Immunological study of serial sections: a: Type II Collagen immunolabellingcountre stained with h&e: Slide 69: Type II collagen had the same pattern of ALP activity of nodule showing prehypertrophic chondrocytes in nonmineralized zone. b: Type I collagen Immunolabelling countre stained with h&e: Slide 72; Type I collagen expression encercled the mineralized nodule. c: Type X collagen immunolabelling countre stained with h&e:Slide 73: Type X collagen was expressed by most of cells and distributed in their matrix. d: OCN Immunolabelling countre stained with h&e: Slide 64: OCN was expressed by hypertrophic chondrocytes. e: OCN immunolabelling counter stained with h&e: Activated osteoblasts (OB) and woven bone (W) are strongly labelled. Some capillaries (C) near by these areas express osteocaline too. f: VEGF immunolabelling counter stained with h&e: VEGF was expressed by some hypertrophic chondrocytes (H). Activated and non activated osteoblasts-like cells (OB) lining the cartilage express also VEGF. Inset: Clustered and isolated cells in the matrix, surrounding hypertrophic chondrocytes, which could be destinated to capillary or osteoblast formation, are also labelled by VEGF.