A NOVELLA OF MICE AND MEN: IMMUNOLOGICAL AND REPRODUCTIVE ALTERATIONS IN A PRISTANE-INDUCED MOUSE MODEL OF SYSTEMIC LUPUS ERYTHEMATOSUS AFTER HORMONAL THERAPY

PV013 / #145 Poster Topic: AS02 - Animal Models Background/Purpose Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by an aberrated immune response against nuclear, cytoplasmic and cell surface antigens. Symptoms often aggravate in females during their active reproductive years, indicating a significant interaction between the reproductive and immune systems. Given the urgency of understanding how SLE can influence female fertility and the role of hormones in disease manifestation, this study aims to investigate these questions. Notably, we utilize mouse models of SLE, a unique and valuable tool for studying the interactions of different systems and the impact of lupus development on oogenesis. Methods We successfully induced lupus-like symptoms in healthy Balb/C mice through intraperitoneal injection of the hydrocarbon oil pristane. The mice were randomly assigned to 4 groups (10 animals per group). One group of pristane-injected and another group of intact, healthy Balb/C mice were subjected to hormonal stimulation. Following standardized procedures of in vitro stimulation in humans, an exemplary short protocol was adapted to a prospective mouse model. One group of pristane-injected and another group of intact, healthy Balb/C mice were subjected to hormonal stimulation. The initial stimulation included 9 days of using products with a follicle-stimulating function. From day 7th to the final 11th day, the mice were subjected to stimulation with a Gonadotropin-releasing hormone antagonist, combined on the final day with human chorionic gonadotropin with luteinizing function. The dose conversion of the corresponding doses of all hormones was calculated using Equivalent Dose (HED) calculation based on the Km ratio. Control groups of pristane-injected mice and healthy animals were treated with PBS only. To follow-up on the immune status of these experimental animals, we utilized flow cytometry, ELISpot, and ELISA. The diversity of autoantibodies, histological changes, and oocyte quality were meticulously examined using fluorescent microscopy. Results A single intraperitoneal injection of pristane sparked the production of autoantibodies and led to the deposition of IgG-containing immune complexes in the kidneys, resulting in proteinuria. Notably, hormonal stimulation in the lupus-model mice significantly increased the percentage of proinflammatory immune cell subtypes, changed ANA immunofluorescence imaging patterns, and elevated the number of plasmacytes producing anti-dsDNA IgG antibodies. The ANA immunofluorescent staining was described according to the corresponding ANA patterns in humans, according to the International Consensus on ANA Patterns (ICAP). Additionally, depositions of IgG-containing immune complexes were detected in both the kidneys and ovaries of treated mice, alongside observable structural abnormalities in isolated oocytes. Conclusions The observed oocyte impairments in pristane-treated mice are compelling evidence of a disrupted local microenvironment due to disease activity. They underscore the critical interplay between autoimmunity and reproductive health, and their significance could influence future research and clinical practice in this field. This study was supported by National Science Fund, Bulgaria, grant number [КP-06-H53/8/2021] and the European Fund for regional development through Operational Program Science and Education for Smart Growth 2014 - 2020, Grant BG05M2OP001-1.002-0001-C04 “Fundamental Translational and Clinical Investigations on Infections and Immunity”.