Biological effects of inhaled hydraulic fracturing sand dust in rats

The pulmonary inflammatory response to inhalation exposure to fracking sand dust (FSD) was investigated in a rat model. Adult male Sprague-Dawley rats were exposed by whole-body inhalation to air or an aerosol of FSD at concentrations of 10 or 30 mg/m3, 6 hours/day for 4 days. The control and FSD-exposed rats were euthanized at post-exposure time intervals of 1, 7 or 27days and pulmonary inflammatory, cytotoxic and oxidant responses were determined. Deposition of FSD particles was detected in the lungs of all the FSD-exposed rats. Analysis of bronchoalveolar lavage parameters of toxicity, oxidant generation, and inflammation did not reveal any significant persistent pulmonary toxicity in the FSD- exposed rats. Similarly, the lung histology of the FSD-exposed rats showed only minimal changes in influx of macrophages following the exposure. Determination of global gene expression profiles detected significant differential expressions of only six and five genes in the 10 mg/m3, 1 day post-exposure, and the 30 mg/m3, 7-day post-exposure FSD groups, respectively. Taken together, data obtained from the present study demonstrated that FSD inhalation exposure resulted in minimal/no toxicity or gene expression changes in the lungs of the rats.本研究构建大鼠模型，探究了吸入暴露于压裂砂尘（Fracking Sand Dust, FSD）所诱发的肺部炎症反应。选取成年雄性斯普拉格-道利大鼠，采用全身吸入染毒方式，使其暴露于空气，或浓度分别为10 mg/m³、30 mg/m³的压裂砂尘气溶胶环境，每日染毒6小时，连续染毒4天。分别于染毒后1天、7天、27天对对照组及压裂砂尘染毒组大鼠实施安乐死，并检测其肺部炎症、细胞毒性与氧化应激相关反应。所有压裂砂尘染毒组大鼠的肺部均检出压裂砂尘颗粒沉积。对支气管肺泡灌洗液的毒性、氧化产物生成及炎症相关参数进行分析后发现，压裂砂尘染毒组大鼠未出现显著的持续性肺部毒性反应。与之类似，压裂砂尘染毒组大鼠的肺部组织病理学检查结果仅显示，染毒后巨噬细胞浸润仅存在极轻微变化。全基因组表达谱检测结果显示，在染毒后1天的10 mg/m³浓度组，以及染毒后7天的30 mg/m³浓度组中，仅分别存在6个和5个差异表达基因。综上，本研究所得数据表明，吸入暴露于压裂砂尘仅会导致大鼠肺部出现极轻微或无明显的毒性反应及基因表达变化。