Figure 4.

Proliferation (BrdUrd incorporation) and apoptosis (TUNEL staining) in 4-week TGF-β arteries. (A) Proliferating cells (arrowheads and elsewhere) are confined to upper intima. No proliferation is detected in chondrocytic portions of intima or media. (B) Low-power view shows TUNEL-positive nuclei (red dots) confined to the area of cartilaginous metaplasia (box). (C) High-power view shows widespread pyknosis and occasional chromatin margination (arrowheads). Arrows in A and C indicate internal elastic lamina. TUNEL stains of β-gal arteries (not shown) appeared essentially as the top (unboxed) area of B. Original magnifications: (A and C) ×65; (B) ×20.