Matrigel plugs containing PBS, ATDC5 CM, IL-1β-treated ATDC5 CM or IL-1β-treated CM with FGF-2 NAb were subcutaneously injected into nude mice. After 7 days, the plugs were retrieved and photographed. Scale bar, 1 cm (A; n=6). Haemoglobin levels were quantified and normalized to the PBS group (B; n=6). Paraffin sections of Matrigel plugs were stained with CD31 by IHC staining and photographed under a microscope. Scale bar, 50 μm (C; n=5). The CAM assay utilized 5-day-old fertilized chick embryos. Matrigel was mixed with PBS, ATDC5 CM (Con), IL-1β-treated ATDC5 CM and IL-1β-treated ATDC5 CM with FGF-2 NAb, and then placed on to the CAMs for 3 days. The CAMs were then examined by microscopy and photographed. Scale bar, 5 mm (D; n=6). Vessels on the CAMs were quantified (E; n=6). VEGF was used as a positive control in (D) and (E). Quantification results are expressed as means±S.D. *P<0.05 compared with the PBS group; #P<0.05 compared with the IL-1β-treated CM group in (B) and (E).