ASSESSMENT OF INDOOR SECOND-HAND CIGARETTE SMOKE ON THE RESPIRATORY MECHANICS AND PREVENTIVE BENEFITS OF EUCALYPTOL: A MURINE MODEL

Second-hand smokers, in various settings such as recreational areas, schools, workplaces, homes and other enclosed public spaces also experience the detrimental effects of exposure to cigarette smoke (CS). Out of the 8 million deaths attributed to smoking, 1.2 million are a result of non-smokers being exposed to second-hand smoke. As a preventive strategy to these damages, Eucalyptol has been shown to be effective in the treatment of lung lesions caused by smoking. This study aimed to assess the effects of indoor second-hand cigarette smoke on respiratory mechanics and lung tissue, in addition to investigating the potential benefit of Eucalyptol against lung damage caused by this type of aggression. The experiments were conducted for 14 days with 40 BALB/c mice, divided into 5 groups: a control group, two groups nebulized with saline solution, divided into active and passive (second-hand) exposure to CS, two groups pre-treated with eucalyptol (10 mg/mL by nebulization) divided into active and passive exposure to CS. Lung mechanics data were collected on a flexiVent® small animal mechanical ventilator. In addition, ex vivo analysis of lung tissue micromechanics, morphometric analyzes and qualitative analyzes of lung tissue were performed. The results showed that 14 days of second-hand exposure generated significant tissue damage, causing infiltration of inflammatory cells and altering respiratory mechanics. However, pre-treatment with eucalyptol was able to prevent all changes caused by CS in both exposure protocols. We conclude that indoor second-hand smoke is capable of causing damage similar to active tobacco consumption and that Eucalyptol can be used as a preventive or nutritional resource against the changes caused by the inhalation of cigarette smoke.