Effects of IGF1 on the proliferation and cell cycle of antler chondrocytes. (A) In situ hybridization of IGF1 expression in the cartilage of sika deer antler. Bar = 60μm. (B) Effects of IGF1 on the proliferation of antler chondrocytes. After antler chondrocytes were treated with rIGF1, or both rIGF1 and PQ401 for 24 h, MTS assay was performed. Data are shown mean ± SEM. *P < 0.05. (C and D), Effects of IGF1 on the cell cycle of antler chondrocytes. After antler chondrocytes were treated with rIGF1, or both rIGF1 and PQ401 for 24 h, flow cytometry was performed.