Abstract:

BACKGROUND: Acute pancreatitis (AP) is an inflammatory disease characterized by pancreatic autodigestion and systemic inflammatory responses, which can lead to severe complications and high mortality. Hypothermia has shown potential protective effects against AP-related injury; however, the metabolic mechanisms underlying hypothermia-mediated protection against AP remain unclear. In this study, we aimed to investigate serum metabolic changes in a rat model of AP treated with hypothermia with intragastric cooling and to identify potential protective metabolites and explore their biological roles.

METHODS: The entire study included both in vivo and in vitro experiments. In the in vivo experiments, 18 male Sprague Dawley rats were randomly assigned to three groups (n=6 per group): the sham operation (SO), AP, and AP treated with hypothermia (APH) groups. AP was induced by retrograde intraductal injection of 3.5% sodium taurocholate. In the APH group, hypothermia with intragastric cooling (25-27 °C) was achieved using a gastric cooling balloon, while the rectal temperature was maintained at physiological levels. Serum amylase levels, pancreatic histopathology, and inflammatory cytokine expression were assessed using an enzyme-linked immunosorbent assay, Schmidt scoring system, immunohistochemistry, and Western blotting. Gas chromatography-mass spectrometry (GC-MS)-based metabolomics was performed to identify differentially expressed serum metabolites associated with hypothermia. Through in vitro experiments, the biological effects of key metabolites were further investigated in sodium taurocholate-treated AR42J pancreatic acinar cells.

RESULTS: In vivo, serum amylase levels, pancreatic pathological injury, and the expression of inflammatory cytokines, including interleukin-6 (IL-6), tumor necrosis factor α (TNF-α), and nuclear factor-κB (NF-κB), were significantly lower in the APH group than in the AP group. GC-MS metabolomic profiling revealed 41 differentially expressed metabolites between the APH and AP groups. In vitro experiments demonstrated that LY294002, pinitol, tocopherol and their combination reduced reactive oxygen species production, decreased α-amylase activity, and modulated Nrf2 mRNA expression in AR42J cells.

CONCLUSION: In this study, local hypothermia attenuated inflammatory cytokine release, serum amylase elevation, and pancreatic injury in a rat model of AP. These protective effects may be associated with the upregulation of serum pinitol and tocopherol levels. These metabolites may exert potential protective effects through pathways related to inflammation and oxidative stress.

Key words: Acute pancreatitis, Hypothermia, Pinitol, Tocopherol