Compound Danshen injection improves endotoxin-induced microcirculatory disturbance in rat mesentery

AIM: To investigate the effect of compound Danshen injection on lipopolysaccharide (LPS)-induced rat mesenteric microcirculatory dysfunctions and the underlying possible mechanism by an inverted intravital microscope and high-speed video camera system. METHODS: LPS was continuously infused through the jugular artery of male Wistar rats at the dose of 2 mg/kg per hour. Changes in mesenteric microcirculation,such as diameters of arterioles and venules,velocity of RBCs in venules,leukocyte rolling,adhesion and emigration,free radicals released from post-capillary venules,FITC- albumin leakage and mast cell degranulation,were observed through an inverted intravital microscope assisted with CCD camera and SIT camera. Meanwhile,the expression of adhesion molecules CD11b/CD18 and the production of free radical in neutrophils,and the expression of intercellular adhesion molecule 1 (ICAM-1) in human umbilical vein endothelial cells (HUVECs) were quantified by flow cytometry (FACS) in vitro. RESULTS: The continuous infusion with LPS resulted in a number of responses in microcirculation,including a significant increase in the positive region of venulestained with Monastral blue B,rolling and adhesion of leukocytes,production of oxygen radical in venular wall,albumin efflux and enhanced mast cell degranulation in vivo,all of which,except for the leukocyte rolling,were attenuated by the treatment with compound Danshen injection. Experiments performed in vitro further revealed that the expression of CD11b/CD18 and the production of oxygen free radical in neutrophils,and the expression of ICAM-1 in HUVECs were increased by exposure to LPS,and they were attenuated by compound Danshen injection. CONCLUSION: These results suggest that compound Danshen injection is an efficient drug with multi-targeting potential for improving the microcirculatory disturbance.

Mechanical and fatigue properties of self-piercing riveted joints in high-strength steel and aluminium alloy

Static tensile and fatigue tests were performed on shear and tensile self-piercing riveted aluminium-steel structures to evaluate their mechanical and fatigue properties. The influences of the thickness and the strength of the high strength steel on mechanical and fatigue performances were investigated based on the tensile and F-N curves of the joints. The results show that mechanical and fatigue properties of the shear self-piercing riveted joints are much better than those of the tensile self-piercing riveted joints. Mechanical and fatigue performances of the two joints were significantly influenced by the thickness and strength of the steel sheet, and were markedly improved when the thickness of steel sheet increased. The steel strength showed significantly different effects on shear and tensile riveted structures, i. e. , when the steel strength increased, the strength of the shear structure greatly increased while the tensile structure just had a slight increase in the strength. Fatigue failure generally occurred in the sheet materials and the fatigue crack location changed with increasing the sheet thickness and the sheet strength.