IL1B and cyclic hematopoiesis: Furthermore, osteoarthritic chondrocytes (OA-CH) were stimulated with interleukin 1β (IL-1β) to establish a standardized in vitro OA model; the relationship between IL-1β and diagnostic biomarkers [collagen type 3 alpha 1 chain (COL3A1) and matrix metalloproteinase 9 (MMP9)] was determined by quantitative reverse transcription PCR (qRT-PCR) and Western blotting.