Objective To analyze the effect of short hairpin RNA (shRNA) silencing Salusin-β on endothelial dysfunction in diabetes mellitus (DM) rats and its potential mechanism. Methods Twelve of 52 SD rats were randomly selected as the normal control group (NC group). The rest of rats were fed high sugar and high fat diet and intraperitoneally injected streptozotocin 60 mg/kg to prepare DM model. Thirty-six rats were successfully modeled and were divided into the DM group, the Ad-Scr shRNA group and the Ad-Salusin-β shRNA group, with 12 rats in each group. Adenovirus empty vector encoding scramble shRNA (Ad-scramble shRNA) was injected into the tail vein of rats in the Ad-Scr shRNA group, and adenoviral vector encoding Salusin-β shRNA (Ad-Salusin-β shRNA) was injected into the tail vein of rats in the Ad-Salusin-β shRNA group. The drug was administered once every 2 weeks. The NC group and the DM group were injected with the same volume of normal saline. After 4 weeks, fasting blood glucose (FBG) and serum Salusin-β levels and the vasodilation function of thoracic aorta were measured. Enzyme linked immunosorbent assay was used to detect levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-6, IL-1β, malondialdehyde (MDA) and superoxide dismutase (SOD) in thoracic aorta. Dihydroethidium (DHE) staining was used to detect the level of reactive oxygen species (ROS) in the thoracic aorta. Hematoxylin-eosin staining was used to observe histopathological changes of thoracic aorta. Fluorescence quantitative PCR was used to detect mRNA levels of Salusin-β and nicotinamide adenine dinucleotide phosphate oxidase 2 (NOX2) in thoracic aorta. Western blot assay was used to detect expression levels of NOX2 and nuclear factor-κB p65 (NF-κB p65) protein in thoracic aorta. Results Compared with the NC group, the FBG and serum Salusin-β were increased, TNF-α, IL-6, IL-1β, MDA and ROS in thoracic aorta were also increased, and intima-media thickness of the thoracic aorta was thickened in the DM group. Salusin-β mRNA, NOX2 mRNA and protein, nuclear NF-κB p65 protein levels were increased in the DM group. Ach induced endothelium dependent vasodilation, thoracic aorta SOD, cytoplasmic NF-κB p65 protein levels were decreased (P<0.05). Compared with the DM group and the Ad-Scr shRNA group, FBG and serum Salusin-β decreased, thoracic aorta TNF-α, IL-6, IL-1β, MDA and ROS decreased, intima-media thickness of thoracic aorta became thinner in the Ad-Salusin-β shRNA group. Salusin-β mRNA, NOX2 mRNA and protein, nuclear NF-κB p65 protein levels were decreased in the Ad-Salusin-β shRNA group, and Ach induced endothelium dependent vasodilation, thoracic aorta SOD, cytoplasmic NF-κB p65 protein levels were increased (P<0.05). Conclusion shRNA silencing Salusin-β can reduce endothelial dysfunction in DM rats, and its mechanism may be related to the inhibition of the activation of NOX2/ROS/NF-κB signaling pathway.
