Development of a large-scale computer-controlled ozone inhalation exposure system for rodents

Area of Science:

• Toxicology
• Environmental Health
• Laboratory Animal Science

Background:

• Laboratory-based inhalation toxicology studies often require custom-made exposure systems due to commercial unavailability.
• Developing reliable and precise exposure systems is crucial for accurate toxicological assessments.

Purpose of the Study:

• To design, construct, and validate a novel in vivo rodent ozone inhalation exposure system.
• To create a large-capacity system with automated control for precise ozone concentration management.

Main Methods:

• Utilized two Hazelton H-1000 exposure chambers (capacity: 180 mice or 96 rats each).
• Implemented an empirically tuned proportional-integral-derivative control loop for stable ozone concentrations (0.2-2 ppm).
• Integrated automated data collection for airflow and environmental conditions, alongside safety systems.

Main Results:

• Demonstrated consistent ozone exposures within and across experiments, indicated by low coefficients of variation.
• Observed consistent biological responses (airway inflammation) in mice, validating exposure consistency.
• System achieved stable ozone concentrations within ~8 minutes, maintained for typical 3-hour exposures.

Conclusions:

• A large-scale, robust rodent ozone inhalation exposure system has been successfully developed.
• The system facilitates future research on the health effects of ozone exposure in rodents.
• Automated control and data acquisition enhance the reliability and efficiency of inhalation toxicology studies.