Use of combined eosin and methylene green staining for the selective detection of eosinophilic granulocytes in the gastrointestinal mucosa

BACKGROUND: Eosinophilic granulocytes exhibit antibacterial, antiparasitic, and antiviral activity and play a significant role in the pathogenesis of diseases such as eosinophilic esophagitis and colitis. However, standard methods for their identification have significant limitations, which complicate precise quantification and diagnosis of associated conditions. AIM: To develop and evaluate a novel staining method for accurate and selective identification of eosinophilic granulocytes in the gastrointestinal tract tissues. METHODS: The study was conducted using histological sections of the stomach, small intestine, and large intestine from male Wistar rats (n = 16). Tissue sections were stained with a combination of eosin and methylene green. RESULTS: The developed method provided high-contrast staining of eosinophilic granulocytes and demonstrated greater accuracy compared to conventional hematoxylin and eosin staining. Eosinophils were distinctly visible on slides stained with the new method even under low magnification. The technique enabled easy identification, enumeration, and localization of eosinophilic granulocytes within the gastrointestinal tract tissues. CONCLUSION: The proposed staining method allows for precise and selective detection of eosinophilic granulocytes in the gastrointestinal mucosa of rats and shows promise for use in diagnosing conditions associated with eosinophilic infiltration.