Aluminum hydroxide nebulization-induced redox imbalance and acute lung inflammation in mice.

Purpose: Aluminum is the third most abundant metal in the earth's crust and is widely used in industry. Chronic contact with aluminum results in a reduction in the activity of electron transport chain complexes, leading to excessive production of reactive oxygen species (ROS) and oxidative stress. This study aimed to evaluate the effects of short-term exposure of aluminum hydroxide on oxidative stress and pulmonary inflammatory response.Materials and methods: Male BALB/c mice were divided into three groups: control group (CG); phosphate buffered saline group (PBSG) and aluminum hydroxide group (AHG). CG was exposed to ambient air, while PBSG and AHG were exposed to PBS or aluminum hydroxide solutions via nebulization, three times per day for five consecutive days. Twenty-four hours after the last exposure, all animals were euthanized for subsequent analysis.Results: Exposure to aluminum hydroxide in the blood resulted in lower platelet levels, higher neutrophils, and lower monocytes compared to CG and PBSG. Aluminum hydroxide promoted the recruitment of inflammatory cells to the lung. Macrophage, neutrophil and lymphocyte counts were higher in AHG compared to CG and PBSG. Protein oxidation and superoxide dismutase activity were higher, while catalase activity and reduced and oxidizes glutathione ratio in AHG were lower compared to CG and PBSG. Furthermore, there was an increase in the inflammatory markers CCL2 and IFN-γ in AHG compared to CG and PBSG.Conclusion: In conclusion, short-term nebulization with aluminum hydroxide induces the influx of inflammatory cells and oxidative stress in adult BALB/c mice.

Intranasal instillation of distilled water, hypertonic saline and sodium bicarbonate promotes redox imbalance and acute lung inflammation in adult mice.

Bronchial obstruction, caused by retained secretions, is often treated by the administration of mucoactive agents including distilled water, saline, hypertonic saline, and sodium bicarbonate. However, the inflammatory effect of these solutions on the lungs remains unclear. This study evaluated the instillation effects of different solutions on oxidative stress and lung inflammatory response in C57BL/6 mice. Fifty C57BL/6 mice were divided into 5 groups: control (CG); distilled water (DWG), hypertonic saline (HSG), saline (SG) and sodium bicarbonate (SBG). CG was exposed to ambient air while DWG, HSG, SG and SBG had 50 µl of respective solutions administered intranasally for 5 consecutive days. Twenty-four hours after the last intranasal instillation, all animals were euthanized for subsequent analysis. All solutions promoted increased recruitment of inflammatory cells to the lung compared to controls. Superoxide dismutase activity was lower in HSG compared to all other groups; catalase activity was reduced in SG, while it increased in SBG and DWG compared to CG. Finally, there was an increase in the inflammatory markers TNF-α, CCL2 and IFN-γ in DWG compared to CG, SG and HSG. In conclusions, the intranasal instillation of different solutions promotes redox imbalance and inflammation on lungs of adult mice.