Abstract Walker-256 tumor is an experimental model known to promote cachexia syndrome, oxidative stress, and systemic inflammation. This study evaluated the duodenal mucosa of rats with Walker-256 tumor administered with 1% l-glutathione, intending to evaluate the damage caused by cancer-associated cachexia in the gastrointestinal tract and the effects of antioxidant administration on mucosal protection. Twenty-four 55-day-old male Wistar rats were distributed into four groups: control (C); control administered with 1% l-glutathione (C-GSH); Walker-256 tumor (W) and Walker-256 tumor administered with 1% l-glutathione (W-GSH). After 14 days of treatment, the duodenum was harvested for morphometric analysis of the mucosa, proliferation, apoptosis, immunostaining of varicosities immunoreactive (IR) to vasoactive intestinal peptide (VIP) and 5-HT-IR cells, and quantification of mast cells and goblet cells. Walker-256 tumor-bearing rats showed cachexia syndrome, mucosal atrophy, reduced cell proliferation, reduced 5-HT-IR cells, and increased goblet cells and VIPergic varicosities, which were not reversed by l-glutathione. On the other hand, l-glutathione caused a reduction of cells in apoptosis and mast cell recruitment, demonstrating a partial recovery of the damage detected in the intestinal mucosa.
