Multiple mechanisms are involved in apoptotic cell death in the mouse uterus and vagina after ovariectomy.

摘要

Withdrawal of sex hormones by gonadectomy results in rapid involution of mouse reproductive organs. To study the regression mechanism in the uterus and vagina after ovariectomy, histologic and biochemical changes were examined. Apoptotic cells were detected by in situ 3'-DNA nick end labeling method and electron microscopy, while the number of cells showing incorporation of bromo-deoxyuridine (BrdU) decreased in the uterus and vagina after ovariectomy. DNA fragmentation in the uterus was observed even at estrus and the degree of fragmentation increased after ovariectomy. DNA fragmentation in the vagina occurred 1-5 days after ovariectomy. Semi-quantitative RT-PCR revealed that expression of Fas-ligand and tumor necrosis factor-alpha (TNF-alpha) mRNA in the uterus and vagina was increased by ovariectomy. These results suggest that apoptotic cell death is induced by ovariectomy through the mediation of both Fas and TNF-alpha in the mouse uterus and vagina; however, uterine and vaginal cells in CBA lpr(cg)/lpr(cg) mice lacking functional Fas showed apoptosis, indicating that Fas is not the sole regulator of apoptosis in female reproductive organs in mice.