Kedi Alerjenlerinin Hava Yolu Yeniden Yapılanmasına ve Oksidatif Stres Üzerine Etkisi

Abstract

In respiratory diseases, whose global prevalence is steadily increasing, exposure to allergens significantly affects the onset and severity of the disease. Airway epithelial cells, which constitute the primary barrier against inhaled allergens, protect the airways from external agents through their chemical and immune functions, as well as their physical barrier role. Airway allergens can be broadly classified as indoor and outdoor allergens. Among indoor allergens, cat allergens are among the most frequently encountered. Although there are studies in the literature demonstrating the disruptive effects of cat allergens on the epithelial barrier structure, research highlighting their impacts on oxidative stress and airway remodeling, both of which hold a pivotal role in the pathology of respiratory diseases, remains limited and insufficient. This thesis aims to investigate the effects of Fel d 1 and Cat Dander Extract (CDE) allergens on processes associated with airway remodeling and oxidative stress. In this context, a co-culture system comprising bronchial epithelial cells (16HBE14o-) and fibroblast cells (CCD-16Lu) was established to mimic the airway microenvironment. To evaluate airway remodeling, the protein expressions of α-SMA, Vimentin, and Collagen I in CCD-16Lu cells were analyzed via Western Blotting, while their gene expression levels were examined using Real-Time Polymerase Chain Reaction (qPCR). The levels of Matrix Metalloproteinases (MMP-2, MMP-9) and their tissue inhibitors (TIMP-1, TIMP-2) were measured by Enzyme-Linked Immunosorbent Assay (ELISA), and their corresponding gene expressions were determined in CCD-16Lu cells. Oxidative stress parameters were evaluated using 16HBE14o- cells. The gene expressions of HMOX1, NOX4, TXNRD1, and GPX4, which are associated with oxidative stress and antioxidant activity, were analyzed by Real-Time PCR, and total intracellular ROS levels were determined through ROS assays. Following the experiments and data analyses, a dose-dependent increase in the gene and protein expressions of α-SMA and Collagen I, key markers associated with airway remodeling, was detected upon stimulation with both allergens. ELISA results revealed an alteration in the MMP/TIMP balance, indicating that allergen-stimulated cells failed to tolerate the accumulation of proteins such as collagen. The dose- and allergen-dependent increases observed in TIMP-1 and TIMP-2 levels suggest a cellular response activated to counteract the tissue damage induced by the allergens. Overall, the findings of this thesis demonstrate that airway remodeling and oxidative stress, which play crucial roles in respiratory diseases such as asthma, are significantly affected by cat allergens, and the underlying mechanisms vary depending on the specific allergen stimulation.