Oleanolic acid controls allergic and inflammatory responses in experimental allergic conjunctivitis

Area of Science:

• Ophthalmology
• Immunology
• Pharmacology

Background:

• Seasonal allergic conjunctivitis is commonly caused by pollen allergens.
• Allergen exposure triggers a Th2-immune response, leading to mast cell degranulation and eosinophil infiltration in the conjunctiva.
• Oleanolic acid (OA), a natural triterpene, possesses anti-inflammatory and immunomodulatory properties but its efficacy in ocular allergic conditions is unknown.

Purpose of the Study:

• To investigate the therapeutic potential of Oleanolic acid (OA) in a mouse model of Ragweed pollen (RWP)-induced allergic conjunctivitis (EAC).
• To evaluate the effects of OA on key inflammatory mediators and cellular responses in allergic conjunctivitis.

Main Methods:

• A Ragweed pollen (RWP)-specific allergic conjunctivitis (EAC) mouse model was utilized.
• Effects of OA on mast cell degranulation, eosinophil infiltration, IgE levels, Th2 cytokines, sPLA2-IIA, chemokines, and T-cell proliferation were assessed.
• In vitro studies examined OA's impact on eosinophils (EoL-1) and mast cells (RBL-2H3) exposed to inflammatory stimuli.

Main Results:

• OA treatment significantly reduced mast cell degranulation and eosinophil infiltration in conjunctival tissues of EAC mice.
• Allergen-specific IgE levels, Th2 cytokines, sPLA2-IIA, and chemokine levels were decreased in OA-treated EAC mice.
• OA suppressed RWP-specific T-cell proliferation and, in vitro, reduced inflammatory mediator synthesis in eosinophils and mast cells.

Conclusions:

• Oleanolic acid (OA) demonstrates significant anti-allergic and anti-inflammatory effects in an experimental model of allergic conjunctivitis.
• OA mitigates key cellular and molecular pathways involved in ocular allergic responses.
• These findings suggest OA as a promising therapeutic agent for allergic eye diseases.