4D-DIA-based proteomics analysis reveals the protective effects of Pidanjiangtang granules in IGT rat model.

Ethnopharmacological Relevance: The Pidanjiangtang (PDJT) formula was founded on the "Pidan" theory from the "Nei Jing." PDJT is considered to eliminate the accumulation of pathological products, remove heat sources, and prevent damage to organs such as the liver and islets. It is widely used in clinical practice to treat impaired glucose tolerance (IGT). However, the bioactive ingredients and underlying mechanisms are still unclear and need further investigation.

Objective: This study aimed to determine the therapeutic effect of PDJT on IGT rats and explore the mechanism of PDJT intervention on IGT by four-dimensional independent data acquisition (4D-DIA) proteomics analysis.

Materials And Methods: The IGT model was established by a high-fat diet combined with Streptozotocin (STZ) injection. The IGT rats were treated with low, medium, and high doses of PDJT orally for 42 days and compared with the Metformin positive control group. The therapeutic effects of PDJT on IGT rats were evaluated using the oral glucose tolerance test (OGTT), serum lipoprotein detection, insulin detection, liver histopathology, and hepatic steatosis assessment. 4D-DIA proteomics analysis was used to explore the differential proteins (DEPs) and potential pathways of PDJT. Finally, Western blotting and ELISA techniques were used to verify DEPs and major targets.

Results: PDJT can enhance glucose metabolism, restore islet β cell function, regulate lipoprotein metabolism, reduce hepatic steatosis, and consequently slow down the progression of IGT. In the proteomic analysis, a total of 355 DEPs were identified, and critical proteins were validated. The results indicated that the JAK2/STAT1 signaling pathway plays a pivotal role in the effects of PDJT. IκB-ζ may be a potential target for PDJT in regulating the inflammatory response of IGT.

Conclusion: PDJT is an effective formula for improving IGT, with its potential mechanism linked to the JAK2/STAT1/IκB-ζ signaling pathway. This study offers a novel approach to investigating the mechanisms of TCM formula through proteomics and offers new insight into exploring TCM treatment for IGT.