HMGB-1 Increases Proinflammatory Reaction via TLR4 in Human Granulosa Cells of Endometriosis

Background/Objectives: Oxidative stress is a critical factor in the development and progression of endometriosis. Granulosa cells, which reside near oocytes in follicles, exhibit steroidogenic activity, and, consequently, influence oocyte quality. Increased oxidative stress may induce the danger signal such as HMGB-1 in granulosa cells and eventually change the follicular environment of patients with endometriosis. This study aimed to demonstrate that HMGB-1 and its receptors, TLR4 and RAGE, play important roles in the changes in the follicular environment in infertile patients with endometriosis. Methods: In the immortalized human granulosa cell line (hGL5), cell proliferation and apoptosis assay, ELISA for estradiol, qRT-PCR for HMGB-1 and TLR4, Western blot for apoptosis-related and NF-κB pathway-related proteins, and ELISA for inflammatory molecules IL-1β and IL-6 were performed after H₂O₂ treatment. Results: H₂O₂ treatment to the hGL5 cell line decreased cell proliferation via apoptosis and, as a result, decreased steroidogenesis. Also, it increased the gene expression of HMGB-1 and TLR4, increased the protein expression related to the NF-κB pathway, and increased the release of inflammatory molecules IL-1β and IL-6. Conclusions: The results indicate that oxidative stress associated with endometriosis may increase inflammation by interacting with HMGB-1 and TLR4 and activating the NF-κB pathway to increase proinflammatory responses. The findings of this study may provide insight into endometriosis with decreased oocyte quality.