Pathologic changes in 3-methylindole-induced equine bronchiolitis.
Abstract: The pathologic features of bronchiolitis were studied in horses and ponies from 30 minutes to 27 days after an oral dose of 3-methylindole (3MI). From 30 minutes to 3 hours, lesions were limited to nonciliated bronchiolar epithelial (Clara) cells, which lost apical caps and cytoplasmic granules and had dilated smooth endoplasmic reticulum (SER). At 12 hours, necrotic Clara cells were exfoliated; degeneration and necrosis were evident, in bronchiolar ciliated cells. Rare epithelial cells with hyperplastic SER appeared on the denuded basal lamina at 24 hours. Inflammatory cells, epithelia, fibroblastlike cells, collagen, and debris occluded many bronchiolar lumens from 3 to 6 days. Reorganization resulted in a simple columnar bronchiolar epithelium with relatively normal ciliated cells and fewer fibroblastlike cells. However, mature Clara cells were rare at 27 days, and collagenous bands still divided bronchiolar lumens. Thus, 3MI toxicosis is a persistent model of equine bronchiolitis with many morphologic features of the spontaneous disease.
Publication Date: 1983-02-01 PubMed ID: 6824066PubMed Central: PMC1916146
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
- Research Support
- Non-U.S. Gov't
- Research Support
- U.S. Gov't
- P.H.S.
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
This research studied the pathological changes in horse and pony bronchioles after ingesting a substance known as 3-methylindole (3MI). The results indicated that 3MI toxicity induced bronchiolitis and resulted in pronounced structural changes, some of which persisted even after 27 days.
Initial Incidence of Bronchiolitis
- The study commenced with observing equine bronchioles from half an hour to 27 days after horses and ponies ingested 3-Methylindole (3MI). Initial changes appeared thirty minutes to three hours post-ingestion.
- During this phase, lesions were restricted to non-ciliated bronchiolar epithelial (Clara) cells. These cells lost their apical caps and cytoplasmic granules, and their smooth endoplasmic reticulum (SER) expanded.
Later Developments
- Near the 12-hour mark, the Clara cells exhibited signs of deterioration, necrosis, and exfoliation. Bronchiolar ciliated cells also started displaying evidence of degeneration and necrosis.
- 24 hours after 3MI ingestion, sparse epithelial cells with an enlarged SER began to appear on the revealed basal lamina.
Continued Impact and Inflammation
- Beyond a day post-ingestion, between 3 to 6 days, various cells such as inflammatory and epithelial cells, along with fibroblast-like cells, collagen, and debris began to obstruct numerous bronchiolar lumens.
- This reorganization resulted in a more streamlined columnar bronchiolar epithelium with reasonably usual ciliated cells and a reduced quantity of fibroblast-like cells.
Long-Term Changes
- Despite almost a month (27 days) having passed since the intake of 3MI, mature Clara cells were scarce, and bronchiolar lumens remained segmented by collagenous bands.
- This study confirms the endurance of 3MI toxicity, establishing it as a durable model of equine bronchiolitis, with many morphological attributes being reminiscent of the spontaneous illness.
Cite This Article
APA
Turk MA, Breeze RG, Gallina AM.
(1983).
Pathologic changes in 3-methylindole-induced equine bronchiolitis.
Am J Pathol, 110(2), 209-218.
Publication
Researcher Affiliations
MeSH Terms
- Animals
- Bronchial Diseases / chemically induced
- Bronchial Diseases / pathology
- Bronchial Diseases / veterinary
- Epithelium / ultrastructure
- Horse Diseases / chemically induced
- Horses
- Microscopy, Electron
- Microscopy, Electron, Scanning
- Pulmonary Alveoli / ultrastructure
- Skatole
References
This article includes 18 references
- Foley FD, Lowell FC. Equine centrilobular emphysema. With further observations on the pathology of heaves.. Am Rev Respir Dis 1966 Jan;93(1):17-21.
- Carlson JR, Dyer IA, Johnson RJ. Tryptophan-induced intersitial pulmonary emphysema in cattle.. Am J Vet Res 1968 Oct;29(10):1983-9.
