Oral exposure to cadmium and mercury alone and in combination causes damage to the lung tissue of Sprague-Dawley rats
Oral exposure to cadmium and mercury alone and in combination causes damage to the lung tissue of Sprague-Dawley rats
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DOI：
10.1016/j.etap.2019.03.021
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发表时间：
2019-07-01
影响因子：
4.3
通讯作者：
Oberholzer, Hester Magdalena
中科院分区：
文献类型：
--
作者：
Naidoo, Sirasha Venketsamy Koopsamy;Bester, Megan Jean;Oberholzer, Hester Magdalena
环境的存在和人类暴露于空气和香烟烟雾中的重金属导致了全球呼吸道疾病的增加。重金属经口暴露对肝脏和肾脏结构和功能的影响已被广泛研究，而呼吸系统作为一个靶点往往被忽视。该研究的目的是调查可能的结构变化，在肺组织的Sprague-Dawley大鼠经口暴露28天后，镉（Cd）和汞（Hg），单独和组合在1000倍的世界卫生组织的限制，每种金属在饮用水中。暴露后，使用组织学技术和透射电子显微镜评价细支气管和肺的一般形态以及胶原蛋白和弹性蛋白分布。在肺中，肺泡的结构变化包括肺泡腔塌陷、存在炎性细胞和肺泡壁增厚。此外，暴露于镉和汞引起的肺泡结构的退化，导致融合的肺泡。细支气管形态学变化包括平滑肌质量增加，管腔上皮变性、分离和聚集。显着的细支气管相关的淋巴组织中存在的组暴露于镉和汞。超微结构检查证实存在纤维化，其中在镉暴露组，胶原纤维排列致密，而在汞暴露组，额外的突出弹性蛋白。这项研究确定了肺部作为重金属毒性的目标，在口服暴露后导致细胞损伤、炎症和纤维化，并增加呼吸系统疾病的风险，其中汞显示出最大的纤维化效应，与镉结合进一步加剧。
Environmental presence and human exposure to heavy metals in air and cigarette smoke has led to a worldwide increase in respiratory disease. The effects of oral exposure to heavy metals in liver and kidney structure and function have been widely investigated and the respiratory system as a target is often overlooked. The aim of the study was to investigate the possible structural changes in the lung tissue of Sprague-Dawley rats after oral exposure for 28 days to cadmium (Cd) and mercury (Hg), alone and in combination at 1000 times the World Health Organization's limit for each metal in drinking water. Following exposure, the general morphology of the bronchiole and lungs as well as collagen and elastin distribution was evaluated using histological techniques and transmission electron microscopy. In the lungs, structural changes to the alveoli included collapsed alveolar spaces, presence of inflammatory cells and thickening of the alveolar walls. In addition, exposure to Cd and Hg caused degeneration of the alveolar structures resulting in confluent alveoli. Changes in bronchiole morphology included an increase in smooth muscle mass with luminal epithelium degeneration, detachment and aggregation. Prominent bronchiole-associated lymphoid tissue was present in the group exposed to Cd and Hg. Ultrastructural examination confirmed the presence of fibrosis where in the Cd exposed group, collagen fibrils arrangement was dense, while in the Hg exposed group, additional prominent elastin was present. This study identified the lungs as target of heavy metals toxicity following oral exposure resulting in cellular damage, inflammation and fibrosis and increased risk of respiratory disease where Hg showed the greatest fibrotic effect, which was further, aggravated in combination with Cd.