Experimental Study Of Effects Of COX-2 Inhibitors On The Cells Of Endometriosis Cultured In Vitro

Objectives 1.To explore the influence of COX-2 inhibitors on the endometriotic stromal cells cultured in vitro;2.To explore the mechanism of inhibitory influence of COX-2 inhibitors on the endometriotic stromal cells;3.To evaluate the practical value of COX-2 inhibitor in treating endometriosis.Methods Endometriotic tissue was picked from 12 patients of EMs from March 2006 to January 2007 who underwent surgery in our department,and all of them were confirmed endometriosis by histology examination.We used 25 normal dendometrium picked from patients who underwent diagnostic curettage and laparoscopy.All the endometrium were divided into two groups.one group was fixed by immersion in 10%buffered formalin for 6-24h,embedded in paraffin and sectioned at 6 mm,and mounted on silane-coated slides.Expression of COX-2 were examined immumohistochemically.Endometriotic stromal cells were isolated and cultured in the absence and in the presence of serum and with or without celecoxib or nimesulide.PGE₂ and apoptosis rates were detected by EIA and flowcytometry.Main Results1.Expression of COX-2 measurement by immunohistochemistryThe expression of COX-2 in EMs group was significantly higher than that of the control group(P＜0.05).2.MTT detectionBoth selective COX-2 inhibitors,celecoxib and nimesulide,could inhibit the proliferation of ectopic stromal cells cultured in vitro in a time and dose dependent mode.3.Detection of PGE₂ levelBoth selective COX-2 inhibitors,celecoxib and nimesulide,could decrease the level of PGE₂,which were produced by ectopic stromal cells cultured in vitro in a time and dose dependent mode。4.Assessment of apoptosis by flow cytometryThe rate of apoptosis was significantly higher than that of control group after incubated with celecoxib or nimesulide in a time and dose dependent mode(P＜0.05)。5.Analysis of cell cycle by flow cytometryThe effect of cox-2 inhibitors on the cell cycle of the ectopic stromal cells was determined by flowcytometry.Ectopic stromal cells cultured for 24 hours in the presence of celecoxib or nimesulide showed an accumulation of these cells in the G₀/G₁ phase of cell cycle.Similar results were obtained in all repeated experiments.Conclusions1.COX-2 involves in the development of endometriosis.2.COX-2 inhibitors could sigficantly inhibit the proliferation of ectopic stromal cells cultured in vitro in a time and dose dependent mode(P＜0.05).3.COX-2 inhibtors could inhibit the proliferation of ectopic stromal cells via the mechanisms dependent on COX-2 and independent on COX-2.(1) COX-2 inhibitors down-regulated the level of PGE₂,exhibiting the inhibitory influence to ectopic endometrium..(2) COX-2 inhibitors inhibited endometriotic stromal cells via inducing the apoptosis rate of ectopic stromal cells and G0/G1 arrest.