A comparative investigation of the effects of vitamin D3 and buserelin acetate on experimentally induced endometriosis

Endometriosis is a condition that develops as a result of extrauterine presence of endometrial tissue causing chronic inflammation. Buseralin acetate is a GnRH analogue used in the treatment of endometriosis in clinical practice. In this study we compared the effects of buserelin acetate and vitamin D, which is known to suppress angiogenesis and stimulate apoptosis. For this purpose, endometriosis was induced surgically in 10 weeks old, 28 female Sprague Dawley rats. 28 days after the first surgery, abdomen of the rats were opened and size of the endometriotic implants in the peritoneum were measured and adhesion scores were calculated. Then the rats were randomly assigned into 4 groups. Rats in the first group were administered intramuscular NaCl solution for 28 days. Vitamin D3 dissolved in dimethyl sulfoxide was administered intramuscularly to the rats in second group for 28 days, whereas the animals in the third group were given only intramuscular solution of dimethyl sulfoxide for 28 days. And in the fourth group, the animals were subcutaneously administered buserelin acetate dissolved in distilled water once a week for 3 weeks. At the end of the experiments, the endometriotic implants of the sacrificed rats were excised with surrounding abdominal wall, after their size and adhesion scores were evaluated. For histomorphological evaluations, tissue sections were stained with hematoxylin eosin and Masson trichrome techniques. Proapoptotic and antiapoptotic processes in the tissue sections were evaluated immunohistochemically using Bcl-2 and Bax antibodies and TUNEL method. In addition, levels of TNF-α as inflammation marker and levels of VEGF to evaluate the angiogenesis process, were measured in peritoneal fluid samples of rats. When evaluated together findings and results in vitamin D treated group were similar to those in the buserelin acetate treated group. Therefore, vitamin D may have a role in improvement of endometrial implants by means of regression in fibrotic areas and stimulation of the apoptotic process.