The Effects of Da-Chai-Hu Decoction Alleviating Pancreatic Exocrine Dysfunction by Inhibiting Endoplasmic Reticulum Stress of Acinar Cell in Mice with Chronic Pancreatitis

Background: Chronic pancreatitis (CP) is characterized by significant pancreatic exocrine dysfunction, with limited targeting therapeutic strategies. It has been reported that DCHD can effectively alleviate pancreatic injury in chronic pancreatitis; however, its effect and mechanism on pancreatic exocrine dysfunction remain unclear.

Objective: To investigate the therapeutic effects of Da-Chai-Hu Decoction (DCHD) on pancreatic exocrine dysfunction in CP and explore its underlying mechanisms.

Methods: Thirty male C57BL/6 mice were divided into control, CP model, and three DCHD dose groups (11, 22, 44 g/kg). CP was induced via repeated caerulein injections (50 μg/kg), followed by 3 weeks of DCHD treatment. Histopathological analysis of pancreatic tissue (via HE staining, IHC, IF), molecular assays (Western blot, RT-PCR), and RNA-seq were performed. LC-MS/MS identified chemical components in the serum of DCHD-treated mice, and network pharmacology predicted potential targets. Mouse pancreatic acinar cells (266-6) exposed to caerulein and PI3K Inhibitor LY294002 were treated with DCHD serum to validate pathways.

Results: DCHD not only alleviated pancreatic fibrosis (α-SMA) and inflammation (IL-6), but also maintained the level of Amylase. RNA-seq revealed that DCHD treatment downregulated the expression of genes related to inflammation, fibrosis, Apoptosis, and ERS. The bioactive compounds in DCHD serum were identified by LC-MS/MS, and further were linked to PI3K/Akt and ERS pathway through network pharmacology. In vivo validation experiment showed that the expression of PI3K/Akt pathway and ERS markers in pancreatic tissue was significantly reduced in the DCHD group compared with CP mice (P<0.05). In vitro, serum containing DCHD enhanced the mRNA level of Ptf1-α and Cpa1 which represent pancreatic exocrine function and inhibited ERS, Apoptosis, and PI3K/Akt signaling activation in 266-6 cells stimulated with caerulein. Furthermore, the expression of ERS marker including GRP78 and DDIT3 in acinar cells was significantly inhibited by PI3K inhibitors (LY294002) (P<0.05). After treatment of LY294002, the effect of DCHD-containing serum alleviating ERS of acinar cells was abrogated.

Conclusion: DCHD suppress ERS by regulating the PI3K/Akt pathway in pancreatic acinar cells and further alleviates pancreatic exocrine dysfunction. This study confirms the therapeutic potential of DCHD in pancreatic exocrine dysfunction, and offers a new therapeutic option for CP with pancreatic exocrine dysfunction.