- Wang NS, Huang SN, Sheldon H, Thurlbeck WM. Ultrastructural changes of Clara and type II alveolar cells in adrenalin-induced pulmonary edema in mice.. Am J Pathol 1971 Feb;62(2):237-52.
- Carlson JR, Yokoyama MT, Dickinson EO. Induction of pulmonary edema and emphysema in cattle and goats with 3-methylindole.. Science 1972 Apr 21;176(4032):298-9.
- Huang TW, Carlson JR, Bray TM, Bradley BJ. 3-methylindole-induced pulmonary injury in goats.. Am J Pathol 1977 Jun;87(3):647-66.
- McPherson EA, Lawson GH, Murphy JR, Nicholson JM, Fraser JA, Breeze RG, Pirie HM. Chronic obstructive pulmonary disease (COPD): identification of affected horses.. Equine Vet J 1978 Jan;10(1):47-53.
- Breeze R, Lee H, Grant BD. Toxic lung disease.. Mod Vet Pract 1978 Apr;59(4):301.
- Evans MJ, Cabral-Anderson LJ, Freeman G. Role of the Clara cell in renewal of the bronchiolar epithelium.. Lab Invest 1978 Jun;38(6):648-53.
- Bradley BJ, Carlson JR, Dickinson EO. 3-methylindole-induced pulmonary edema and emphysema in sheep.. Am J Vet Res 1978 Aug;39(8):1355-8.
- Breeze RG. Heaves. The problem of disease definition.. Vet Clin North Am Large Anim Pract 1979 May;1(1):219-30.
- Boyd MR, Statham CN, Longo NS. The pulmonary clara cell as a target for toxic chemicals requiring metabolic activation; studies with carbon tetrachloride.. J Pharmacol Exp Ther 1980 Jan;212(1):109-14.
- Bray TM, Carlson JR. Role of mixed-function oxidase in 3-methylindole-induced acute pulmonary edema in goats.. Am J Vet Res 1979 Sep;40(9):1268-72.
- Boyd MR. Biochemical mechanisms in chemical-induced lung injury: roles of metabolic activation.. Crit Rev Toxicol 1980 Aug;7(2):103-76.
- Hanafy MS, Bogan JA. The covalent binding of 3-methylindole metabolites to bovine tissue.. Life Sci 1980 Sep 29;27(13):1225-31.
- Plopper CG, Mariassy AT, Hill LH. Ultrastructure of the nonciliated bronchiolar epithelial (Clara) cell of mammalian lung: I. A comparison of rabbit, guinea pig, rat, hamster, and mouse.. Exp Lung Res 1980 Jun;1(2):139-54.
- Plopper CG, Hill LH, Mariassy AT. Ultrastructure of the nonciliated bronchiolar epithelial (Clara) cell of mammalian lung. III. A study of man with comparison of 15 mammalian species.. Exp Lung Res 1980 Jun;1(2):171-80.
- LUFT JH. Improvements in epoxy resin embedding methods.. J Biophys Biochem Cytol 1961 Feb;9(2):409-14.
- THURLBECK WM, LOWELL FC. HEAVES IN HORSES.. Am Rev Respir Dis 1964 Jan;89:82-8.
Citations
This article has been cited 3 times.- Woods LW, Wilson DW, Schiedt MJ, Giri SN. Structural and biochemical changes in lungs of 3-methylindole-treated rats.. Am J Pathol 1993 Jan;142(1):129-38.
- Atwal OS, Persofsky MS. Ultrastructural changes in intraacinar pulmonary veins. Relationship to 3-methylindole-induced acute pulmonary edema and pulmonary arterial changes in cattle.. Am J Pathol 1984 Mar;114(3):472-86.
- Richards RJ, Oreffo VI, Lewis RW. Clara cell cultures from the mouse and their reaction to bronchiolar toxins.. Environ Health Perspect 1990 Apr;85:119-27.
Use Nutrition Calculator
Check if your horse's diet meets their nutrition requirements with our easy-to-use tool Check your horse's diet with our easy-to-use tool
Talk to a Nutritionist
Discuss your horse's feeding plan with our experts over a free phone consultation Discuss your horse's diet over a phone consultation
Submit Diet Evaluation
Get a customized feeding plan for your horse formulated by our equine nutritionists Get a custom feeding plan formulated by our nutritionists
