Hydrogen Sulfide Improves Outcomes in a Murine Model of Necrotizing Enterocolitis via the Cys440 Residue on Endothelial Nitric Oxide Synthase

Abstract

Background: Hydrogen sulfide (H₂S) has been shown to improve outcomes in a murine model of necrotizing enterocolitis (NEC). There is evidence in humans that H₂S relies on endothelial nitric oxide synthase (eNOS) to exert its protective effects, potentially through the persulfidation of eNOS at the Cysteine 443 residue. We obtained a novel mouse strain with a mutation at this residue (eNOS^C440G) and hypothesized that this locus would be critical for GYY4137 (an H₂S donor) to exert its protective effects.

Methods: Necrotizing enterocolitis was induced in 5-day old wild type (WT) and eNOS^C440G mice using intermittent exposure to hypoxia and hypothermia in addition to gavage formula feeds. On postnatal day 9, mice were humanely euthanized. Data collected included daily weights, clinical sickness scores, histologic lung injury, intestinal injury (macroscopically and histologically), and intestinal perfusion. During the NEC model, pups received daily intraperitoneal injections of either GYY4137 (50 mg/kg) or PBS (vehicle). Data were tested for normality and compared using t-test or Mann-Whitney, and a p-value <0.05 was considered significant.

Results: In WT mice, the administration of GYY4137 significantly improved clinical sickness scores, attenuated intestinal and lung injury, and improved mesenteric perfusion compared to vehicle (p < 0.05). In eNOS^C440G mice, the treatment and vehicle groups had similar clinical sickness scores, intestinal and lung injury scores, and intestinal perfusion.

Conclusions: GYY4137 administration improves clinical outcomes, attenuates intestinal and lung injury, and improves perfusion in a murine model of necrotizing enterocolitis. The beneficial effects of GYY4137 are dependent on the Cys440 residue of eNOS.

Keywords: Hydrogen sulfide; Necrotizing enterocolitis; Nitric oxide; Persulfidation; eNOS.