Inhibition of endoplasmic reticulum stress by 4-phenylbutyric acid prevents vital organ injury in rat acute pancreatitis

This study was conducted to investigate the effect of 4-phenylbutyric acid (4-PBA) on vital organ injury following sodium taurocholate-induced acute pancreatitis (AP) in rats and the pertinent mechanism. The serum biochemical indicators and key inflammatory cytokines, histopathological damage and apoptosis of vital organs in rat AP, were evaluated in the presence or absence of 4-PBA. Moreover, mRNA and protein levels of endoplasmic reticulum stress (ERS) markers were assessed. 4-PBA significantly attenuated the structural and functional damage of vital organs, including serum pancreatic enzymes, hepatic enzymes, creatinine, and urea. The morphological changes and infiltration of neutrophils and macrophages were reduced as well. These effects were accompanied by decreased serum levels of proinflammatory TNF-α and IL-1β. Furthermore, 4-PBA diminished the expression of ERS markers (glucose-regulated protein 78, CCAAT/enhancer-binding protein homologous protein, protein kinase R-like ER kinase, activated transcription factor 6, and type-1 inositol requiring enzyme) in vital organs of AP rats. 4-PBA also reduced AP-induced apoptosis in lung, liver, and kidney tissues as shown by TUNEL assay. The present study demonstrated that 4-PBA protected pancreas, lung, liver, and kidney from injury in rat AP by regulating ERS and mitigating inflammatory response to restrain cell death and further suggested that 4-PBA may have potential therapeutic implications in the disease. NEW & NOTEWORTHY In this study, we suggest that endoplasmic reticulum stress (ERS) is an important player in the development of acute pancreatitis-induced multiorgan injury, providing additional evidence for the proinflammatory role of ERS. Because 4-phenylbutyric acid has been suggested to inhibit ERS in many pathological conditions, it is possible that this effect can be involved in alleviating inflammatory response and cell death to ameliorate vital organ damage following acute pancreatitis induced by sodium taurocholate in rats.