Sodium formate induces development-dependent intestinal epithelial injury via necroptosis and apoptosis

ObjectivesNecrotizing enterocolitis (NEC) is a common and sometimes fatal disease affecting premature infants. Elevated formate has been found in the stool of patients with NEC. Sodium formate (NaF) is used to explore the role of formate in the intestinal epithelial injury.MethodsIn this study, 150 mM NaF solution was intraluminally injected in 14-day-old and 28-day-old mice. Mice were sacrificed after 24 h of feces collection, and the blood and small intestinal tissues were collected to detect the pathological damage of intestinal tissue, intestinal permeability, oxidative stress indicators including SOD, HO-1, MDA, and 4-HNE, inflammatory cytokines including IL-1 beta, TNF-alpha and IL-6, mitochondrial function such as ATP and PGC-1 alpha in mice intestinal tissue, indicators of the cell death modes including necroptosis-related protein RIPK1 and p-MLKL, and apoptosis- related protein cleaved-caspase-3 and p-AKT (S473).ResultsNaF treatment significantly damaged intestinal epithelial tissue and barrier function, caused mitochondrial dysfunction, manifesting as decreased ATP and PGC-1 alpha levels, increased lipid peroxidation products MDA and 4-HNE, depleted antioxidant enzyme SOD, and upregulated the expression of HO-1. Furthermore, NaF treatment induced inflammatory responses by promoting the release of IL-1 beta, IL-6 and TNF-alpha in a development-dependent manner, eventually inducing necroptosis and apoptosis.ConclusionsFormate may be a source of metabolic intestinal injury contributing to the pathogenesis of NEC in human newborns.