Biological responses in rats exposed to cigarette smoke and Middle East sand (dust)

Abstract

Respiratory symptoms are frequently reported in personnel deployed to the Middle East. This project characterized the respiratory toxicity of inhaled Iraqi sand (IS). Adult rats underwent a 6-wk inhalation to air or mainstream cigarette smoke (MSCS) (3 h/d, 5 d/wk) that included exposure to IS or crystalline silica (1 mg/m(3), 19 h/d, 7 d/wk) or air during the last 2 weeks. Assessments included motor activity, whole-body plethysmography, cytological and biochemical analysis of bronchoalveolar lavage fluid, lung metal burden, nasal and lung pathology, and changes in lung protein and gene expression. A number of metals including nickel, manganese, vanadium, and chromium were detected in IS. Elevated lung parenchyma aluminum, silica, barium, manganese, and vanadium concentrations were seen in IS-exposed rats, suggesting that several metals present in IS are bioavailable. Rats exposed to IS only developed mild inflammation in the anterior nose and lung. Silica inhalation was associated with some pulmonary responses that were not seen in IS-exposed rats, such as mild laryngeal and tracheal inflammation, mild tracheal epithelial hyperplasia, and elevated lung silica concentrations. MSCS inhalation with or without co-exposure to either IS or silica resulted in changes consistent with pulmonary inflammation and stress response. Rats exposed to MSCS and silica had more widespread airway lesions when compared with rats exposed to MSCS only. Silica-exposed rats had more robust pulmonary gene expression and proteomic responses than that seen in IS-exposed rat. Our studies show that the respiratory toxicity of IS is qualitatively similar to or less than that seen following short-term silica exposure.

A Systematic Review of Global Desert Dust and Associated Human Health Effects

“…These results suggest that the exacerbation of pneumonia by desert dust was due to the enhanced production of pro-inflammatory mediators via activation of TLR2 and NALP3 inflammasome pathways in alveolar macrophages [149]. Many study results suggest that the allergic inflammation aggravated by mineral dust may be due to mineral elements (mainly SiO 2 ), and thus the biological effects of desert dust approximate those of silica [138,150,151]. Dust sampled from different sites over the world is dominated by silicon dioxide (SiO 2 ) and aluminum oxide (Al 2 O 3 ).…”

Evaluation of the Pulmonary Toxicity of Ambient Particulate Matter From Camp Victory, Iraq

“…The distribution of elements in the Ir dust resembles that of the Ku dusts (Table 1), and while measurements of the content of the Camp Victory soil used by Dorman et al, (2012) were not presented, the composition of Camp Victory soil and ambient dust is similar (Engelbrecht et al 2009a; 2009b). The dusts also appear to have a large clay mineral component based on mineralogical analysis (Engelbrecht et al 2009a; 2009b) and elemental composition (National Institute of Science and Technology 2012).…”

“…In the first, rats were exposed to settled dust collected at Camp Buehring in northern Kuwait (Wilfong et al 2011) by intratracheal (IT) instillation, and in the second, rats received a whole-body exposure for 2 wk using aerosolized milled surface soil collected at Camp Victory, Baghdad, Iraq (Dorman et al 2012). Neither study found marked pathological effects as a result of exposure.…”

Developing the Second Generation of Improvised Explosive Device Detector Dog

“…In part 1, dogs were trained to discriminate between AN and a nylon mesh blank. In part 2 the dogs discriminated between AN and a 5 g soil sample collected from Camp Victory Iraq (see Dorman et al, (2012) for additional details about the soil sample). In part 3, the dogs were trained to discriminate between AN and amyl acetate, a chemical with a marked banana odor.…”