Identification of novel peptides from goat milk casein that ameliorate high-glucose-induced insulin resistance in HepG2 cells.

In this study, we investigated the effect of goat milk casein hydrolysates on glucose consumption rate, intracellular glycogen concentration, and mRNA expression of gluconeogenesis-related genes, including phosphoenolpyruvate carboxykinase 1 (PCK1) and glucose-6-phosphatase catalytic subunit (G6PC), in insulin-resistant HepG2 cells. From the obtained hydrolysates, we also purified and characterized novel peptides that ameliorated high-glucose-induced insulin resistance in HepG2 cells. The 3-h hydrolysate caused the highest glucose consumption rate in insulin-resistant HepG2 cells. It also showed positive effects on promoting intracellular glycogenesis and reducing mRNA expression of PCK1 and G6PC. We separated the obtained hydrolysates into 3 fractions (F1, F2, and F3) by gel filtration chromatography; we further purified F1 using reversed-phase HPLC and identified peptides using liquid chromatography-tandem mass spectrometry. The bioactive peptides identified were SDIPNPIGSE (αS1-casein, f195-204), NPWDQVKR (αS2-casein, f123-130), SLSSSEESITH (ß-casein, f30-40), and QEPVLGPVRGPFP (ß-casein, f207-219). Our findings indicated that specific bioactive peptides from goat milk casein hydrolysates ameliorated insulin resistance in HepG2 cells that had been treated with high glucose. This is a first step toward determining whether goat milk casein hydrolysates can be used as food ingredients to ameliorate insulin resistance.

[Evaluating the level of occupational stress and its influence factors among traffic police in a district in Shanghai].

Objective: To investigate the high occupational stress and its influencing factors in traffic police in Shanghai. Methods: 728 traffic police were selected as the study subjects, and the《Occupational Health Questionnaire》was used to investigate and evaluate their job demand-control (JDC) and effort-reward imbalance model (ERI) occupational stress situation respectively. The related influencing factors were analyzed. Results: The prevalence rates of high occupational stress in JDC and ERI models were 74.6% (543/728) and 51.5% (375/728) . The influencing factors of JDC were education, marriage, average weekly hours (χ(2)=16.82, 10.04, 18.71, P<0.05) , and The influencing factors of ERI were gender, age, marriage, real monthly income level, education, work experience, and average weekly hours (χ(2)=7.02, 26.18, 6.73, 50.42, 4.75, 26.61, 112.98, 6.19, P<0.05) . The JDC multivariate logistic analysis indicated that the risk of occupational stress of married police was 2.81 times as high as that of Unmarried ones. The risk of occupational stress of traffic police with more education was 1.92 times as high as that of low eduacation, average weekly working 41-50 hours and≥51 hours was 2.53, 3.12 times as high as that of ones with average working 40 hours, respectivly. Meanwhile, the ERI multivariate logistic analysis indicated that high income level is the protective factor of occupational stress. The traffic police with 15-<20 working years were more likely to occur higher occupational stress. The traffic police with the more average weekly hours had greater possibility of higher occupational stress. Conclusion: The main influencing factors of JDC and ERI are marriage, real monthly income level, education, work experience, and average weekly hours.