Figure 4

B[a]P inhibits chondrogenesis and chondrocyte differentiation. (A) Representative sections of mandibular cartilage from WT and AhR^−/− mice treated with or without B[a]P (+ , oral gavage, 120 mg/kg) which were stained with hematoxylin and eosin (HE), Safranin O and also subjected to aggrecan and Col2a1 IHC staining. Scale bar = 300 μm. (B) Area of proteoglycan staining in mandibular condyle cartilage from WT and AhR^−/− mice treated with corn oil only or B[a]P by oral gavage. (C–E) Numbers of cells expressing aggrecan (C), Col2a1 (D), or Sox9 (E) were counted in the posterior thirds or central of the mandibular condylar cartilages obtained from AhR^−/− and WT control mice treated with B[a]P were compared. (F–H) Following oral administrations of AhR ligand B[a]P (120 mg/kg) to WT and AhR^−/− mice, mRNA levels of aggrecan (F), Col2a1 (G), and Sox9 (H) were detected by real-time PCR. **p < 0.01.