RESUMO
For blood pumps with a rotating vane-structure, hemolysis values are estimated using a stress-based power-law model. It has been reported that this method does not consider the red blood cell (RBC) membrane's shear resistance, leading to inaccurate estimation of the hemolysis value. The focus of this study was to propose a novel hemolysis model which can more accurately predict the hemolysis value when designing the axial flow blood pump. The movement behavior of a single RBC in the shear flow field was simulated at the mesoscale. The critical value of shear stress for physiological injury of RBCs was determined. According to the critical value, the equivalent treatment of RBC aging was studied. A novel hemolysis model was established considering the RBC's aging and the hemolysis' initial value. The model's validity was verified under the experimental conditions of shear stress loading and the conditions of the shear flow field of the blood pump. The results showed that compared with other hemolysis models for estimating the hemolysis value of blood pumps, the novel hemolysis model proposed in this paper could effectively reduce the estimation error of the hemolysis value and provide a reference for the optimal design of rotary vane blood pumps.
RESUMO
Blood pump design efforts are focused on enhancing hydraulic effectiveness and minimizing shear stress. Unlike conventional blood pumps, interventional microaxial blood pumps have a unique outflow structure due to minimally invasive technology. The outflow structure, composed of the diffuser and cage bridges, is crucial in minimizing the pump size to provide adequate hemodynamic support. This study proposed four outflow structures of an interventional microaxial blood pump depending on whether the diffuser with or without blades and cage bridges were straight or curved. The outflow flow structure's effect on the blood pump's hydraulic performance and shear stress distribution was evaluated by computational fluid dynamics and hydraulic experiments. The results showed that all four outflow structures could achieve the pressure and flow requirements specified at the design point but with significant differences in shear stress distribution. Among them, the outflow structure with curved bridges would make the blood dispersed more evenly when flowing out of the pump, which could effectively reduce the shear stress at the cage bridges. The outflow structure with blades would aggravate the secondary flow at the leading edge of the impeller, increasing the risk of flow stagnation. The combination of curved bridges and the bladeless diffuser had a relatively better shear stress distribution, with the proportion of fluid exposed to low scalar shear stress (<50 Pa) and high scalar shear stress (>150 Pa) in the blood pump being 97.92% and 0.26%, respectively. It could be concluded that the outflow structure with curved bridges and bladeless diffuser exhibited relatively better shear stress distribution and a lower hemolysis index of 0.00648%, which could support continued research on optimizing the microaxial blood pumps.
RESUMO
Tiao He Yi Wei granule (DHYW), a traditional Chinese medicine, has been used for the treatment of gastric ulcer in clinical setting. The purpose of the present study was to investigate the possible effect of DHYW and explore the underlying mechanism against ethanol-induced gastric ulcer in mice. The model of ethanol-induced gastric ulcer in mice was induced by ethanol (0.2 mL/kg). Administration of DHYW at the doses of 250, 500 mg/kg body weight prior to the ethanol ingestion could effectively protect the stomach from ulceration. The gastric lesions were significantly ameliorated in the DHYW group compared with that in the model group. Treatment with DHYW markedly decreased the levels of interleukin-6 (IL-6), IL-1ß, and tumor necrosis factor-α (TNF-α). In addition, DHYW treatment elevated myeloperoxidase (MPO) level in stomach, increased superoxide dismutase (SOD) activity, and decreased malonaldehyde (MDA) content in serum and stomach compared with those in the model group. DHYW significantly inhibited NF-κB pathway expressions in the gastric mucosa ulcer group. Taken together, DHYW exerted a gastroprotective effect against gastric ulceration and the underlying mechanism might be associated with NF-κB pathway.
RESUMO
In the present study, we investigated anti-inflammatory effects of Sangxingtang (SXT) on acute lung injury using a lipopolysaccharide (LPS)-induced acute lung injury (ALI) mouse model. The cell counting in the bronchoalveolar lavage fluid (BALF) was performed. The degree of lung edema was evaluated by measuring the wet/dry weight (W/D) ratio. The superoxidase dismutase (SOD) and myeloperoxidase (MPO) activities were assayed by SOD and MPO kits, respectively. The levels of inflammatory mediators, including tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), were assayed by the enzyme-linked immunosorbent assay methods. Pathological changes of lung tissues were observed by Hematoxylin and eosin (HE) staining. The inflammatory signaling pathway-related proteins nuclear factor mitogen activated protein kinases (P38MAPK), extracellular regulated protein kinases (Erk), c-Jun N-terminal kinase (Jnk) and nuclear transcription factor (NF-κB) p65 expressions were measured by Western blotting. Our results showed that the treatment with the SXT markedly attenuated the inflammatory cell numbers in the BALF, decreased the levels of P-P38MAPK, P-Erk, P-Jnk and P-NF-κB p65 and the total protein levels in lungs, improved the SOD activity and inhibited the MPO activity. Histological studies demonstrated that SXT substantially reduced the LPS-induced neutrophils in lung tissues, compared with the untreated LPS group. In conclusion, our results indicated that SXT had protective effects on LPS-induced ALI in mice.