ABSTRACT
To observe the efficacy of compound Dendrobium on Sprague Dawley rats (SD) hypertension model induced by "dietary disorders" and its relevant mechanism, totally 50 SD rats were fed with high-sugar, high-fat diet and alcohol for four weeks. According to the blood pressure after modeling, the rats were divided into model group, valsartan group (8 mg·kg⁻¹), low, medium and high-dose Dendrobium candidum compound groups (1.65, 3.30, 5.00 g·kg⁻¹), with 10 rats in each group, and the other 10 SD rats were also taken as the normal group. After four weeks of treatment, blood pressure was measured. Orbital blood was collected for the determination of serum cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol (HDL), calculation of atherosclerosis index (AI). Nitric acid reductase method was used to detect serum nitric oxide (NO); the levels of serum endothelin-1 (ET-1) and intercellular adhesion molecule-1 (ICAM-1) were measured by ELISA. The rats were put to death after the last administration, and the protein expressions of PI3K/AKT/eNOS in thoracic aorta of rats in each group were detected by Western blot. The aorta was separated and stained with hematoxylin-eosin (HE) to observe the changes in the endothelium and blood vessels in the thoracic aorta. Masson staining was used to observe the formation of aortic collagen. The expressions of nitric oxide synthase (eNOS) and ICAM-1 in aortic endothelial cells were observed by immunohistochemistry. In contrast, the results show D. candidum compound can significantly reduce the blood pressure in hypertensive rats, increase HDL-c, and reduce AI, while increasing serum NO content, decreasing ET-1 and ICAM-1 levels and promoting PI3K/AKT/NOS protein expressions. The lesion degree of the D. candidum compound group was reduced, and the collagen deposition was significantly reduced. Meanwhile, D. candidum compound can significantly increase the expression of eNOS, and reduce the formation of ICAM-1.Therefore, D. candidum compound has an obvious antihypertensive effect on hypertensive rats, which may be related to the increase in PI3K/AKT/eNOS signaling pathways and NO generation, the inhibition of the secretion of ICAM-1 and ET-1, the protection of the vascular endothelium and the improvement of aortic disease.
ABSTRACT
<p><b>OBJECTIVE</b>To evaluate the thickness and viscoelasticity of whole saliva (WS), parotid saliva (PS) and submandibular/sublingual gland saliva (SMSLS) film adsorption on the hydroxyapatite (HA) surface.</p><p><b>METHODS</b>Ultra-thin layer of HA nanocrystals was coated on the dissipation TiO(2) sensor of gold quartz crystal microbalance using electrophoretic deposition technique. The thickness of the HA layer was measured by the ellipsometer, and element analysis was conducted using X-ray photoelectron spectroscopy. Atomic force microscopy and scanning electron microscope were used to observe its morphology. The in-situ adsorption thickness, the shear elastic modulus and the shear viscosity of salivary layers (WS, PS and SMSLS) on HA surfaces were investigated. The statistical data were analysed by an one-way ANOVA analysis followed by a SNK-q test.</p><p><b>RESULTS</b>The results show that the HA layer was a plate-like morphology with 1.53 ± 0.12 in Ca/P molar ratio, (19.1 ± 0.9) nm in the thickness and (6.5 ± 1.6) nm in the roughness. The thickness of salivary film was SMSLS [(21.84 ± 1.25) nm] > WS[(17.91 ± 1.35) nm] > PS [(14.30 ± 1.03 nm) (P < 0.05). The shear elastic modulus of salivary film was PS [(0.61 ± 0.01) MPa] > SMSLS [(0.31 ± 0.09) MPa] and WS [(0.25 ± 0.03) MPa] (P < 0.05). The trend of the shear viscosity was opposite to one of thickness.</p><p><b>CONCLUSIONS</b>The characteristics of saliva adsorption on HA surface suggest that the thicker, softer and more hydrated properties for the SMSLS and WS films are likely to afford a stronger lubrication to protect oral surfaces from wear and dehydration. The viscoelasticity of the PS film is probably related to the retention covering the oral cavity.</p>