Shimada Akinori, Miyake Kotaro, Kenmotsu Yuri, Ogihara Kikumi, Naya Yuko, Naota Misaki, Morita Takehito, Inoue Kenichiro, Takano Hirohisa
Department of Pathology, School of Life and Environmental Science, Azabu University, 252-5201 Sagamihara-shi, Japan.
Folia Histochem Cytobiol. 2018;56(1):38-48. doi: 10.5603/FHC.a2018.0006. Epub 2018 Mar 26.
I: NTRODUCTION: We have previously reported that Asian sand dust (ASD) induced acute and chronic inflammatory changes in the lung of mice. Zinc (Zn) is reported to influence inflammation and wound healing. The purpose of the study was to assess the effects of lowered serum Zn levels on the lung toxicity induced by ASD.
Mice that were fed diets containing normal (group 1) or low (group 2) content of Zn for 8 weeks were intratracheally instilled with 3.0 mg of ASD, followed by sacrifice at 24 hours, 2 weeks, and 1, 2 and 3 months after instillation. Paraffin sections of lung tissues were stained by hematoxylin and eosin and by immunohistochemistry to detect tumor necrosis factor (TNF) and interleukin (IL)-1β as well as inflammasome (NALP3), autophagy (LC-3) and lysosome (LAMP-1) markers. Selected samples of lung tissue were examined by electron microscopy.
Following histological examination of the lung, similar patterns of inflammatory changes were observed in mice with normal and low serum Zn concentrations; however, they were more prominent and persistent in mice with low serum Zn level. These changes were both purulent (acute) and pyogranulomatous (chronic) in nature. In the lung lesions of group 2 mice the changes within the cytoplasmic vacuoles of enlarged ASD-containing macrophages (Mo) were clearly visible. The macrophages expressed TNF and IL-1β, and semi-quantitative analysis revealed a larger number of TNF-positive Mo in mice with normal level of serum Zn and a larger number of IL-1β-positive Mo in mice with low level of serum Zn. Decreased positive LC-3 staining and dilated lysosomes containing ASD particles were observed in the cytoplasm of Mo in mice with low serum Zn concentration.
These findings suggest that low serum zinc concentration may induce the modulation of cytokine expression and lysosomal malfunction by phagocytotic and/or autophagic mechanisms, and may result in interstitial pyogranulomatous inflammation in the lungs of mice treated with ASD.
引言:我们之前报道过亚洲沙尘(ASD)可在小鼠肺部引发急性和慢性炎症变化。据报道,锌(Zn)会影响炎症和伤口愈合。本研究的目的是评估血清锌水平降低对ASD诱导的肺毒性的影响。
将喂食含正常(第1组)或低(第2组)锌含量饲料8周的小鼠经气管内注入3.0毫克ASD,然后在注入后24小时、2周以及1、2和3个月时处死。肺组织石蜡切片用苏木精和伊红染色,并通过免疫组织化学检测肿瘤坏死因子(TNF)、白细胞介素(IL)-1β以及炎性小体(NALP3)、自噬(LC-3)和溶酶体(LAMP-1)标志物。选取的肺组织样本通过电子显微镜检查。
对肺部进行组织学检查后,在血清锌浓度正常和低的小鼠中观察到了相似的炎症变化模式;然而,在血清锌水平低的小鼠中这些变化更显著且持续时间更长。这些变化兼具脓性(急性)和脓肉芽肿性(慢性)。在第2组小鼠的肺部病变中,含ASD的巨噬细胞(Mo)胞质空泡内的变化清晰可见。巨噬细胞表达TNF和IL-1β,半定量分析显示血清锌水平正常的小鼠中TNF阳性Mo数量较多,而血清锌水平低的小鼠中IL-1β阳性Mo数量较多。在血清锌浓度低的小鼠的Mo细胞质中观察到LC-3阳性染色减少以及含有ASD颗粒的溶酶体扩张。
这些发现表明,低血清锌浓度可能通过吞噬和/或自噬机制诱导细胞因子表达的调节和溶酶体功能障碍,并可能导致用ASD处理的小鼠肺部发生间质性脓肉芽肿性炎症。