Medium-dose estrogen ameliorates experimental autoimmune encephalomyelitis in ovariectomized mice

Area of Science:

• Neuroimmunology
• Endocrinology
• Autoimmune Diseases

Background:

• Estrogen exhibits neuroprotective properties relevant to central nervous system (CNS) disorders.
• The role of estrogen in autoimmune conditions like experimental autoimmune encephalomyelitis (EAE) requires further elucidation, particularly at pregnancy-relevant levels.

Purpose of the Study:

• To investigate the therapeutic potential of estrogen in mitigating EAE.
• To assess the impact of varying estrogen doses on immune cell profiles and CNS inflammation.

Main Methods:

• Ovariectomized mice were induced with EAE using MOG antigen.
• Mice received subcutaneous estrogen pellets for 21 days, with daily clinical monitoring.
• Histology, ELISA, flow cytometry, and real-time PCR were used to analyze CNS infiltration, T-cell differentiation, and transcription factor expression.

Main Results:

• Estrogen treatment significantly inhibited EAE development and reduced leukocyte infiltration into the CNS.
• Medium and high estrogen doses promoted T_H2 and T_reg cell responses (IL-4, IL-10, TGF-β) while suppressing T_H1 and T_H17 pathways (IFN-γ, IL-17, IL-6).
• Estrogen modulated transcription factor expression, increasing Foxp3 and GATA3 while decreasing T-bet and ROR-γt.

Conclusions:

• Estrogen demonstrates a suppressive effect on EAE, suggesting a potential therapeutic role in autoimmune CNS disorders.
• Pregnancy-level estrogen doses effectively reduced EAE incidence and severity by rebalancing T-cell populations and reducing inflammation.
• These findings highlight estrogen's immunomodulatory capacity and its potential application in treating autoimmune pathologies.