Potential anti‐inflammatory effects of nebulized local anesthetics on inhaled chlorine lung injury (834.8)

Abstract

Chlorine (Cl2) is a chemical used in both industry and society alike, despite it being a highly irritant and reactive gas. Acute exposure can result in symptoms of airway obstruction such as wheezing, shortness of breath, mouth/nose/chest pain, and bronchospasm. Currently, there is no known antidote for chlorine’s poisoning effects. Potential treatments include topical exposure of the airways to nebulized drugs such as local anesthetics which have been shown to improve the mobility of monitored animals after exposure to Cl2 gas. In this research project, we assess the effects of the nebulized local anesthetics lidocaine (1% and 4%), 3% 2‐Chloroprocaine following exposure to 100 or 400 ppm of chlorine gas on biochemical measurements of injury to airway. Wet‐to‐dry lung weight ratios, bronchoalveolar lavage (BAL) cell counts and total protein, and lung homogenate cytokine levels were determined 24 hours after Cl2 gas exposure and anesthetic treatment. In mice exposed to 400 ppm Cl2 gas, 1% lidocaine had the greatest decrease of wet‐to‐dry lung weight ratio in addition to lower live cell infiltration and lower protein concentrations in BAL fluids indicating a potential anti‐inflammatory affect. Cytokine levels from lung homogenates after exposure and treatments had a decreasing trend compared to untreated animals. Levels of IL‐10, IFNγ, MCP‐1 and IL‐13 were significantly lower in the 1% lidocaine animal group. Similar but not identical results were found following treatment with 100ppm Cl2. Treatment with 4% lidocaine and 3% 2‐chloroprocaine had potential toxic effects. This study indicates that nebulized 1% lidocaine is potentially a good treatment option after chlorine induced lung injury based on behavioral and biochemical data.Grant Funding Source: Supported by 1R21ES022876