Figure 2. BrdU labeling of growth plate chondrocytes. Representative photomicrographs of chondrocyte proliferation labeled with bromodeoxyuridine (BrdU) in the proliferating zones of the cranial base cartilage (CBC). (A) Negative control (no BrdU antibody). (B,C,D) Samples treated with BrdU antibodies. B, sham control; C, static force; D, cyclic force. There are marked increases in BrdU-labeled proliferating chondrocytes in association with cyclic force (D), in comparison with natural chondral growth (B) and static force (C). Arrows indicate the nuclei of proliferating chondrocytes. Scale bar: 40 µm.