Poster abstracts
Poster number 101 submitted by Zachary Weisenseel
Sex-specific interactions among physiological responses, cytokine expression, and microglial morphology following endotoxic challenge in the California Mouse
Zachary H. Weisenseel (Neuroscience Graduate Program, The Ohio State University), Anastasia Cocieru (College of Arts and Sciences, The Ohio State University), Huazhen Chen (Department of Neuroscience, The Ohio State University College of Medicine), Erica R. Glasper
Abstract:
Background: Stress-related inflammatory and neurological conditions disproportionately affect women. Microglia mediate sex-specific neuroinflammatory responses triggered by lipopolysaccharide (LPS), a bacterial endotoxin that systemically activates Toll-like receptor-4. The California mouse (Peromyscus californicus) is a monogamous rodent species with distinct corticosterone (CORT) regulation and sex differences in stress and immune responses. Addressing LPS- and CORT-dependent effects on microglial activity and cytokine expression may reveal sex-specific interactions between endocrine and immune function.
Methods: Male and female California mice (5-6-months old) received an intraperitoneal injection of LPS (1 mg/kg) or saline. At 4 or 24-hours post-injection, body weight change was recorded, and blood and tissue were collected. Circulating CORT and splenic cytokines were quantified, and microglial morphology in the dentate gyrus was analyzed. Statistical models evaluated relationships among CORT, weight loss, cytokines, and microglial structure.
Results: LPS induced weight loss and elevated CORT, cytokines, and microglial activation, which largely resolved by 24 hours. At 4 hours, females exhibited higher interleukin (IL)-1β expression while males displayed greater IL-10. CORT and weight loss displayed sex‑dependent associations with cytokine levels and microglial morphology. LPS‑treated females showed stronger cytokine responses and more ameboid microglia, while vehicle‑treated males showed CORT‑linked maintenance of homeostatic morphology.
Conclusion: Enhanced IL‑1β expression and microglial activation in females may contribute to prolonged neuroinflammation relevant to mood and autoimmune disorders, whereas CORT may exert neuroprotective effects in males. These findings demonstrate pronounced sex differences in neuroimmune responses in California mice and highlight the importance of including sex as a biological variable when studying stress–immune interactions.
Keywords: lipopolysaccharide, corticosterone, immune challenge