Fig. 7

Triple immunohistochemical images for SMA, vimentin, and desmin in the bovine CL. In the CL during the late-luteal (LL) stage, the tunica media of arteries and arterioles of various sizes are immunoreactive for all three markers (asterisks and arrows in a–d). A specific number of SMA-positive cells distributed in the CL parenchyma contain vimentin (inserts in a–d), suggesting that they are resident fibroblasts. The tunica media of the artery contains desmin, a smooth muscle-specific intermediate filament, while immunoreactivities for SMA and vimentin are localized in the tunica media and cells loosely surrounding it (asterisks in e–h). In the early regressing CL, the walls of the arteries (asterisks in i– l) and crooked arterioles (arrows in i–l) abundantly contain both SMA and desmin, whereas the vimentin immunoreaction is strong outside the vessels (i–l). In the fully regressed CL, the thick walls of arteries (asterisks in m–p) and crooked vessels consist of SMA and desmin double-positive epithelioid cells. e–h is a closer view of the areas enclosed by squares in (a–d)