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Assessment of the Cytotoxic and Immunomodulatory Effects of Substances in Human Precision-cut Lung Slices
Published on: May 9, 2018
Assessment of pulmonary toxicity in mice to evaluate human health risks from indoor airborne microorganisms
Mi-Kyung Song1, Jun Woo Kim1, Dong Im Kim1
1Center for Respiratory Research, Division of Jeonbuk Advanced Bio Research, Korea Institute of Toxicology, Jeongeup 56212, Republic of Korea.
Abstract:
Indoor air quality significantly impacts human health, with airborne microorganisms being a key pollutant. Although toxicity of indoor chemicals has been well-documented, the effects of inhalable microorganisms are not well understood. This study aims to assess the pulmonary effects of dominant resident airborne microorganisms collected from various locations across the Republic of Korea. Bacteria and fungi were isolated from indoor air samples collected from 240 to 1029 sites, and two strains each were selected for animal testing. C57BL/6 mice were exposed to these microorganisms via intratracheal instillation over four weeks. All exposure groups showed increased inflammatory cells and cytokines in broncho-alveolar lavage fluid, along with histological signs of lung injury, including inflammatory cell infiltration and mucous cell hyperplasia. The benchmark dose10 was then calculated for each adverse outcome as the mouse toxicity point of departure, which was converted to human equivalents to estimate the indoor microorganism exposure threshold capable of inducing toxic responses in humans. This threshold indicates that humans may be exposed to indoor fungi at potentially harmful levels which may lead to disease-associated inflammatory lung injury. Overall, this study provides toxicological evidence that can contribute to the development of improved standards for the management of indoor air microorganisms.
Insights
Indoor airborne microorganisms, like fungi, can cause lung inflammation and injury in humans. This study found potentially harmful exposure levels, highlighting the need for better indoor air quality standards.
Area of Science:
- Environmental Health
- Microbiology
- Toxicology
Background:
- Indoor air quality is crucial for human health, with airborne microorganisms posing a significant risk.
- While indoor chemical toxicity is known, the pulmonary effects of microorganisms are less understood.
- This research addresses the impact of resident airborne microbes on respiratory health.
Purpose of the Study:
- To assess the pulmonary effects of dominant airborne microorganisms found indoors in South Korea.
- To establish a human equivalent exposure threshold for adverse lung responses.
- To provide toxicological data for improved indoor air microorganism management standards.
Main Methods:
- Isolation of bacteria and fungi from 240-1029 indoor air sites across South Korea.
- Intratracheal instillation of selected microbial strains into C57BL/6 mice over four weeks.
- Analysis of broncho-alveolar lavage fluid for inflammatory markers and lung histology.
Main Results:
- All exposure groups exhibited increased inflammatory cells and cytokines in broncho-alveolar lavage fluid.
- Histological examination revealed lung injury, including inflammatory cell infiltration and mucous cell hyperplasia.
- Calculated benchmark dose (BMD10) and human equivalent exposure thresholds indicated potential harm from indoor fungi.
Conclusions:
- Indoor airborne microorganisms, particularly fungi, can induce toxic responses and lung injury in humans.
- Current indoor exposure levels may pose a risk for disease-associated inflammatory lung conditions.
- The findings support the development of stricter standards for managing indoor microbial contaminants.
