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Updated: May 14, 2026
Mouse Model of Surgically-induced Endometriosis by Auto-transplantation of Uterine Tissue
Published on: January 6, 2012
[Effect of letrozole on endometrosis and apoptosis of ectopic endometrial cells in rats]
Xiaomeng Xia1, Lilu Guo, Jinping Su
1Department of Gynecology and Obstetrics, Second Xiangya Hospital, Central South University, Changsha 410011, China.
Objective:
To investigate the therapeutic mechanism of letrozole, the third-generation aromatase inhibitor, on endometriotic lesions in a rat model and its effect on the apoptosis of ectopic endometrial cells.
Methods:
Endometriosis was induced by autotransplanting pieces of uterus onto the peritoneum in rats. The rats with successful ectopic implants were divided into 2 groups: A letrozole group (n=15) and a control group (n=15). The volume, appearance, and histopathology of ectopic implant were determined before and after the treatment. Expression of P450arom, COX-2, bcl-2, and bax in the ectopic implant was detected by immunohistochemistry and RT-PCR in the 2 groups.
Results:
The volume of ectopic implant in the letrozole group was significantly reduced compared with the control group (P<0.05). The protein and mRNA levels of P450arom and COX-2 in the ectopic implant were significantly decreased in the letrozole group compared with the control group (P<0.05). There was a positive correlation between the expression of P450arom and the expression of COX-2 (r=0.943, P<0.001; r=0.913, P<0.001). The protein and mRNA expression of bcl-2 was significantly decreased (P<0.05), and the bax protein and mRNA expression was significantly increased (P<0.05) in the ectopic implant with an increased bax/bcl-2 ratio in the letrozole group compared with the control group (P<0.05).
Conclusion:
Letrozole can obviously reduce the size of ectopic implant through decreasing P450arom and COX-2 expression, suppressing the secretion of estrogen, inhibiting the proliferation, and inducing the apoptosis of ectopic implants.
