title: A simple method for the formalin fixation of lungs in toxicological pathology studies.
abstract: Optimized lung preparation for detailed structural evaluation is required to improve consistency in preclinical safety evaluation, differences of opinion exist among regulatory agency personnel regarding the optimal methods for routine formalin fixation of lungs from rodent toxicology studies. The simple tracheal ligation fixation method emphasizes tracheal ligation before opening the thorax instead of attempting to re-inflate after lung collapse when opening the thorax. Photomicrographs of this method demonstrated an unprecedented ability to maintain the natural lung architecture, in contrast to the unavoidable changes in the alveolar environment by the intratracheal instillation and vascular perfusion methods. In addition, a comparison of fixation methods on lung morphology in a rodent model of LPS-induced acute lung injury demonstrated that the tracheal ligation fixation method may provide a standard approach for morphometry. Additionally, a TUNEL assay was used to determine the degree of autolysis, which revealed that the autolysis was insignificant in the central areas of each lobe of the lung compared to the lung periphery by tracheal ligation fixation. In conclusion, our novel modified method, which avoids the disadvantages of generating artifacts, fulfills the requirement of preserving the clear, natural morphology of the lung making it suitable and worthy of recommendation for toxicological studies in a good laboratory practice (GLP) lab.
authors.affiliation: State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Beijing 100850, China.
authors.forename: Wen-Sheng
authors.initials: WS
authors.lastname: Qu
authors.affiliation: State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Beijing 100850, China.
authors.forename: Ji-Ye
authors.initials: JY
authors.lastname: Yin
authors.affiliation: State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Beijing 100850, China. Electronic address: whemei@ailyun.com.
authors.forename: He-Mei
authors.initials: HM
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Beijing 100850, China.
authors.forename: Yan-Sheng
authors.initials: YS
authors.lastname: Dong
authors.affiliation: State Key Laboratory of Toxicology and Medical Countermeasures, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences, Beijing 100850, China. Electronic address: dingrigao@bmi.ac.cn.
authors.forename: Ri-Gao
authors.initials: RG
authors.lastname: Ding
mesh_terms: D000818:Animals; D017209:Apoptosis; D016477:Artifacts; D005557:Formaldehyde; D020287:In Situ Nick-End Labeling; D008026:Ligation; D008168:Lung; D008297:Male; D010336:Pathology / Q000379:methods*; D051381:Rats; D017207:Rats, Sprague-Dawley; D016707:Tissue Fixation / Q000379:methods*; D014116:Toxicology / Q000379:methods*; D014132:Trachea
chemical_list: D005557:Formaldehyde
keywords: Intratracheal instillation; Lung fixation; Toxicologic pathology