123: Rodent-Specific Behavioral Signatures and Peritoneal Immune Shifts in a Mouse Endometriosis Model

Topic: Basic Science
Subtopic: Pain category (ICD-11), Chronic primary visceral / pelvic pain, , , , , Neuroimmunology, Assessment and Measurement of Pain/Nociception, Behavioral studies, , , ,

Background and Aims: Endometriosis-related chronic pain spans sensory, affective, and functional domains, yet most rodent studies used to translate to pain in patients reduce this complexity to evoked hypersensitivity, overlooking ongoing, disability-relevant behaviors and biological correlates. We aim to characterize non-evoked pain behavior, stratify clinically-relevant endometriosis pain phenotypes across mouse models, and link these to longitudinal molecular signatures in blood and lesions to align preclinical signals with patient data and prioritize mechanisms and biomarkers. Here, we present data from one endometriosis mouse model using complementary readouts—continuous home-cage behavior, evoked mechanical sensitivity, and peritoneal immune-cell profiling—to identify stratification signals for multi-omics analyses.

Methods: Female mice underwent intraperitoneal induction of deep-infiltrating endometriosis-like lesions using full-thickness uterine tissue fragments (MI model (1)); sham-operated animals served as controls. Spontaneous behavior was continuously recorded in group-housed cages (four per cage) using an automated monitoring system, extracting spatial, diurnal, and resting metrics up to day 42. Social features included inter-animal proximity and distance to peers. Evoked mechanical sensitivity was assessed longitudinally by weekly hind-paw von Frey testing. Peritoneal immune-cell composition was quantified at day 42 by flow-cytometric analysis of lavage samples, focusing on myeloid and macrophage subsets defined by CD11b, F4/80, MHC-II, CD163, and CD36 expression.

Results: Continuous home-cage monitoring detected altered spontaneous behavior, with lesion-bearing mice exhibiting increased total distance traveled and greater time spent socially isolated. In contrast, weekly hind-paw von Frey testing up to day 42 after intraperitoneal induction did not reveal a statistically robust mechanical hypersensitivity in lesion-bearing mice compared with controls (preliminary: control n=4; lesion n=5). Flow-cytometric analysis of peritoneal lavage at day 42 showed modest immune changes, including a slight overall increase in peritoneal macrophages with decreased large and increased small subsets. T cells and neutrophils trended upward, whereas monocyte and B-cell populations remained largely stable.

Conclusions: Our findings indicate that the MI model of endometriosis expresses rodent-specific behavioral signatures, including increased locomotor distance and greater social isolation in the home cage. These changes reflect alterations in spontaneous, ethologically relevant behavior that capture ongoing burden beyond reflexive responses and provide a richer phenotype for stratification. Immune profiling indicates a subtle inflammatory shift, with modest macrophage expansion and redistribution toward small peritoneal subsets, alongside trend-level increases in T cells and neutrophils. Integrating behavioral phenotyping with immune and molecular analyses may improve stratification and support identification of mechanisms and translational biomarker candidates.

References: 1. Dodds KN, Beckett EAH, Evans SF, Hutchinson MR. Lesion development is modulated by the natural estrous cycle and mouse strain in a minimally invasive model of endometriosis. Biol Reprod 2017;97:810–821.

Presenting Author: Bruno Pradier
Submitting Author: Bruno Pradier

Senior Author: Esther Pogatzki-Zahn

IASP 2026 Global Year theme of Neuropathic Pain: No

• Bruno Pradier: PhD - University Hospital Münster, Münster, Germany
• Daniel Segelcke: PhD - University Hospital Münster, Münster, Germany
• Noelia Alonso-Gonzalez: PhD - University of Münster, Münster, Germany
• Irene Aranda-Pardos: PhD - University of Münster, Münster, Germany
• Mirjam Augustin - University Hospital Münster, Münster, Germany
• Esther Pogatzki-Zahn: MD, PhD - University Hospital Münster, Münster, Germany