HK Inhibits Angiogenesis/Peritoneal Dissemination Figure 4. Effect of honokiol on angiogenesis. (A) Chorioallantoic membrane assay (CAM assay) was performed. Neovascular formation entrapped in type I collagen gels with or without honokiol (HK, 20 mM) treatment was examined. After 24-h incubation, the area around the loaded disk was photographed. (B) Matrigel (0.6 ml) was implanted subcutaneously in nude mice with or without honokiol (10 mg/ml) or VEGF (100 ng/ml). The injected matrigel rapidly formed a single solid gel plug. After 21 days, mice were sacrificed and matrigel plugs were excised. Representative matrigel plugs (a) and IHC for CD31 staining of sections from matrigel plugs (b) are shown. Quantifications of vessel numbers (c) and endothelial cells (d) in matrigel plug sections (counts/field) were calculated. The numbers in each case are the average from five different slides and five regions per slide. All data are presented as mean 6 SEM (n = 8–10). *p,0.05 as compared with control. doi:10.1371/journal.pone.0043711.g004 PLOS ONE | www.plosone.org 6 August 2012 | Volume 7 | Issue 8 | e43711