Morphological characteristics of changes in the
 squamous epithelium of the upper part of the
 digestive tract in model organisms in the settings
 of provoked carcinogenesis

Abstract

Relevance: Noticeable spreading of malignant neoplasms of upper section of 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 obtained from the Orekhovo-Zuevsky urban settlement veterinary station were used as model
 organisms. The rats were divided into 4 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 can be offered for clinical study as
 a screening tool for precancerous oropharynx and upper esophagus
 conditions