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

Abstract

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.

Keywords:

• Aluminum hydroxide
• inflammation
• lung
• mice
• oxidative stress

Acknowledgments

FSB would like to express their gratitude to CAPES for your Post-Doctoral fellowship (CAPES-PVEX-Process # 88881.172437/2018-01) in the Interdepartmental Division of Critical Care Medicine, St. Michael’s Hospital, University of Toronto, Toronto, ON, Canada. FSB and AT are in credit with the CNPq for the fellowship of research productivity.

Conflict of interest

The authors declare that they have no competing interests in this study.