Strain-dependent duodenal structural alterations in hamsters infected with Leishmania (Viannia) braziliensis

Leishmania (Viannia) braziliensis (LVB), the main etiological agent of cutaneous and mucocutaneous leishmaniasis, may cause atypical manifestations in immunosuppressed hosts, affecting organs beyond the skin, including the intestine. This study investigated whether the duodenum is involved during experimental LVB infection in hamsters. Overall, 48 female golden hamsters were divided into a control and infected group with five LVB strains. They were euthanized after 90 or 120 days of infection. Duodenal samples were subjected to histological and morphometric analyses, including evaluation of the duodenal wall, villi dimensions, intraepithelial lymphocytes, goblet cells, mast cells, collagen fiber composition (types I and III), and myenteric ganglia. Biochemical assays were performed to assess myeloperoxidase activity and nitrite levels. LVB infection reduced Alcian Blue pH 1.0-positive goblet cells and myenteric ganglia area at 90 days and increased type III collagen fibers at 120 days. Infected animals showed increased villus width at 90 days and greater villus height at 120 days. Overall, LVB infection induces significant and time-dependent alterations in the duodenal histoarchitecture, including epithelial, neuronal, and extracellular matrix changes, indicating that the duodenum undergoes dynamic structural remodeling during the infection.