Zinc Protects against Swine Barn Dust-Induced Cilia Slowing

Area of Science:

• Environmental Health
• Occupational Medicine
• Respiratory Physiology

Background:

• Agricultural workers in swine concentrated animal feeding operations (CAFOs) face risks of chronic lung disease due to organic dust exposure.
• Organic dust extracts (ODEs) impair mucociliary clearance by slowing cilia beat frequency (CBF), increasing inflammation and reducing bacterial clearance.
• Nutritional zinc deficiency is linked to chronic lung disease, prompting an investigation into zinc's protective role.

Purpose of the Study:

• To investigate the effect of zinc supplementation on organic dust-induced cilia slowing in agricultural workers.
• To determine if zinc can mitigate the negative impacts of swine barn organic dust on respiratory tract defense mechanisms.

Main Methods:

• Ciliated mouse tracheal epithelial cells were pretreated with varying concentrations of ZinPro (a zinc supplement) before exposure to 5% ODE.
• Cilia beat frequency (CBF) and protein kinase C epsilon (PKCε) activity were measured to assess the impact of ODE and zinc.
• Cell viability and toxicity were evaluated at different ZinPro concentrations.

Main Results:

• ODE exposure significantly slowed CBF, which was reversed by ZinPro pretreatment at 0.5 and 1.0 µg/mL.
• ZinPro effectively inhibited ODE-stimulated PKCε activation in a dose-dependent manner.
• ZinPro showed no toxicity to ciliated cells at effective concentrations, unlike high concentrations of zinc salts.

Conclusions:

• Zinc supplementation, particularly with ZinPro, can reverse organic dust-mediated cilia slowing.
• The protective effect of zinc appears to involve the inhibition of the PKCε pathway.
• Zinc supplementation holds potential as a therapeutic strategy to protect CAFO workers from chronic lung disease by enhancing mucociliary function.