Cytokeratin expression in bovine corpora lutea

Abstract

Cytokeratin (CK)-positive cells were obtained from bovine corpora lutea. When cultured, these cells behave like CK-positive endothelial cells obtained from bovine large blood vessels. The origin of CK-positive cells has now been studied in 45 bovine corpora lutea of different estrous cycle stages. Additionally, 7 corpora lutea of pregnant cows were examined. The tissues were grouped into early stage (days 2 to 4), secretory stage (days 5 to 17) and late stage (days 18 to 21) according to gross morphology, wet weight and total progesterone content. One portion of a corpus luteum was used for immunohistochemistry, and another for Western blot analysis. Twenty-six of the 45 corpora lutea showed CK expression, as confirmed by immunostaining and Western blotting. Cytokeratin expression was found in all corpora lutea from the early stage, in 14 of 26 corpora lutea from the secretory stage, and 3 of 10 from the late stage. Early stage corpora lutea displayed "zonation" such that a high number of CK-positive luteal cells occurred in the region of the previous granulosa layer and a very low number in the previous thecal layer. Secretory CK-positive corpora lutea showed uniformly distributed, predominantly large luteal cells. In secretory corpora lutea of group A, CK-positive cells and a distinct microvascular tree were seen, the latter visualized by factor VIII-related antigen immunolabelling of endothelial cells. Group B showed none or very few CK-positive cells. Corpora lutea of pregnant cows behaved like corpora lutea of group B. Roughly 1% of CK-positive cells closely associated with the capillary wall were sometimes reminiscent of endothelial cell sprouts.

TGFB1 disrupts the angiogenic potential of microvascular endothelial cells of the corpus luteum

“…1B). Purified CLENDO cells did not express cytokeratin 18, consistent with previous reports that demonstrated that the majority of luteal microvascular endothelial cells do not express cytokeratin 18 (Ricken et al, 1995;Tscheudschilsuren et al, 2002) (Fig. 1B).…”

“…The bovine corpus luteum contains multiple endothelial cell populations that differ in their morphology, cytoskeleton proteins and expression of cell adhesion proteins (reviewed in Davis et al, 2003). The CLENDO cells used in the present study, which are cytokeratin negative and VE-cadherin positive, presumptively represent the majority of luteal microvascular endothelial cells (Ricken et al, 1995;Shirasuna et al, 2007;Tscheudschilsuren et al, 2002). It is possible that, as in the examples cited above, subpopulations of luteal endothelial cells respond to TGFB1 in a manner different from that of our CLENDO cells.…”

KIT receptor-positive cells in the bovine corpus luteum are primarily theca-derived small luteal cells

“…Cyclic CL stages were classified at the macroscopical level according to Ireland et al (1980). Development, early and late secretory stage, and early regression were finally confirmed by immunostaining for factor VIII-related antigen (FVIIIr) to reveal differences in the microvascular bed (Ricken et al 1995). For collection of CL during pregnancy, uterine horns were opened and the fetus removed for measurement of the crown-rump length (Sakumoto et al 2000): trimester I, fetal crown-rump length 6-20 cm; trimester II, 25-45 cm; and trimester III, 50-80 cm.…”

Microvascular Endothelial Cells Differ in Their Basal and Tumour Necrosis Factor-α-Regulated Expression of Adhesion Molecules and Cytokines

“…These CK-positive (CK+) MVEC are morphologically different from the common CK-negative (CK–) MVEC obtained from the same microvascular bed [5, 6, 7]. As we have already shown, CK+ EC isolated from corpus luteum microvessels behave morphologically like CK+ EC from the aorta [5].…”