Cytopathological characteristics for provoked lesions of squamous epithelia of the digestive system in animal models

Abstract

Relevance: Noticeable spreading of malignant neoplasms of the upper section of the digestive system and the worsening of these patients’ quality of life in case of late diagnostics stimulate the development of protocols for early detection of precancerous changes.
 The purpose of the study was to investigate the morphological characteristics of changes in the squamous epithelium of the upper part of the digestive tube in model organisms under provoked carcinogenesis when exposed to substances with proven carcinogenic activity.
 Methods: 40 female nonlinear white rats from the Orekhovo-Zuevsky urban settlement veterinary station were used as model organisms. The rats were divided into four equal groups. The first control group was not exposed to any specific influences. In groups 2-4, the rats underwent sedation and mechanical scarification microtraumatization of the oral mucosa. Then, they were applied twice a week by 0.9% NaCl solution (control group 2), 1% aqueous solution of dimethyl sulfoxide (DMSO, Akrikhin, Russia) (control group 3), or 1% aqueous solution of DMSO containing 0.1 mg/ml 4-nitroquinoline-N-oxide (4-NQO, Acros Organics, USA) (Experimental Group 4).
 Results: The cytological picture associated with chronic trauma to the mucous membrane of the upper digestive tract was characterized by nonspecific reactions: inflammation, hyper- and parakeratosis, and atrophic changes. There were no statistically significant differences in the frequency of such changes between the experimental and control groups. Specific changes in squamous epithelium towards a precancerous state in the Experimental Group with chronic exposure to a substance with carcinogenic activity occurred significantly more often than in the control groups (p <0.05), as proven by the results of comparative histological verification. Conclusion: Cytological study could be used in clinical practice as a screening tool for precancerous oropharynx and upper esophagus conditions.