Activity of catalase in surgically induced endometrial-like lesions in rats

Hypothesis/aims of study. There is a link between the activities (and polymorphisms of genes) of antioxidant enzymes and endometriosis. It is also known that progesterone induces some antioxidant enzymes in the endometrium and that progesterone analogs are effective for reduction of endometrial lesions. In addition to morphometric and histological estimations of endometriosis regression, it could be useful to assess the activity of antioxidant enzymes within endometriotic foci. The present study is aimed at estimating the activity of catalase, a hydrogen peroxide-detoxifying enzyme, in surgically induced endometrial-like lesions with a variable degree of reduction. Study design, materials and methods. The study was carried out on 12 mature female rats of Wistar strain. Endometrial-like lesions were induced by autotransplantation of uterine tissue fragments on the abdominal wall. After 35-37 days, the endometrial foci were extracted. Catalase activity in the ectopic endometrium was determined by the Beers Sizer method modified as follows: recording hydrogen peroxide concentration decrease at 250 nm and using 3-amino-1,2,4-triazole (AT) to assess specificity. The correlation between the specific catalase activity and protein amount in the ectopic endometrium was estimated. Results. At the wavelength of 250 nm, a relatively weak interference of AT with other components of the reaction mixture was observed, which allows using the specific catalase inhibitor to indicate the enzyme activity. The activity is measured in a short period of incubation (less than 1 minute) and is proportional to amount of the endometrial tissue extract in the reaction mixture. As a rule, the most reduced endometriotic foci (with the lowest weight) possessed a higher catalase activity (the Spearmans rho was 0.66 with p 0.025). Conclusion. The method for determining catalase activity was adapted to work with endometriotic foci. With p 0.025, we can accept that a low weight of endometriotic foci is linked with a relatively high catalase activity within their tissue. The results allow suggesting the involvement of catalase in reduction of endometrial lesions.