Tumor necrosis factor α1 decreases mucosal immune and antioxidant response in the midgut of hybrid fish (white crucian carp ♀ x red crucian carp ♂)

Tumor necrosis factor alpha 1 (TNF alpha) is a pleiotropic cytokine involved in immune regulation and cellular homeostasis, but the crucial role of TNF alpha in fish gut remained unclear. The current study aimed to evaluate the immunoregulatory function of TNF alpha 1 on gut barrier in a novel hybrid fish (WR), which was produced by crossing white crucian carp (Carassius cuvieri, female ) with red crucian carp (Carassius auratus red var, male ). In this study, WR-tnf alpha 1 sequence was identified, and a high-level expression was detected in the intestine. Elevated levels of WR-tnf alpha 1 expressions were detected in immune-related tissues and cultured fish cells on stimulation. The appearance of vacuolization and submucosal rupture was observed in TNF alpha 1-treated midgut of WR, along with elevated levels of goblet cell atrophy, whereas no significant changes were detected in most expressions of tight-junction genes and mucin genes. In contrast, WR receiving gut perfusion with WR-TNF alpha 1 showed a remarkable decrease in antioxidant status in midgut, whereas the expression levels of apoptotic genes and redox responsive genes increased sharply. These results suggested that TNF alpha 1 could exhibit a detrimental effect on antioxidant defense and immune regulation in the midgut of WR.