Immunohistochemical Localization of Endothelial Nitric Oxide Synthase in Endometrial Tissues of Women With Uterine Myomas

Objectives: Nitric oxide (NO) is a free radical that plays important roles in variety of physiological aspects of the female reproductive system. Pathophysiological findings revealed a potential role of the endothelial isoform of nitric oxide synthase (eNOS) enzyme in female reproductive disorders specifically in the endometrium. This study investigates the expression of eNOS in the endometrial tissue to study the potential role of this enzyme and its NO production in infertility of women with uterine myomas. Materials and Methods: A total of 20 endometrial tissues were obtained, 10 infertile women with uterine fibroids and 10from normal and fertile women, 7 to 9 days after LH surge. Following fixation with paraformaldhyde, frozen sections of samples were prepared for semi-quantitative immunohistochemical evaluation using monoclonal anti-human eNOS antibody. Hematoxylin and eosin staining was used for histological dating of the samples Results: Localization of eNOS was seen in glandular and luminal epithelium, vascular endothelium and stroma in both fertile women and infertile women with uterine fibroids. Despite the differences in immunoreactivity of luminal epithelium, vascular endothelium and stroma in both groups, higher levels of eNOS in glandular epithelium was statistically significant in women with uterine fibroids compared to the control group. Conclusions: The findings suggest that over-expression of eNOS in glandular epithelium may affect the preparation stage of endometrium for fertility in women with uterine myomas.