Role of oxidative stress on diesel-enhanced influenza infection in mice

Abstract

Numerous studies have shown that air pollutants, including diesel exhaust (DE), reduce host defenses, resulting in decreased resistance to respiratory infections. This study sought to determine if DE exposure could affect the severity of an ongoing influenza infection in mice, and examine if this could be modulated with antioxidants. BALB/c mice were treated by oropharyngeal aspiration with 50 plaque forming units of influenza A/HongKong/8/68 and immediately exposed to air or 0.5 mg/m3 DE (4 hrs/day, 14 days). Mice were necropsied on days 1, 4, 8 and 14 post-infection and lungs were assessed for virus titers, lung inflammation, immune cytokine expression and pulmonary responsiveness (PR) to inhaled methacholine. Exposure to DE during the course of infection caused an increase in viral titers at days 4 and 8 post-infection, which was associated with increased neutrophils and protein in the BAL, and an early increase in PR. Increased virus load was not caused by decreased interferon levels, since IFN-β levels were enhanced in these mice. Expression and production of IL-4 was significantly increased on day 1 and 4 p.i. while expression of the Th1 cytokines, IFN-γ and IL-12p40 was decreased. Treatment with the antioxidant N-acetylcysteine did not affect diesel-enhanced virus titers but blocked the DE-induced changes in cytokine profiles and lung inflammation. We conclude that exposure to DE during an influenza infection polarizes the local immune responses to an IL-4 dominated profile in association with increased viral disease, and some aspects of this effect can be reversed with antioxidants.

Comparison of Lung Damages Due to Petrol and Diesel Car Smoke Exposures: Histological Study

“…The lung injuries were found as alveolar geometrical damage [30], loss of alveolar wall [31], hemorrhage [32], and the inflammation responses [33]. The destructive index [34] was used to analyze the damage level by following the eq.…”

N-acetylcysteine: an old drug with variable Anti-influenza properties

“…NAC was shown to have direct anti-viral effects, to decrease the levels of pro-inflammatory cytokines and to be anti-apoptotic (11,(13)(14)(15)(16)(17)(19)(20)(21)(22). Inhibition of mucin production and effects on B-and T-cell immune responses have also been reported (10,11,19).…”

“…A series of studies addressed the question of the effects of NAC on the outcome of influenza pneumonia (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22). NAC was shown to have direct anti-viral effects, to decrease the levels of pro-inflammatory cytokines and to be anti-apoptotic (11,(13)(14)(15)(16)(17)(19)(20)(21)(22).…”

“…The main effectors of the tissue damage associated with influenza infection are cytokines (the so-called cytokinic storm) and reactive oxygen species (ROS), mostly associated with neutrophils (28). NAC has emerged as a potent and safe anti-oxidant and immunomodulatory drug in the case of influenza pneumonia (11,(13)(14)(15)(16)(17)(18)(19)(20)22). …”

An observation of histological evidence on internal organ damages in mice caused by repeated exposures to motorcycle emissions

“…Besides, we also found edema with increases of bronchioalveolar lavage fluid. 26 Other effects include allergic reaction, nasal cavity inflammation and damage, pharyngeal problems, larynx damage, and influenza-like illness. 27,28 After passing the lung, the particles merge into the blood and cause erythrocyte damage.…”