-cultivation, whereas the collagen II expression decreased significantly after 2 to 4 weeks (p = 0.001).


CONCLUSION
Human adult chondrocytes obtained from elderly patients showed a decreased expression of collagen II with increased passaging in the monolayer (2 D). The decrease was delayed in 3 D-cultivation. We thus question the assumption that the dedifferentiation of chondrocytes can be prevented or reversed by 3 D-cultivation. Based on our results, we recommend the use of freshly isolated and therefore sparsely dedifferentiated chondrocytes for transplantation.