Fig 4. HIF-2α expression in the involuting mammary gland.

Inserts are enlargements of the indicated areas. Size bars: 50 μm, 40x obj was used in all micrographs. A. In the early involuting gland, the morphology resembles the lactating gland and the basement membrane is evident at this stage. B-D. As tissue remodelling proceeds during involution, the collagen layer becomes unstructured. E-H. HIF-2α-positive cells were detected at all studied stages of involution. I-L. Macrophage infiltration (F4/80 positive) was first evident at the fifth day of involution (J) and increased with time (K, L).