Damage to Olfactory Organs of Adult Zebrafish Induced by Diesel Particulate Matter

Particulate matter (PM) is an environmental hazard that is associated with various human health risks. The olfactory system is directly exposed to PM; therefore, the influence of PM exposure on olfactory function must be investigated. In this study, we propose a zebrafish olfactory model to evaluate the effects of exposure to diesel particulate matter (DPM), which was labeled Korean diesel particulate matter (KDP20). KDP20 comprises heavy metals and polycyclic aromatic hydrocarbons (PAHs). KDP20 exposed olfactory organs exhibited reduced cilia and damaged epithelium. Olfactory dysfunction was confirmed using an odor-mediated behavior test. Furthermore, the olfactory damage was analyzed using Alcian blue and anti-calretinin staining. KDP20 exposed olfactory organs exhibited histological damages, such as increased goblet cells, decreased cell density, and calretinin level. Quantitative real-time polymerase chain reaction (qRT-PCR) revealed that PAHs exposure related genes (AHR2 and CYP1A) were upregulated. Reactive oxidation stress (ROS) (CAT) and inflammation (IL-1B) related genes were upregulated. Furthermore, olfactory sensory neuron (OSN) related genes (OMP and S100) were downregulated. In conclusion, KDP20 exposure induced dysfunction of the olfactory system. Additionally, the zebrafish olfactory system exhibited a regenerative capacity with recovery conditions. Thus, this model may be used in future investigating PM-related diseases.

Confocal microscopy 3D imaging of diesel particulate matter

To date, diesel particulate matter (DPM) has been described as aggregates of spherule particles with a smooth appearing surface. We have used a new colour confocal microscope imaging method to study the 3D shape of diesel particulate matter (DPM); we observed that the particles can have sharp jagged appearing edges and consistent with these findings, 2D light microscopy demonstrated that DPM adheres to human lung epithelial cells. Importantly, the slide preparation and confocal microscopy method applied avoids possible alteration to the particles’ surfaces and enables colour 3D visualisation of the particles. From twenty-one PM10 particles, the mean (standard deviation) major axis length was 5.6 (2.25) μm with corresponding values for the minor axis length of 3.8 (1.25) μm. These new findings may help explain why air pollution particulate matter (PM) has the ability to infiltrate human airway cells, potentially leading to respiratory tract, cardiovascular and neurological disease.

Underground Gold Miner Exposure to Noise, Diesel Particulate Matter and Crystalline Silica Dust

Background. Respirable dust, diesel particulate matter, crystalline silica and noise pollution are the most common causes of health issues experienced by underground mine workers. Assessment of exposure levels in relation to standard regulatory body permissible levels is essential for the safety of mine workers. Objectives. The present study compared exposure levels of diesel particulate matter, crystalline silica dust and noise experienced across different underground mine worker job titles. Methods. Subjective sampling was employed using gravimetric air samplers over an 8-hour time weighted average for two periods designated as period 1 (first half of the year) and period 2 (second half of the year). A comparative analysis of exposure levels between job titles and in relation to the National Institute for Occupational Safety and Health (NIOSH) permissible exposure levels (PELs) was performed. Results. In the present study, 90% of the selected job titles were over-exposed to noise and 80% were over-exposed to diesel particulate matter. The highest exposures for crystalline silica dust and diesel particulate matter were found in the 40–49-year-old age group. Conclusions. The present study of exposure levels of diesel particulate matter, respirable dust, crystalline silica, and noise during underground gold mining demonstrates that better control mechanisms are needed to protect workers. Participant Consent. Obtained Ethics Approval. This study was approved by the Ethics Committee of the Kwame Nkrumah University of Science and Technology, Ghana. Competing Interests. The authors declare no competing financial interests.