Beneficial effects of Etanercept on experimental necrotizing enterocolitis.

PURPOSE: Tissue damage in necrotizing enterocolitis (NEC) of infants occurs as a result of an uncontrolled inflammatory response. The aim of this study was to investigate any potential anti-inflammatory effects that Etanercept may have on the inflammatory response in an experimental NEC model in newborn rats. METHODS: Newborn pups were randomized into three groups immediately after birth (Control, NEC + Placebo and NEC + Etanercept). Pups in the NEC + Placebo and NEC + Etanercept groups were subjected to an NEC-inducing protocol (hypercarbia, hypothermia and hyperoxia) twice a day for 3 days. Pups in the NEC + Etanercept group were given an intraperitoneal injection of Etanercept. Rats were harvested for biochemical and histopathological examinations. RESULTS: The histopathological injury score of rats in the NEC + Placebo group was significantly higher compared to the NEC + Etanercept and Control groups (p < 0.05 for both comparisons). Tissue levels of tumor necrosis factor-α, interleukin-1ß, and malondialdehyde were higher in the placebo group compared to the Etanercept group. CONCLUSION: Our results suggest that Etanercept attenuates intestinal tissue damage in NEC by reducing inflammation and blocking the production of free-oxygen radicals, while also reducing tissue levels of tumor necrosis factor-α and interleukin-1ß.

All-trans-retinoic acid attenuates intestinal injury in a neonatal rat model of necrotizing enterocolitis.

BACKGROUND: Ischemia/reperfusion-induced intestinal injury is mediated by reactive oxygen species and inflammatory mediators. OBJECTIVES: This study was designed to evaluate whether all-trans-retinoic acid (ATRA) administration can attenuate intestinal injury and to analyze the antioxidant and anti-inflammatory effects of ATRA in a neonatal rat model of necrotizing enterocolitis (NEC). METHODS: Twenty-nine Wistar albino rat pups were randomly divided into 3 groups: group 1 = control, group 2 = NEC and saline, and group 3 = NEC and ATRA treatment. NEC was induced by hyperosmolar enteral formula feeding and exposure to hypoxia after cold stress at +4°C and oxygen. Pups in group 3 were injected intraperitoneally with ATRA (0.5 mg/kg body weight) once a day prior to each NEC procedure, beginning on postnatal day 1 and daily through postnatal day 4. The pups were killed on the 4th day and their intestinal tissues were harvested for biochemical and histopathological analysis. RESULTS: Mucosal injury scores and intestinal malondialdehyde levels in group 2 were found to be significantly higher than other groups (p < 0.05). Intestinal superoxide dismutase and glutathione peroxidase activities in group 3 were significantly higher than group 2 (p = 0.04 and p = 0.04, respectively). Intestinal tissue tumor necrosis factor-α levels were significantly reduced with ATRA treatment in group 3 compared to group 2 (p < 0.001). CONCLUSIONS: It is likely that oxidative stress and inflammatory mediators contributed to the pathogenesis of NEC and that ATRA had a protective effect on intestinal injury through its anti-inflammatory and antioxidant properties.

Protective effects of colchicine in an experimental model of necrotizing enterocolitis in neonatal rats.

BACKGROUND: The pathophysiology of necrotizing enterocolitis (NEC) includes the massive production of endogenous cytokines with exaggerated activation of inflammatory pathways. Colchicine has been used as an anti-inflammatory agent. The aim of this study was to investigate the possible beneficial effects of colchicine in a neonatal rat model of NEC. MATERIALS AND METHODS: We randomly divided rat pups into three groups: a control group, a saline-treated NEC group, and a colchicine-treated NEC group. We induced NEC by hyperosmolar enteral formula feeding and exposure to hypoxia/reoxygenation after cold stress. Intestinal samples were harvested for biochemical and histopathologic analyses. RESULTS: The grade of intestinal injury of pups in the saline-treated NEC group was significantly higher than in the control and colchicine-treated groups (P < 0.001 and 0.003, respectively). The median level of intestinal malondialdehyde was significantly higher in the saline-treated NEC group compared with the control group (P = 0.006) or the colchicine-treated NEC group (P = 0.015). We observed significantly higher activity levels of intestinal superoxide dismutase and glutathione peroxidase in the colchicine-treated NEC group compared with the saline-treated NEC group (P = 0.033 and 0.030, respectively). The tissue levels of tumor necrosis factor-α and interleukin-1ß were significantly higher in the saline-treated NEC group compared with the colchicine-treated NEC group (P < 0.001 and 0.003, respectively). CONCLUSIONS: We observed that in this model of NEC, colchicine had favorable effects on intestinal histologic and biochemical changes.

Antioxidant effects of N-acetylcysteine in a neonatal rat model of necrotizing enterocolitis.

BACKGROUND/PURPOSE: Hypoxia and ischemia appear to play an important role in the pathogenesis of necrotizing enterocolitis (NEC), which may be related to oxygen-derived free radical formation. This study was designed to evaluate the role of oxidative stress and potentially beneficial effects of N-acetylcysteine (NAC) in a neonatal rat model of NEC. METHODS: Thirty Wistar albino rat pups were randomly divided into 3 groups: group 1, control; group 2, NEC and saline; and group 3, NEC and NAC treatment. Necrotizing enterocolitis was induced by hyperosmolar enteral formula feeding and exposure to hypoxia after cold stress at 4°C and oxygen. The pups were killed on the fourth day, and their intestinal tissues were harvested for biochemical and histopathologic analysis. RESULTS: Mucosal injury scores and intestinal malondialdehyde levels in group 2 were found to be significantly higher than that in other groups (P ≤ .05). Intestinal superoxide dismutase activities in group 3 were significantly higher than that in group 2 (P = .018). Intestinal tissue tumor necrosis factor α levels were significantly reduced with NAC treatment in group 3 compared with group 2 (P < .003). CONCLUSIONS: It is likely that oxidative stress and inflammatory mediators contribute to the pathogenesis of NEC and that NAC has a protective effect on intestinal injury through its antiinflammatory and antioxidant properties.