MODULATION OF INTERLEUKIN-1 RECEPTOR EXPRESSION BY TRANSFORMING GROWTH-FACTOR-BETA IN CULTURED RABBIT ARTICULAR CHONDROCYTES - ANALYSIS BY REVERSE TRANSCRIPTION-POLYMERASE CHAIN-REACTION

Interleukin-1 receptor type I(IL-1RI) expression in cultured rabbit ar ticular chondrocytes (RAC) was studied by reverse transcription-polyme rase chain reaction (RT-PCR). A cDNA probe specific for the rabbit IL- 1RI gene was constructed using primers derived from the sequence data of the human, murine and chick receptors. Transforming growth factor-b eta 1 (TGF beta-1) was shown to transiently increase the level of expe cted 900-bp PCR product at 1 h of incubation and decrease the expressi on at 48 and 72 h with no effect at 24 h. In receptor binding assays u sing [I-125]-IL-1 alpha, TGF beta decreased IL-1R bioactivity at all t ime points. These results suggest that TGF beta-induced down-regulatio n of IL-1 RI could be responsible for its ability to antagonize the ef fect of IL-1 and that TGF beta may have a role in the repair of articu lar cartilage.