Mucopolysaccharidosis (MPS IIIA) mice have increased lung compliance and airway resistance, decreased diaphragm strength, and no change in alveolar structure.

Mucopolysaccharidosis type IIIA (MPS IIIA) is characterized by neurological and skeletal pathologies caused by reduced activity of the lysosomal hydrolase, sulfamidase, and the subsequent primary accumulation of undegraded heparan sulfate (HS). Respiratory pathology is considered secondary in MPS IIIA and the mechanisms are not well understood. Changes in the amount, metabolism, and function of pulmonary surfactant, the substance that regulates alveolar interfacial surface tension and modulates lung compliance and elastance, have been reported in MPS IIIA mice. Here we investigated changes in lung function in 20-wk-old control and MPS IIIA mice with a closed and open thoracic cage, diaphragm contractile properties, and potential parenchymal remodeling. MPS IIIA mice had increased compliance and airway resistance and reduced tissue damping and elastance compared with control mice. The chest wall impacted lung function as observed by an increase in airway resistance and a decrease in peripheral energy dissipation in the open compared with the closed thoracic cage state in MPS IIIA mice. Diaphragm contractile forces showed a decrease in peak twitch force, maximum specific force, and the force-frequency relationship but no change in muscle fiber cross-sectional area in MPS IIIA mice compared with control mice. Design-based stereology did not reveal any parenchymal remodeling or destruction of alveolar septa in the MPS IIIA mouse lung. In conclusion, the increased storage of HS which leads to biochemical and biophysical changes in pulmonary surfactant also affects lung and diaphragm function, but has no impact on lung or diaphragm structure at this stage of the disease.NEW & NOTEWORTHY Heparan sulfate storage in the lungs of mucopolysaccharidosis type IIIA (MPS IIIA) mice leads to changes in lung function consistent with those of an obstructive lung disease and includes an increase in lung compliance and airway resistance and a decrease in tissue elastance. In addition, diaphragm muscle contractile strength is reduced, potentially further contributing to lung function impairment. However, no changes in parenchymal lung structure were observed in mice at 20 wk of age.

Treatment with inhaled aerosolised ethanol reduces viral load and potentiates macrophage responses in an established influenza mouse model.

AIM: Treatment options for viral lung infections are currently limited. We aimed to explore the safety and efficacy of inhaled ethanol in an influenza-infection mouse model. MATERIALS AND METHODS: In a safety and tolerability experiment, 80 healthy female BALB/c mice (20 per group) were exposed to nebulized saline (control) or three concentrations of ethanol (40/60/80% ethanol v/v in water) for 3x30-minute periods, with a two-hour break between exposures. In a separate subsequent experiment, 40 Female BALB/c mice were nasally inoculated with 104.5 plaque-forming units of immediate virulence "Mem71" influenza. Infection was established for 48-h before commencing treatment in 4 groups of 10 mice with either nebulized saline (control) or one of 3 different concentrations of ethanol (40/60/80% ethanol v/v in water) for 3x30-minute periods daily over three consecutive days. In both experiments, mouse behavior, clinical scores, weight change, bronchoalveolar lavage cell viability, cellular composition, and cytokine levels, were assessed 24-h following the final exposure, with viral load also assessed after the second experiment. RESULTS: In uninfected BALB/c mice, 3x30-minute exposures to nebulized 40%, 60%, and 80% ethanol resulted in no significant differences in mouse weights, cell counts/viability, cytokines, or morphometry measures. In Mem71-influenza infected mice, we observed a dose-dependent reduction in viral load in the 80%-treated group and potentiation of macrophage numbers in the 60%- and 80%-treated groups, with no safety concerns. CONCLUSIONS: Our data provides support for inhaled ethanol as a candidate treatment for respiratory infections.

The respiratory health effects of acute in vivo diesel and biodiesel exhaust in a mouse model.

BACKGROUND: Biodiesel, a renewable diesel fuel that can be created from almost any natural fat or oil, is promoted as a greener and healthier alternative to commercial mineral diesel without the supporting experimental data to back these claims. The aim of this research was to assess the health effects of acute exposure to two types of biodiesel exhaust, or mineral diesel exhaust or air as a control in mice. Male BALB/c mice were exposed for 2-hrs to diluted exhaust obtained from a diesel engine running on mineral diesel, Tallow biodiesel or Canola biodiesel. A room air exposure group was used as a control. Twenty-four hours after exposure, a variety of respiratory related end point measurements were assessed, including lung function, responsiveness to methacholine and airway and systemic immune responses. RESULTS: Tallow biodiesel exhaust exposure resulted in the greatest number of significant effects compared to Air controls, including increased airway hyperresponsiveness (178.1 ± 31.3% increase from saline for Tallow biodiesel exhaust exposed mice compared to 155.8 ± 19.1 for Air control), increased airway inflammation (63463 ± 13497 cells/mL in the bronchoalveolar lavage of Tallow biodiesel exhaust exposed mice compared to 40561 ± 11800 for Air exposed controls) and indications of immune dysregulation. In contrast, exposure to Canola biodiesel exhaust resulted in fewer significant effects compared to Air controls with a slight increase in airway resistance at functional residual capacity and indications of immune dysregulation. Exposure to mineral diesel exhaust resulted in significant effects between that of the two biodiesels with increased airway hyperresponsiveness and indications of immune dysregulation. CONCLUSION: These data show that a single, brief exposure to biodiesel exhaust can result in negative health impacts in a mouse model, and that the biological effects of exposure change depending on the feedstock used to make the biodiesel.