Does TGF-beta protect articular cartilage in vivo?

: Repeated intraarticular injections of transforming growth factor beta cause stimulation of articular cartilage proteoglycan synthesis, influx of inflammatory cells, fibrosis and osteophyte formation. When injected together with interleukin-1, TGF-beta enhances IL-1 induced cell-attraction in a synergistic way, while it counteracts IL-1 induced suppression of cartilage PG synthesis.