Cyclooxygenase-2 expression, Ki-67 labeling index, and perifocal neovascularization in endometriotic lesions

The effects of ulipristal on Bax/Bcl-2, cytochrome c, Ki-67 and cyclooxygenase-2 expression in a rat model with surgically induced endometriosis

OBJECTIVE

To evaluate the effect of ulipristal on Bax/Bcl-2, cytochrome C, Ki-67 and cyclooxygenase-2 expression in surgically induced endometriosis in a rat model.

STUDY DESIGN

We conducted a prospective, randomized, controlled, experimental study at the Experimental Research Center of the Iuliu Hatieganu University of Medicine and Pharmacy in Cluj-Napoca, Romania. Endometriosis was induced in 40 female Wistar albino rats by transplanting two autologous fragments of uterine horn onto bowel mesentery. After a 4-week induction period, we formed two groups: the first group was treated with ulipristal (UPA+) for 8 weeks, while the second group was treated only with the vehicle used for ulipristal (UPA-). We measured the volumes and masses of the implants both before and after treatment. A pathologist examined the sections microscopically for histological hallmarks of endometriosis. Immunostaining for Bax/Bcl-2, cytochrome C, Ki-67 and cyclooxygenase-2 (COX-2) was assessed in both groups.

RESULTS

Ulipristal reduced the average implant volume and mass, indicating that the drug is effective (P=0.01). The treatment induced a greater than 50% reduction in the volume and mass of endometrial implants, and the histological findings correspond to this result. The overall Bax positivity rate was higher in the group treated with ulipristal (42.37% vs. 21.05% for UPA+ and UPA-, respectively) (P=0.0062). The overall Bcl-2 positivity rate was smaller in the group treated with ulipristal (15% vs. 40% for UPA+ and UPA-, respectively) (P=0.0593). The cytochrome C global positivity rate was 5% in the UPA- group and increased to 50% in the UPA+ treatment group (P<0.0001). The COX-2 positivity rate decreased from 75% in the UPA- treatment group to 10% in the UPA+ treatment group (P<0.0001) and the Ki67 positivity rate also decreased from 55% in the UPA- group to 10% in the UPA+ treatment group (P<0.0002).

CONCLUSIONS

Treatment with ulipristal contributed to the regression and atrophy of endometriotic lesions in rats. The immunohistochemical expression profiles of Bax/Bcl-2 and cytochrome C revealed a pro-apoptotic effect of ulipristal. We also observed a reduced cellular proliferation, indicated by a decrease in Ki-67 expression and an anti-inflammatory effect, shown by a decrease in COX-2 expression after treatment with ulipristal.

Comparison of Ki-67 proliferative index between eutopic and ectopic endometrium: a case control study

OBJECTIVE

In this study, the Ki-67 proliferative indices among the stages of the endometriosis were compared to clarify whether the proliferation was increased with increasing disease stage.

MATERIALS AND METHODS

Thirty-eight patients who underwent surgery either by laparotomy or by laparoscopy with the diagnosis of endometriosis and 21 patients, as controls, who underwent hysterectomy with the diagnosis of myoma uteri and without any endometrial pathology at our hospital between 2005 and 2007 were studied. Biopsy specimens of endometriotic foci and endometriomas in study group, and eutopic endometrium of hysterectomy specimens of control group were studied.

RESULTS

Fifty-nine patients were divided into Group 1 (21 patients in control), Group 2 (19 patients in stage I and II of endometriosis), and Group 3 (19 patients in stage III and IV). A moderate correlation between the stage of endometriosis and the degree of Ki-67 staining was found. When Ki-67 immunohistochemical staining was considered according to the threshold value for CA-125 (35 U/mL), Ki-67 positivity was increased with the increase in CA-125 value, but this increase was not statistically significant.

CONCLUSION

Endometriosis shows some characteristics of tumors such as high rate of invasion, getting autonomy, and proliferation as the disease progresses with subsequent damage to target organs. When the stage of the disease increases, environment becomes more suitable for increased proliferation and invasion. In this study, the increase in proliferative activity as the severity increases is shown by the increase in Ki-67 index. As more studies are being conducted in this field, pathogenesis will be clarified, which could help in the development of new treatment modalities.