Protective properties of AgNPs green-synthesized by Camellia sinensis on ovalbumin-induced allergic conjunctivitis

Allergic conjunctivitis is the main usual red eye cause influencing many people. Allergic conjunctivitis is like an umbrella that includes different types of clinical manifestations, from a mild but annoying form of IgE-dependent allergy to inhaled allergens to very severe forms such as keratoconjunctivitis. Cornea involvement in allergic conjunctivitis needs the steroids use, which can cause severe eye complications. Research on allergic conjunctivitis should focus more on more severe forms of eye allergies to gain a better the pathophysiology understanding of the disease, diagnosis methods should be standardized and new treatment methods should be suggested. In the recent study, due to high therapeutic effects of Camellia sinensis, we used its aqueous extract for green-synthesizing of the silver nanoparticles and allergic conjunctivitis treatment in the in vivo condition. UV–Vis spectroscopy, FE-SEM and TEM were used for characterization of nanoparticles. This research therefore evaluated the AgNPs@Camellia sinensis antiallergic potential in ovalbumin-induced allergic conjunctivitis and attempted to predict its mode of action. ELISA determined serum ovalbumin-specific total IgE, IgE and IgG. Clinical scores for allergic conjunctivitis induced by intraperitoneal ovalbumin sensitization and topical conjunctival challenge in Dunkin-Hartley guinea pigs were estimated after treatment with 10, 20, 40 and 80 µg kg⁻¹ AgNPs@Camellia sinensis, 10 mg kg⁻¹ chlorpheniramine, 30 mg kg⁻¹ prednisolone, or 10 mL kg⁻¹ PBS. Serum ovalbumin-specific total IgE, IgE and IgG decreased significantly (p < 0.01). The conjunctival tissue in AgNPs@Camellia sinensis treated guinea pigs had mild mononuclear infiltration compared to the PBS-treated ones, which had intense conjunctival tissue inflammatory infiltration. The 40 and 80 mg kg⁻¹ AgNPs@Camellia sinensis treatment resulted in allergic conjunctivitis low clinical score.