Maternal N‐Acetyl‐Cysteine prevents neonatal brain injury associated with necrotizing enterocolitis in a rat model

Introduction Preterm infants with necrotizing enterocolitis (NEC) are at increased risk for cerebral injury and neurodevelopmental dysfunction. N-acetyl-cysteine (NAC) is a known anti-inflammatory and antioxidant agent. Currently, there is no prophylactic treatment in clinical use to prevent NEC and its neurodevelopmental sequelae. We sought to determine whether brain inflammation/apoptosis accompanies NEC systemic inflammation, and whether it can be attenuated by maternal NAC treatment during pregnancy and/or in the neonatal period in a rat model. Material and methods An established NEC newborn model (hypoxia 5% O2 for 10 min and formula feeding thrice daily, beginning on day 1 for 4 days) was used in Sprague-Dawley rat pups (n=32). An additional group of pups (n=33) received NAC (300mg/kg intraperitoneal thrice daily) in addition to NEC conditions (NEC-NAC). Control pups (n=33) were nursed and remained with the dam in room air. Two additional groups included pups of dams treated once daily with NAC (300mg/kg intravenous) in the last 3 days of pregnancy. After birth, pups were randomized into NAC-NEC (n=33) with NEC conditions or NAC-NEC-NAC (n=36) with additional postnatal NAC treatment. Pups were sacrificed on the fifth day of life. Pups serum IL-6 protein levels, and brain NFkB p65, neuronal nitric oxide synthase (nNOS), Caspase 3, TNF-α, IL-6 and IL-1β protein levels were determined by ELISA, Western blot, and TUNEL staining, and compared between the groups by ANOVA. Results NEC pups had significantly increased serum IL-6 levels compared to the control group as well as increased neuronal apoptosis and brain protein levels of NFkB, nNOS, Caspase 3, TNFα, IL-6 and IL-1β compared to control. In all NAC treatment groups, levels of serum IL-6, neuronal apoptosis and brain NFkB, nNOS, Caspase 3, TNF-α, IL-6 and IL-1β protein levels were significantly reduced compared to NEC group. The most pronounced decrease was demonstrated within the NAC-NEC-NAC group CONCLUSIONS: NAC treatment can attenuate newborn inflammatory response syndrome and decrease offspring brain neuro apoptosis and inflammation in a rat model of NEC by inhibition of NFkB, nNOS and Caspase 3 pathways.