Effect of long-acting β2-agonist and corticosteroid combination treatment on parotid glands of rats (histological and immunohistochemical study)

Bronchial asthma is a common chronic condition frequently managed with corticosteroids, β2 receptor agonists, or their combination. While these therapies effectively control respiratory symptoms, emerging evidence suggests they may adversely affect oral and salivary gland health. However, most existing studies focus on inhalation-related tooth erosion or xerostomia, with limited histological evidence on glandular changes. This study uniquely investigates the direct impact of combination therapy of salmeterol and fluticasone propionate on the parotid glands using histological and immunohistochemical analyses. to evaluate the possible effect of long-acting β2-agonist (Salmeterol) and corticosteroid (Fluticasone propionate) combination treatment on parotid glands and assess the histological and immunohistochemical changes. 36 male albino rats were allocated into control and experimental groups. The experimental group received daily intraperitoneal injections of a combination of salmeterol and fluticasone propionate powder at a dosage of 0.55 mg/kg/day, while the control group was administered an equal volume of saline. Nine rats from each group were sacrificed at 14 and 25 days of treatment. The parotid glands were dissected at each time point and subjected to histological examination using H&E and immunohistochemical staining for α-SMA. Histological examination of group II after 14 days, serous acini appeared spherical with hyperchromatic nuclei, while ducts showed epithelial thinning and stagnant secretion. By 25 days, acini became irregular with cytoplasmic vacuolations, increased spacing, and inflammatory infiltration. Engorged blood vessels were observed. Immunohistochemical results using anti-α-SMA staining proved a significant decrease in myoepithelial activity compared to the control group. Prolonged combination treatment leads to quantitative and qualitative changes in parotid salivary glands, potentially impacting oral and dental health. Therefore, greater attention should be given to the oral health of individuals using this medication.