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BackgroundUncontrolled intimal hyperplasia (IH) after autologous saphenous vein grafting triggers a high restenosis rate; however, its association with the activation of NADPH oxidase (NOX)-related pathways is unclear. Here, we investigated the effects and mechanism of oscillatory shear stress (OSS) on grafted vein IH.MethodsThirty male New Zealand rabbits were randomly divided into control, high-OSS (HOSS), and low-OSS (LOSS) groups, and the vein grafts were harvested after 4 weeks. Hematoxylin and eosin staining and Masson staining assays were used to observe morphological and structural changes. Immunohistochemical staining was used to detect α-SMA, PCNA, MMP-2, and MMP-9 expression. Immunofluorescence staining was used to observe reactive oxygen species (ROS) production in the tissues. Western blotting was used to determine the expression levels of pathway-related proteins (NOX1, NOX2, AKT, p-AKT, and BIRC5), PCNA, BCL-2, BAX, and caspase-3/cleaved caspase-3 in tissues.ResultsBlood flow velocity was lower in the LOSS group than in the HOSS group, while vessel diameter did not change significantly. Shear rate was elevated in both HOSS and LOSS groups but was higher in the HOSS group. Additionally, vessel diameter increased with time in the HOSS and LOSS groups, whereas flow velocity did not. Intimal hyperplasia was significantly lower in the LOSS group than in the HOSS group. IH was dominated by smooth muscle fibers in the grafted veins and collagen fibers in the media. OSS restriction significantly reduced the α-SMA, PCNA, MMP-2, and MMP-9 levels. Moreover, ROS production and the expression of NOX1, NOX2, p-AKT, BIRC5, PCNA, BCL-2, BAX, and cleaved caspase-3 were phase-reduced in LOSS compared to the levels in the HOSS group. Total AKT was not differentially expressed among the three groups.ConclusionOSS promotes the proliferation, migration, and survival of subendothelial vascular smooth muscle cells in grafted veins, which may be related to the regulation of downstream p-AKT/BIRC5 levels through the increased production of ROS by NOX. Drugs inhibiting this pathway might be used to prolong vein graft survival time.

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Objective: Previous basic studies on the use of titanized polypropylene meshes in abdominal external hernia repair are not only limited, but also highly controversial. This study aims to investigate the modification effect of titanium compounds on polypropylene materials and compare the performance of two kinds of meshes both in vivo and in vitro.Methods: Human peritoneal mesothelial cells (HMrSV5), human epidermal fibroblasts (HSF), and human monocytic cells (THP-1) were cultured in vitro to simulate the abdominal external hernia environment. Titanized polypropylene meshes (Ti) and polypropylene mesh (Non-Ti) were co-cultured with the cells respectively. The effects of titanium compounds on cell growth were determined by cell activity and apoptosis, and the growth of cells on the mesh surface was assessed using a scanning electron microscope and a confocal microscope. In vivo experiments, different sizes titanized polypropylene meshes and polypropylene meshes were placed between the external oblique abdominal muscle and the internal oblique abdominal muscle, the parietal peritoneum, the serous layer of the descending colon, and the underside of the femoral nerve in rabbits. The effects of titanium compounds were evaluated by observing the anti-adhesion, anti-contraction, anti-fibrotic properties, and effects on nerves of the mesh.Results: Titanium compounds effectively reduced the effects of polypropylene material on cell growth, and improved the fixation and adhesion of HMrSV5, HSF and THP-1 (M0) on the surface of titanized polypropylene meshes. Furthermore, titanium compounds improved the adhesion, contraction and fibrosis of polypropylene material, as well as reduced nerve damage. This improvement demonstrated a regular trend with the type of titanized polypropylene meshes.Conclusion: The titanium compounds improved the biocompatibility of the polypropylene material, which was conducive to the fixation and adhesion of cells on the surface of the meshes, and alleviated the adhesion and contraction of the meshes, and the degree of tissue fibrosis, as well as the influence on nerves.