Cycle dependent expression of endometrial metallothionein.

OBJECTIVES Molecular changes observed in endometrium with respect to menstrual cycle changes seem to be crucial for the reproductive function. Accumulation of cytotoxic cells increases the exposure of endometrial cells to apoptosis. Protection against apoptosis may be reached by endometrial cells by self molecular regulation. Metallothionein was suggested to participate in this process. The aim of our study was to evaluate endometrial MT immunoreactivity with respect to the menstrual cycle phases. MATERIALS AND METHODS MT expression was assessed using immunohistochemistry method in 47 endometrial tissue samples derived from randomly selected patients with respect to the menstrual cycle phases--proliferative and secretory with distinguishing early, mid and late subphases in each. RESULTS MT expression changes were observed respectively to hormonal fluctuations with the highest level during mid secretory phase and its respective decrease during the early, late secretory and mid proliferative menstrual cycle phases. The lowest MT immunoreactivity level was disclosed during early proliferative phase. CONCLUSION Significant differences in MT expression observed in endometrium with respect to menstrual cycle changes might suggest MT participation in endometrial cells protection against apoptosis.