纳米级炭黑颗粒的小鼠亚急性吸入毒性研究

Subacute Toxicity Study of Nanoscale Carbon Black Particles by Dynamic Inhalation Exposure in Mice

[目的]探讨纳米级炭黑颗粒的小鼠亚急性吸入毒性效应,为纳米级炭黑危险性评价提供毒理学数据。[方法]8周龄雄性C57BL/6小鼠分为低质量浓度(后称"浓度")组(15 mg/m^3)、高浓度组(30 mg/m^3)和阴性对照组(滤过空气)。通过气溶胶发生器将纳米级炭黑吹入染毒柜中,每天染毒6 h,连续染毒28 d。染毒期间,动态监测染毒柜内炭黑颗粒的空气动力学直径、颗粒的空间分布及浓度变化。末次染毒后24 h,取静脉血进行血液学及临床生化检查;采集心、肺、肝、脾、肾等脏器组织,称重后计算脏器系数,并行组织病理学检查;支气管灌洗肺组织后,镜下对灌洗液中细胞进行分类计数并测定总蛋白浓度。[结果]染毒28 d期间,低浓度组炭黑浓度约为(15.31±3.30)mg/m^3,高浓度组为(30.05±14.20)mg/m^3。与对照组相比,各组小鼠染毒期间饲料和水的消耗量及其体重变化差异均无统计学意义。与对照组相比,各浓度组染毒小鼠血生化指标未见明显变化,而血常规指标中仅红细胞计数、血红蛋白浓度和红细胞比容在染毒组中略有增加(P<0.01或P<0.05)。高浓度组小鼠肺脏器系数高于低浓度组和对照组(P=0.016),各浓度组心、肾脏器系数降低(P=0.001,P<0.01)。病理检查可见各浓度组小鼠肺组织呈灰黑色,支气管腔、肺泡腔内均可见炭黑颗粒物沉积,肺间质可见吞噬炭黑颗粒的巨噬细胞,且高浓度组炭黑颗粒沉积更多;浓度组小鼠肺组织损伤病理评分分别为(6.63±1.13)和(9.80±0.38),明显高于对照组(1.66±0.55)。与对照组相比,低、高浓度组肺泡灌洗液中总细胞数、淋巴细胞数、中性粒细胞数和嗜酸性粒细胞数均明显增加(均P<0.01)。[结论]28 d反复吸入纳米级炭黑主要引发小鼠肺组织损伤,本结果也可为开展纳米级炭黑肺毒性研究提供较为理想的模型和可靠的分析手段。

[Objective] To investigate the subacute toxicity by dynamic inhalation exposure of nanoscale carbon black particles in mice, and to provide toxicological data for the risk assessment of nanoscale carbon black particles. [Methods] Eightweek-old male C57BL/6 mice were randomly assigned into three groups, including negative control group（filtered air）, low dose group（15 mg/m^3 carbon black particles）, and high dose group（30 mg/m^3 carbon black particles）. With aerosol generator, nanoscale carbon black particles of designed concentrations were blown into chambers, the mice were exposed through inhalation for 6 h per day for 28 d continuously. During the exposure period, the aerodynamic diameter, spatial distribution, and concentrations of carbon black particles were monitored dynamically. In 24 h after the last exposure, venous blood samples were collected for haematologic and clinical biochemical examinations. The heart, lung, liver, spleen, and kidney were dissected and weighed for pathological examination. Differential cell count of bronchoalveolar lavage fluid（BALF） were conducted under microscope and the total protein level in BALF was detected. [Results] The concentrations of carbon black particles in the low and high dose groups were（15.31±3.30） mg/m^3and（30.05±14.20） mg/m^3 respectively during the 28-day exposure period. No significant differences of body weight and the consumption of feed and water were observed between the control and exposed groups. The blood biochemical indicators showed no changes between the control and exposed groups. Compared with the control group, red blood cells, hemoglobin concentration, and hematocrit increased slightly in the exposed groups（P〈0.01 or P〈0.05）. In comparison with the control and the low dose groups, there was an increasement of the lung organ coefficient in the high dose group（P=0.016）; whereas the heart and kidney organ coefficient in the two exposed groups decreased（P=0.001, P〈0.01）. The histopathologic examination results showed that carbon black particles were deposited in the pulmonary alveoli or bronchioles in the exposed groups, especially in the high dose group, and were swallowed by macrophages in pulmonary interstitial. The pathological score of lung injury in the low and high dose groups were（6.63±1.13） and（9.80±0.38） respectively, both higher than that in the control group（1.66±0.55）. Compared with the control group, the total cell counts, lymphocytes, neutrophils, and eosinophils in BALF were higher in the two exposed groups（all Ps〈0.01）. [Conclusion] The 28-day repeated inhalation exposure to carbon black particles could mainly result in lung tissue injury, providing an ideal model and a reliable analytical method for the study of pulmonary toxicological effects induced by nanoscale carbon black particles.