Background: Obesogens are environmental chemicals that disrupt neuroendocrine systems to produce obesity. A prior study of obese patients presenting to an Emergency Department found a statistically significant correlation between body mass index and use of air fresheners. Association does not prove causation butmotivates further investigations. This study screened for health effects of mice chronically exposed to an over-the-counter air freshener.
Methods: Research design was a randomized controlled trial at an AAALAC-accredited animal care facility. Ten C57 BL/6 female adolescent mice weighing about 28 grams were randomized to an exposure group (N=6) and a control group (N=4). Mice were housed in a cage with an automobile air freshener containing a complex mixture of volatile organic chemicals for 39 days. Weight was recorded weekly. Measurements obtained pre- and post-exposure were weight and lean and fat body mass by EchoMRI® . Neuropsychological measurements were prepulse inhibition, open field activity, novel object test, Y-maze, elevated zero maze, Barnes maze, and tail suspension test. At the end of the study period, mice were anesthetized with tribromomethanol for terminal data collection. Tracheostomy was performed. Pulmonary function tests were performed with a Flexivent®. Statistical analysis was performed using paired t-tests and ANOVA As appropriate.
Results: Mice in the two groups increased their weights at the same rate, and both showed a significant increase in the fat/lean ratio, with no differences between the groups with respect to these outcomes. No differences were found between the two groups in any of the neuropsychological tests. There was no difference in Newtonian (central airways) resistance at baseline between the two groups. However, in the exposed group there was a trend toward increased Newtonian resistance with provocation with 12 mg/mL of acetylcholine (0.617+0.094 v 0.50+0.042).
Conclusion: This preliminary pilot study found no difference between exposed and control mice in weight, lean and fat mass, and neuropsychological parameters. There was a trend for increased Newtonian resistance in exposed mice which is the parameter most closely related to the asthma-like trait of increased sensitivity to a bronchoconstrictor. Further research is needed to delineate this possible adverse health effect of air fresheners.