Oligomeric proanthocyanidin

Proanthocyanidin (PA) has demonstrated promise as a dental biomodifier for maintaining dentin collagen integrity, yet there is limited evidence regarding its efficacy in dentin repair. The aim of this study was to investigate the effect of PA on dentin remineralization through the polymer induced liquid precursor (PILP) process, as well as to assess the mechanical properties of the restored dentin. Demineralized dentin was treated with a PA-contained remineralization medium, resulting in the formation of PA-amorphous calcium phosphate (ACP) nanoparticles via the PILP process. The kinetics and microstructure of remineralized dentin were examined through the use of Fourier transform infrared spectroscopy(FTIR), attenuated total reflectance-FTIR, scanning electron microscopy, transmission electron microscopy. The results showed that the application of PA facilitated the process of dentin remineralization, achieving completion within 48 h, demonstrating a notable reduction in time required. Following remineralization, the mechanical properties of the dentin exhibited an elastic modulus of 15.89 ± 1.70 GPa and a hardness of 0.47 ± 0.08 GPa, which were similar to those of natural dentin. These findings suggest that combining PA with the PILP process can promote dentin remineralization and improve its mechanical properties, offering a promising new approach for dentin repair in clinical practice.

Phenanthrene (PHE) is a typical polycyclic aromatic hydrocarbon compound that is ubiquitous in the environment and accumulates in aquatic products, thereby posing a risk to food safety. Oligomeric proanthocyanidins (OPC) is widely distributed powerful antioxidants with potent antioxidant and anti-inflammatory properties. This study aimed to evaluate the alleviating effects of dietary OPC on oxidative stress, inflammatory suppression, and tissue damage caused by PHE exposure in loach (Misgurnus anguillicaudatus). In the study, loach was continuously exposed to 2.36 mg/L PHE for 28 days, after which they were fed a basal diet supplemented with 0, 200, 400, or 800 mg/kg OPC. The results displayed that PHE exposure resulted in significantly increased levels of liver health parameters (AST, ALT, COR, LDH, and ADA) compared to the control group (P < 0.05). The PHE-exposed fish showed the lowest levels of antioxidant enzymes (CAT, SOD, GSH, GST, GSH-Px, and GR) and the greatest levels of oxidative stress parameters (ROS and MDA). PHE exposure resulted in down-regulation of nrf2, ho-1, gsh-px, gst, and nqo-1, and up-regulation of keap-1 gene expressions in loach (P < 0.05). Moreover, PHE-induced decreased the levels of immunity indicators (CRP, MPO, C3, C4, IgM, and LYS). An up-regulation of pro-inflammatory genes (nf-κb, il-1β, il-8, il-6, il-12, and tnf-α) and a down-regulation of anti-inflammatory gene il-10 were the consequences of the PHE exposure. In addition, tissues showed histopathological alterations including vacuolization (liver), displaced nuclei (liver), atrophy (gills), glomerular congestion (kidney), and inflammatory cell infiltration (spleen) caused by PHE. Notably, dietary supplementation of OPC augmented immuno-antioxidant parameters, including their key genes, reduced oxidative stress and immunosuppression, and ameliorated tissue damage compared to fish exposed to PHE. In summary, supplementation with 400 mg/kg OPC in the diets could effectively alleviate the oxidative damage and inflammatory response induced by PHE exposure in loach through the Nrf2/NF-κB signaling pathway and enhance the defense ability against toxic substances of loach.