OBJECTIVETo investigate the apoptosis-related mechanisms of levenorgestrel-releasing intrauterine system (LNG-IUS), oral medroxyprogesterone (MPA), and injective gonadotrophic hormone releasing hormone agonist (GnRHa) on eutopic endometrium of patients with endometriosis. Methods We collected the samples of endometrium from patients with endometriosis before operation and after insertion of LNG-IUS, administration of oral MPA, or injection of GnRHa. The ultrastructure of endometria was observed and compared by electron microscopy. Apoptotic cells were assessed by the terminal deoxynucleotidyl transferase-mediated deoxy-UTP nick-end labeling (TUNEL) assay, and the expressions of Bax, Fas, and Fas-L mRNA were determined by semi-quantitative reverse transcription-polymerase chain raction. Results After have been exposured to LNG-IUS, the apoptotic rate of endometrial epithelial cells and stromal cells increased from (24. 4 +/- 35.0)% to (51.0 +/- 37.8)% (P = 0.027) and (35.3 +/- 30.2)% to (76.4 +/- 11.2)% (P = 0.008), respectively. The degree of apoptosis under transmission electron microscopy was in an order of GnRHa > LNG-IUS > MPA. The expression of Fas-L mRNA in eutopic endometrium of patients with endometriosis was significantly higher than that of the normal control (P < 0.05). The expressions of three apoptosis-related proteins had no significant difference.

CONCLUSIONMedical treatments can increase the apoptosis of eutopic endometrial cells, and such effect was strongest in GnRHa and relatively weaker in LNG-IUS and MPA.