The role of c-jun protein in proliferation and apoptosis of the endometrium throughout the menstrual cycle.

Proliferation and apoptosis of the endometrium throughout the menstrual cycle were evaluated. Sections from 30 premenopausal women were examined using antibodies of c-jun protein, c-fos protein, estrogen receptors alpha and beta (ER-alpha and ER-beta), progesterone receptor (PR), and Ki-67. Apoptotic cells were identified using a modified terminal deoxynucleotidyl-transferase-mediated biotinylated deoxyuridine triphosphate nick-end labeling (TUNEL) method. The cyclic changes of c-jun protein, c-fos protein, ER-alpha, PR, and Ki-67 were shown in glandular epithelial cells. Although the stromal expression of ER-alpha decreased during the secretory phase, a high stromal expression of c-jun protein and PR was still observed during the late secretory phase. The expression of ER-beta appeared lower as compared with that of ER-alpha, without a cyclic change. The apoptotic index was significantly elevated in the glandular epithelial cells of the late secretory phase, whereas a few apoptotic cells were detected in the stromal cells at any stage of the cycle. The cyclic change of c-jun protein probably plays an important role in proliferation and apoptosis of glandular epithelial cells. The persistent stromal expression of c-jun protein and PR is thus considered to prevent stromal cells from entering into apoptosis during the late secretory phase. Copyright 2004 S. Karger AG, Basel