Effect of mifepristone on COX-2 both in eutopic and ectopic endometrium in mouse endometriotic model

Abstract

To study the influence of mifepristone on the expression of cyclooxygenase 2 (COX-2) protein and COX-2 mRNA and then to evaluate the mechanism. After the establishment of 30 mice endometriosis models, the mice were randomly divided into six groups with 5 mice each group and assigned to experimental and control groups of 1-, 4- and 6-week circle according to whether mifepristone (0.13 mg d(-1)) was taken or not. Small animal optical imaging system was used to detect the fluorescent intensity of the ectopic tissue. Reverse transcript-polymerase chain reaction and western blot was used to examine COX-2 protein and COX-2 mRNA expression. ELISA was used to examine concentration of PGE(2) in serum. Mifepristone could not affect the fluorescent intensity of the ectopic endometrium after it was taken 1, 4, and 6 (P > 0.05). However, it could decrease the transcription of COX-2 mRNA in the 1 and 4 week groups (P < 0.05), while the difference in the 6 week group was not significant (P > 0.05). It could decrease the expression of COX-2 protein after it was taken 4 and 6 weeks (P < 0.05). The serous PGE(2) in the trial groups was lower than that in the control groups, but the difference was not significant (P > 0.05). This study showed that mifepristone could not affect the size of the ectopic endometrium, but it could decrease the transcription of COX-2 gene and then reduce the expression of COX-2 protein and its product PGE(2) which is an important factor which mediate pain. This maybe another mechanism that mifepristone takes effect through anti-inflammatory path.