Ustenko J.U., Gushchin Y.A. A review of the most common pathologies of the stomach in laboratory animals in preclinical studies of drugs. Laboratory Animals for Science. 2020; 2. https://doi.org/10.29296/2618723X-2020-02-02
Pathomorphological analysis is an integral part of preclinical studies. It allows evaluating the pathological changes that occur in the organs of laboratory animals at macroscopic and microscopic levels. Gastric pathology can develop due to the local irritating effect of the test articles during peroral and intragastric administration, as a spontaneous or background pathology, due to various mechanisms with other routes of administration (intramuscular, subcutaneous, intraperitoneal and others). The classification and morphological criteria of gastric pathology in laboratory animals are most fully developed by the INHAD group for rats and mice. Clear recommendations have not been developed for other animal species yet. Orientation of toxic pathologists to a unified classification will be avoiding confusion in interpretations, will be ensuring reproducibility of results, and will allow comparing of the results of various researchers. А possible classification of gastric pathologies in laboratory animals in preclinical studies is presented in the article. It is based on an analysis of literary sources. Congenital pathologies such as squamous cysts and ectopic tissues are described.
Atrophic and hypertrophic changes in the mucous membrane; metaplastic changes; dystrophic changes, such as vacuolization; detection of eosinophilic globules, mineralization, amyloidosis; the formation of glandular cysts and diverticulum in the epithelium of the stomach are considered. Аpplication of additional microscopic examination techniques described: immunohistochemical staining for TFF2, CDX1 and CDX2 for differentiation of metaplastic shifts; Congo red stained to verify the diagnosis of amyloidosis. Apoptosis and necrosis of а stomach epithelium are also described in detail. Since these processes are indistinguishable during the evaluating routine sections stained with hematoxylin-eosin, additional methods (transmission electron microscopy, DNA-laddering, TUNEL, immunohistochemistry for caspases, (in particular, caspase-3) are listed. They allow to accurately differentiate apoptosis and necrosis. Inflammatory changes are described: inflammatory infiltrate and inflammation. А gastric dilatation, volvulus, detection of trichobesoars in the lumen of the stomach also are considered. For each pathology, an illustration, a brief macroscopic and microscopic characteristic is given. Possible causes of stomach pathologies in rats, mice, hamsters, gerbils, ferrets, rabbits, dwarf pigs in preclinical studies are described.
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Authors contribution:
Zh. Ustenko – literature analysis, writing the article, editing the article, providing of the photo materials.
Ya. Gushchin – idea of the research, editing the article, providing of the photo materials.
Acknowledgements. The study was performed without external funding.