Ulinastatin relieves sepsis-associated dysmotility via IL-1β-related enteric neuroprotection.

Abstract

OBJECTIVE: To evaluate the comprehensive protective effects of ulinastatin (UTI) on intestinal structure and function during sepsis and to explore whether UTI restores intestinal motility through mechanisms involving attenuation of interleukin-1β (IL-1β)-mediated inflammation. METHODS: A murine cecal ligation and puncture (CLP) model was established and mice received intravenous UTI. Primary outcomes included 7-day survival, time to first black stool, fecal output, small-intestinal transit, and blinded histopathology. Barrier integrity was assessed by Alcian Blue-Periodic Acid-Schiff staining for goblet-cell mucin and Claudin-1 immunofluorescence; inflammation by IL-1β, tumor necrosis factor (TNF)-α, and IL-6; and enteric nerve integrity by counting HuD-positive neurons and measuring PGP9.5-labeled nerve fibers. To assess direct effects, primary enteric neurons were stimulated with lipopolysaccharide or IL-1β in vitro. An IL-1β-neutralizing antibody (nAb) was used alone or with UTI to interrogate mechanism. RESULTS: UTI improved survival, shortened stool latency, increased pellet output, and enhanced transit after CLP. UTI attenuated intestinal injury, restored goblet-cell mucin production and Claudin-1 expression, and reduced systemic and colonic IL-1β, TNF-α, and IL-6. Moreover, UTI also increased the number of HuDenteric neurons and preserved PGP9.5-labeled nerve fiber networks. In vitro, UTI preserved βIII-tubulin-defined neuronal morphology and reduced IL-1β secretion. IL-1β nAb reproduced the protective benefits on enteric nerve and intestinal motility; no significant additive benefits were observed when IL-1β nAb was combined with UTI. CONCLUSION: UTI confers broad and integrated protection of the intestine during sepsis. These findings suggest that IL-1β-mediated inflammatory signaling plays a key role in UTI-induced enteric neuroprotection and restoration of intestinal motility.