Peptide pool instability of precancerous lesions in rats with chronic pancreatitis model and/or without type 1 diabetes mellitus

The search for early and minimally invasive diagnostic approaches to pancreatic cancer (PC) remains an important issue. One of the most promising directions is to find a sensitive key in the metabolic changes during widespread causes of PC, i.e., chronic pancreatitis (CP) and diabetes mellitus (DM). The main objective of this study was to analyze the peptide pools in the blood plasma and pancreas of rats with modeling of CP and/or without type 1 DM in association with pancreas histopathological grading features. The study was conducted on white non-linear male rats, divided into 3 groups: 1st group: control, 2nd group: rats with cerulein-stimulated CP, and 3rd group: rats with CP and streptozotocin-inducible type 1 DM. Total protein and peptide content were determined in the pancreas and blood plasma. The peptide pools were fractionated using size-exclusion chromatography. Rats with CP showed a high degree of fibrosis in the pancreas and grade 1 ductal pancreatic intraepithelial neoplasia (PanIN), associated with decreased total peptides in the pancreas. In rats with CP and DM, 2nd and 3rd grade PanIN with pronounced acinar metaplasia was observed in association with decreasing total pancreatic protein and peptide pools. While there was a decrease in total protein and an increase in total peptide in blood serum, the changes were more pronounced in rats with CP and DM. A study revealed both qualitative and quantitative differences in the distribution of peptide pools in 2 groups with pathologies. Qualitatively, plasma samples from pathological groups exhibited an increased number of peaks. Quantitatively, there was a higher proportion of peptides with molecular weights exceeding 700 Da observed in both plasma and pancreas. The analysis of peptide pools obtained from plasma and PanIN development demonstrated that the peptide pool can serve as an early and complementary indicator of PC emergence.