Experimental substantiation of the efficacy of combined administration of loratadine and dry extract of hare's ear (Bupleurum aureum Fisch.) in an ovalbumin-induced allergic rhinitis model in immature rats

The present study comprehensively investigated the clinical manifestations, hematological, immunological, and biochemical parameters in immature rats with ovalbumin-induced allergic rhinitis following loratadine monotherapy and its combined administration with a standardized dry extract of Bupleurum aureum. The aim − to experimentally evaluate the effects of the combined administration of loratadine and a standardized Bupleurum aureum extract on the course of ovalbumin-induced allergic rhinitis in immature rats by assessing clinical manifestations, immune-inflammatory response, and oxidative stress parameters. Materials and methods. Experimental modeling of ovalbumin-induced allergic rhinitis in rats enables the reproduction of the main pathogenetic mechanisms of this disease and allows for a comprehensive assessment of both clinical manifestations and changes in the immune, hematological, and pro-/antioxidant systems. Such a model is informative for studying the efficacy of potential antiallergic agents and their effects on various components of the pathological process. Results. According to the results of experimental studies, ovalbumin-induced allergic rhinitis in immature rats weighing 70–100 g is accompanied by the development of a systemic IgE-mediated immune response, an inflammatory reaction, and oxidative stress, as evidenced by changes in clinical, hematological, biochemical, and immunological parameters, Loratadine monotherapy provides partial correction of allergic rhinitis manifestations, effectively reducing the severity of clinical symptoms and the level of pro-inflammatory mediators; however, it does not fully normalize systemic immunological and pro-/antioxidant disturbances, The use of a pharmaceutical syrup formulation containing loratadine and dry extract of Bupleurum aureum (DEBA) at a dose of 0.15 mg/kg in terms of loratadine and 0.15 mg/kg of DEBA demonstrates a more pronounced and balanced therapeutic effect, manifested by normalization of clinical signs, hematological parameters, markers of systemic inflammation, IgE-mediated immune response, and indicators of oxidative–antioxidative balance, The advantages of the combination therapy are likely due to the synergistic interaction of the components with different mechanisms of action, enabling effects on key pathogenetic links of allergic rhinitis—from the immediate histamine-mediated reaction to systemic inflammation and oxidative damage. Conclusion. Allergic rhinitis is one of the most common forms of IgE-mediated allergic diseases, characterized by both local manifestations in the nasal mucosa and systemic immunoinflammatory and metabolic disturbances. Its pathogenesis is primarily driven by activation of the Th2 immune response, increased IgE levels, histamine release and other inflammatory mediators, as well as eosinophil involvement and the development of oxidative stress, which contribute to the persistence and chronicity of the inflammatory process. Particular interest lies in the evaluation of the efficacy of loratadine monotherapy as a representative of H1-histamine receptor blockers, as well as its combined use with biologically active plant-derived components that may potentially influence the inflammatory and oxidative components of the allergic process. The combination of such approaches expands the understanding of possibilities for pathogenetic correction of allergic inflammation and helps to determine the advantages of multi-component therapy