Figure 2.

(See previous page). Bafilomycin A₁ promotes differentiation, elevates cell death and decreases chondrocyte proliferation in cultured metatarsal bones. Histological appearance of different zones of the growth plate of cultured bones showed increased hypertrophy upon Baf exposure (A). Baf caused an increase in phosphorylated RPS6 (B) and SQSTM1 accumulation (C) in chondrocytes when assessed by immunohistochemistry. Visualization of proteoglycan levels by Safranin O staining did not reveal any changes (D). Treatment with Baf elevated cell death as assessed by TUNEL labeling (E) and decreased cell proliferation as assessed by BrdU incorporation (F). Baf stimulated an increase in Col10a1 levels as assessed by in situ hybridization (G) and immunohistochemistry (H). Levels of mineralization were assessed by Von Kossa staining and showed no obvious differences (I). Osteoclasts were visualized by ACP5 staining and no changes were observed (J). All bones were exposed to Baf for 3 d. Scale bar: 100 μm. Statistical analysis is incorporated in the text.