Perillyl alcohol (PA) mitigates inflammatory, oxidative, and histopathological consequences of allergic asthma in rats

Allergic asthma is an inflammatory and chronic condition, which is the most common asthma phenotype. It is usually defined by sensitivity to environmental allergens and leads to the narrowing of the airways. Around 300 million individuals are suffering from asthma worldwide. The purpose of the current research was to evaluate the effect of perillyl alcohol (PA) on oxidative stress and inflammation parameters in rats with allergic asthma. Experimental asthma was induced by ovalbumin (OVA) sensitization and inhalation in five groups of rats including control, asthma, asthma + vehicle, asthma + PA, and asthma + dexamethasone (Dexa). PA (50 mg/kg) or Dexa (2.5 mg/kg) were administered intraperitoneally for seven consecutive days following asthma induction. Histopathological evaluation was performed via hematoxylin and eosin (H & E) and Masson's trichrome staining. The enzyme-linked immunosorbent assay (ELISA) was used for the evaluation of the cytokine levels, including tumor necrosis factor alpha (TNF-alpha), interleukin (IL)-6, IL-17, and IL-10, as well as oxidative stress biomarkers including reactive oxygen species (ROS), superoxide dismutase (SOD), malondialdehyde (MDA), total antioxidant capacity (TAC), and glutathione peroxidase (GPx) in the lung tissue and bronchoalveolar lavage fluid (BALF). Real-time polymerase chain reaction (PCR) was utilized for assessing the mRNA expression of FOXP3 and GATA3 and western blot analysis was used for the measurement of nuclear factor kappa B (NF-kappa B) protein expression. PA and Dexa decreased the pathological alterations and the expression levels of inflammatory factors (cytokines, GATA3, and NF-kappa B) in the lung tissue and BALF of asthmatic rats. PA restored GPx, SOD, and TAC levels and reduced ROS, MDA, nitrite, and total protein in the lung and BALF. Overall, our findings demonstrated that PA can be used as a therapeutic agent in asthma patients, but it is essential to monitor its effects in future clinical studies.