PM2.5混悬液染尘大鼠肺银染色的组织病理学观察

目的观察PM2.5混悬液染尘大鼠的肺组织病理学改变及银染色显示肺内尘粒的效果。方法将收集的游离PM2.5制成混悬液，72只Wistar大鼠随机分为低剂量组（每0．2ml含PM2.50．3nag）、中剂量组（每0．2ml含PM2.50．75mg）、高剂量组（每0．2ml含PM2.52mg）和对照组，每组18只。3个实验组分别以不同的剂量采用支气管肺内滴入方式染尘，每周染尘1次。分别于染尘后第4、12及24周时，取肺脏，石蜡包埋组织切片进行HE染色及沃森一斯塔理（Worthin-Starry，WS）银染色观察、透射电镜（TEM）观察，对肺内尘粒进行X-线质谱元素分析（X-RSA）。计数大鼠肺内肉芽肿样病变的数目，测定肺内尘粒的沉积程度、平均积分吸光度值（IOD）和平均积分面密度值（IAD）。结果随着染毒时间的延长和染毒剂量的增大，大鼠肺内肉芽肿样病变的数目及其细胞质内尘粒的IAD值和IOD值也逐渐增高。这些尘粒在WS染色切片上呈黑褐色，更清晰；其IOD值和IAD值均明显高于HE染色下的测定值，差异有统计学意义（P〈0．05）；尘粒IOD值与肉芽肿病变数目呈正相关关系（r=0．639，P〈0．01）。TEM下大鼠肺内尘粒的超微结构与游离的PM2.5相同，X-RSA分析两者的主要元素成分也相同，均为硅元素。结论PM2.5混悬液染尘可以引起大鼠肺内出现肉芽肿样病变，WS银染色方法可以较好地显示被吞噬细胞吞噬后的PM2.5，其染色效果优于HE染色。

Histopathology of lung of rats exposed to suspension of PM2.5 with silver staining

OBJECTIVE: To observe the histopathological changes of the lung of rats which exposed to the suspension of PM(2.5) and detect the effect of silver staining showing dust particles deposited in the lungs. METHODS: The dissociative PM(2.5) of Beijing city was collected to make suspension. The rats were divided into different groups and exposed to different dosage of PM(2.5) (0.3 mg/0.2 ml per rat, 0.75 mg/0.2 ml per rat, 2 mg/0.2 ml per rat) by intratracheal instillation every week. These rats were sacrificed at 4, 12 weeks and 24 weeks (total dosage: 7.2 mg per rat, 18 mg per rat, 48 mg per rat) after the treatment, and their lungs were sampled. The pathological varieties and the situation of these rats' lungs were observed macroscopically and using hematoxylin and eosin (HE) staining, Warthin-Starry (WS) silver stain, as well as the transmission electron microscope (TEM). The dust particles in these rats' lungs were observed by x-ray spectrum chemical element analysis (X-RSA). The granulomatous lesion in the lungs of the rats was counted, and the deposition degree, intergrated optical density (IOD) value and integrated area density (IAD) value of the dust particles deposited in the lungs were measured. The variance, least significance difference, and the unitary linear related and regression were analyzed. RESULTS: The number of the granulomatous lesion in the lungs of the rats became more and more with time. In WS staining the dust particles were dark brown and became clearer. The IOD and IAD value of these dust particles were much higher in WS staining than that in HE staining (P < 0.05). The IOD value of the dust particles was positively correlated with the number of the granulomatous lesion (R = 0.639, P < 0.01). The ultrastructure of the dust particles in the rats' lungs and the dissociative PM(2.5) was basically same in TEM. Their main compositions were similar, by X-RSA, and both of them were silicon. CONCLUSION: The suspension of PM(2.5) could result in the granulomatous lesion in the lung of rats. WS silver staining is a good method to show PM(2.5) phagocytized by macrophage, and is better than HE staining.