Abstract
Necrotizing enterocolitis (NEC) is a life-threatening inflammatory disease of preterm infants, increasingly viewed as a cytokine-driven disorder of the immature intestine. We aimed to characterize local peritoneal concentrations of interleukin (IL)-1β, IL-6 and tumor necrosis factor-α (TNF-α) in a standardized neonatal rat NEC model and relate them to histopathological injury. Seventy-four SPRD/Mol/Lodz rat pups were allocated to a control group (CTRL; n = 12) or subjected to a hypoxia-hypothermia-formula-feeding NEC protocol (NEC; n = 62). After 72 h, small-intestinal samples were scored using a four-tier NEC scale (0-3), and peritoneal fluid cytokine levels were measured by ELISA. All CTRL animals exhibited normal histology (grade 0), whereas NEC pups showed a wide spectrum of lesions, with 66.6% classified as grade 2-3 and a significantly higher mean NEC score in NEC than CTRL (p < 0.001). Peritoneal IL-1β and TNF-α concentrations were markedly elevated in NEC versus CTRL animals (both p < 0.001), while IL-6 levels showed no statistically significant between-group difference. These findings indicate that experimental NEC in this model is accompanied by a pronounced local pro-inflammatory response dominated by IL-1β and TNF-α, whereas IL-6 may follow distinct temporal or compartment-specific kinetics. Peritoneal cytokine profiling may help refine mechanistic understanding and guide future biomarker and immunomodulatory strategies in NEC.