Histological and Histochemical Examination of Mucous Cells in Esophagus and Stomach of Rattus norvegicus

Aims Norway rat (Rattus norvegicus) as a laboratory animal is one of the most popular experimental models for research, which has a similar anatomical structure of the body organs compared to a human. This study aimed at histological and histochemical examination of mucous cells in the esophagus and stomach of Norway rats. Materials & Methods In this experimental study, ten healthy adult male rats (R. norvegicus) were anesthetized using an overdose of chloroform and samples were taken from the esophagus and stomach. The tissues were then excised and fixed with 10% formalin for histological and histochemical studies. Findings Light microscopic observations on sections of the esophagus showed walls consisting of four layers; mucosa, submucosa, muscular and adventitia layer or serosa. The surface layer of the epithelium reacted strongly to PAS staining, but the rest of the epithelium had a moderate reaction to PAS in all regions of the esophagus. The submucosa showed a weak reaction to PAS in all regions of the esophagus. The muscularis layer in the cervical, thoracic, and abdominal esophagus regions reacted moderately to PAS; however, the serosa showed a weakly reaction to PAS in cervical, thoracic and abdominal regions. Conclusion Recognizing the anatomical and histochemical features of different small mammalians as the models of laboratory animals for testing drug absorbance can help understand the probable results in human patients.