Abstract

Background:
Euphrates jerboa is a desert-adapted animal that survives in extreme arid conditions in Iraq and other countries. This might be due to specialized gastrointestinal (GI) adaptations that allow this animal to survive hard conditions.

Aim:
This study aimed to investigate the morphological, histochemical, and molecular features of the esophagus, stomach, and duodenum.

Methods:
Traditional histomorphology, histochemistry, and real-time polymerase chain reaction targeting the MUC17 gene were conducted

Results:
Morphometry revealed a short esophagus, a J-shaped stomach, and an elongated duodenum, indicating adaptations for processing a dry, fibrous diet. Histochemistry results exhibited region-specific mucin scattering. In particular, neutral mucins dominated gastric surface cells of the stomach and duodenal Brunner’s glands of the duodenum, whereas acidic mucins were abundant in the esophageal submucosal glands of the esophagus and gastric neck cells of the stomach. RT-qPCR revealed higher MUC17 gene expression in the stomach than in the esophagus and duodenum (p=0.009), representing a stomach-specific role for this membrane-bound mucin.

Conclusion:
The results indicated that in the GI of jerboa, more mucin secretion and different expression status of MUC17 were recruited to reinforce its mucosal barrier combined with lubrication and water conservation for jerboa against extreme aridity conditions in deserts. This integrated strategy uncovers major evolutionary adaptations involved in aridity survival and establishes the jerboa as a new model to investigate mucosal resilience and mucin-related diseases.

Key words: Desert adaptation; Gastrointestinal tract; MUC17; Mucosal defense; RT-Qpcr.