Problem: Tumor necrosis factor-alpha (TNF-alpha) is secreted mainly during the menstrual phase and has been suggested to play a role in induction of apoptosis in endometrial cells and menstrual shedding. TNF-alpha receptor type 2 (TNF-RII) is believed to play a central role in TNFalpha-mediated cytotoxic, mitogenic, anti-proliferative and apoptotic effects. The aim of this study was to assess whether TNF-RII maybe expressed differentially in the endometrium of women with different degrees of endometriosis.
Method of study: TNF-RII expression in the endometrial tissue of women with and without endometriosis was investigated by immunohistochemical techniques and in situ hybridization.
Results: In histological sections, we observed TNF-RII mRNA and the corresponding protein localized mainly in endometrial glandular cells, with only very faint immunostaining in the surrounding stromal cells. Statistical analysis of our data showed a significant decrease in protein and mRNA expression of TNF-RII in endometrial glandular cells of patients with stages I and II endometriosis compared to normal subjects. TNF-RII expression was also found to decrease significantly in the secretory phase of the menstrual cycle in women with early endometriosis stages (I and II).
Conclusions: In view of the relevant role of TNF-RII in the modulation of the inflammatory and the proapoptotic effects of TNFalpha, deficient expression of TNF-RII mRNA in the endometrium of women at the earliest stages of endometriosis may play a significant role in the pathophysiology of this disease.