Effects of intermediate filament cytoskeleton on the matrix anabolism of rabbit articular chondrocytes in vitro

Abstract

Objective To investigate the effects of disruption of intermediate filament cytoskeleton on the matrix anabolism of rabbit articular chondrocytes in vitro. Methods One-month-old New Zealand rabbits were killed and their knee joints were taken out under the aseptic condition. The chondrocytes were isolated by enzymolysis method and inoculated into a 6-well plate. The medium was abandoned after cell attachment and the cells were divided into two groups randomly. The cells in control group were cultured with DMEM/F12,while those in intermediate filament disruption group (IF disruption group) cultured in the media containing 5 mmol/L acrylamide. The glycosaminoglycan (GAG) content was determined by Alician Blue method,and the hydroxyproline content was measured to estimate collagen synthesis in the supernatant when medium was changed after 4 and 7 days. Results There was no significant difference in GAG content in the supernatant between the two groups with medium change after 4 and 7 days (P>0. 05). The GAG content in the two groups were all significantly increased with the culture time (P 0. 05), but significantly decreased at the 7th day as compared with the control group (P 0.05 ). There was no significant change in the hydroxyproline content in the supernatant of IF disruption group between the 7 th day and 4th day. Conclusion The GAG synthesis of chondrocytes has time cumulative effect,however,disruption of intermediate filament has no effect on the GAG synthesis. The disruption of the intermediate filament can decrease the collagen synthesis of chondrocytes in vitro, suggesting that the intermediate filament is necessary for the collagen synthesis of articular chondrocytes. Key words: Chondrocyte; Cytoskeleton; Intermediate filament; Collagen