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Objective:To evaluate the effect of rapamycin on the activity of NOD-like receptor C4 (NLRC4) inflammasomes in the rats with ventilator-induced lung injury (VILI).Methods:Thirty-six healthy clean-grade male Sprague-Dawley rats, aged 6-8 weeks, weighing 200-250 g, were divided into 3 groups ( n=12 each) using a random number table method: control group (group C), VILI group and rapamycin group (group RAPA). In group RAPA, rapamycin 4 mg·kg -1·d -1 was intraperitoneally injected once a day for 3 consecutive days before establishing the model, while the equal volume of normal saline was given instead in group C and group VILI.The patients were mechanically ventilated for 4 h (tidal volume 20 ml/kg, respiratory rate 80 breaths/min, inspiratory/expiratory ratio 1∶1, fraction of inspired oxygen 21%) in VILI and RAPA groups.Blood samples were collected from the femoral artery after the end of ventilation for blood gas analysis and for determination of serum interleukin-1β (IL-1β) and interleukin-18 (IL-18) concentrations (by enzyme-linked immunosorbent assay), and PaO 2 was recorded.The bronchoalveolar lavage fluid (BALF) was collected for determination of the neutrophil count and IL-1β and IL-18 concentrations by enzyme-linked immunosorbent assay.The lung tissues were obtained for examination of the pathological changes (under the light microscope) after HE staining which were scored and for determination of wet to dry weight (W/D) ratio, and expression of mammalian target of rapamycin (mTOR), NLRC4 and caspase-1 (by Western blot) and expression of NLRC4 mRNA (by real-time polymerase chain reaction). Results:Compared with group C, the W/D ratio, lung injury score, neutrophil counts in BALF, and concentrations of IL-1β and IL-18 in serum and BALF were significantly increased, PaO 2 was decreased, and the expression of mTOR, NLRC4, caspase-1 and NLRC4 mRNA was up-regulated in group VILI and group RAPA ( P<0.01). Compared with group VILI, the W/D ratio, lung injury score, neutrophil counts in BALF, and concentrations of IL-1β and IL-18 in serum and BALF were significantly decreased, PaO 2 was increased, and the expression of mTOR, NLRC4, caspase-1 and NLRC4 mRNA was down-regulated in group RAPA ( P<0.05). Conclusion:The mechanism by which rapamycin alleviates VILI may be related to inhibiting activation of mTOR signaling pathway and inhibiting the activity of NLRC4 inflammasomes in rats.
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Objective:To evaluate the relationship between protein kinase C-delta (PKCδ) and pyroptosis during ventilator-induced lung injury (VILI) in rats.Methods:Thirty-six clean-grade healthy adult male Sprague-Dawley rats, weighing 200-250 g, were divided into 3 groups ( n=12 each) using a random number table method: control group (group C), group VILI, and VILI plus specific PKCδ inhibitor KAI 9803 group (group K). Phosphate buffer solution 200 μl was injected through the tracheal tube after intubation in group VILI, and KAI 9803 200 μg/kg was given instead in group K. The patients were mechanically ventilated (tidal volume 40 ml/kg, respiratory rate 60 breaths/min, inspiratory/expiratory ratio 1∶2, fraction of inspired oxygen 21%, positive end-expiratory pressure 0) for 4 h. Blood samples were taken from the femoral artery at the end of mechanical ventilation for blood gas analysis, and PaO 2 was recorded.Animals were sacrificed at the end of ventilation, lung tissues were removed, and bronchoalveolar lavage fluid (BALF) was prepared.The total protein concentrations in BALF were measured by coomassie blue staining, and concentrations of interleukin-18 (IL-18) and IL-1β in BALF by enzyme-linked immunosorbent assay.Lung tissues were obtained for microscopic examination of the pathological changes which were scored and for determination of wet/dry weight ratio (W/D ratio) and expression of PKCδ and gasdermin D N terminal fragment (GSDMD-N) protein and mRNA (by Western blot or by quantitative real-time polymerase chain reaction). Results:Compared with group C, the lung injury score, W/D ratio, and concentrations of total protein, IL-18 and IL-1β in BALF were significantly increased, PaO 2 was decreased, and the expression of PKCδ and GSDMD-N protein and mRNA was up-regulated in VILI and K groups ( P<0.01). Compared with group VILI, the lung injury score, W/D ratio, and concentrations of total protein, IL-18 and IL-1β in BALF were significantly decreased, PaO 2 was increased, and the expression of PKCδ and GSDMD-N protein and mRNA was down-regulated in group K ( P<0.05 or 0.01). Conclusion:PKCδ can mediates the pathophysiological process of VILI in which pyrolysis is involved in rats.
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Objective To evaluate the role of mitochondrial fission in anoxia-reoxygenation injury to rat hippocampal neurons.Methods Neurons were enzymatically isolated from hippocampi of newborn Sprague-Dawley rats (less than 24 h old).The primary hippocampal neurons were cultured and seeded in 25 mm × 25 mm culture flasks at a density of 7 × 105/ml.The cultured neurons were randomly assigned into 3 groups (n =18 each) using a random number table:control group (C group),anoxia-reoxygenation group (I/R group),and mitochondrial fission inhibitor mdivi-1 group (M group).In group I/R,the vehicle dimethyl sulfoxide (DMSO,final concentration ＜ 0.1％) was added prior to anoxia and the cells were then incubated for 40 min.In group M,mdivi-1 (dissolved in DMSO,final concentration of DMSO ＜ 0.1％) was added prior to anoxia and the cells were then incubated for 40 min.The hippocampal neurons were subjected to oxygen-glucose deprivation (OGD) for 6 h followed by restoration of O2 supply for 20 h.After 20 h of reoxygenation,the level of reactive oxygen species (ROS) (by ELISA),cell apoptosis (using flow cytometry),and expression of mitochondrial fission protein Drp1,Bcl-2 and Bax (by Western blot) were measured.The apoptosis rate and the ratio of Bcl-2 to Bax were calculated.Results Compared with C group,ROS content and apoptosis rate were significantly increased,the expression of Drp1 and Bax was up-regulated,the expression of Bcl-2 was down-regulated,and the ratio of Bcl-2 to Bax was decreased in I/R group (P ＜ 0.05).Compared with I/R group,ROS content and apoptosis rate were significantly decreased,the expression of Drp1 and Bax was down-regulated,the expression of Bcl-2 was up-regulated,and the ratio of Bcl-2 to Bax was increased in M group (P ＜ 0.05).Conclusion Mitochondrial fission is involved in anoxia-reoxygenation injury to rat hippocampal neurons via mitochondria-mediated apoptotic pathway.
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BACKGROUND:Autologous shed blood washing with the autologous transfusion system involving recovery, anticoagulation, centrifugation, concentrating and washing has been widely used in clinical practice. OBJECTIVE:To clarify the characteristics of erythrocytes washing with autologous transfusion system, including recovery rate and hematocrit, the changes of shape, deformability, flow properties and in vivo half-life, oxygen carrying and delivering capacity and erythrocyte immunity and immunereceptor expression. METHODS:The literatures published from January 1987 to January 2013 were retrieved by the first author in Wanfang and PubMed databases. Key words were“blood transfusion, autologus, blood preservation, erythrocytes”in English and Chinese. A total of 200 literatures relating to the erythrocyte characteristics in autologous blood transfusion were found by the computer, 60 of which were retained for further analysis after eliminating repetitive researches. RESULTS AND CONCLUSION:Because of the mechanical force, such as negative pressure suction, centrifugal separation, and inflammatory mediators, enzymes, activated complements released by various damaged tissues and cells, the col ected erythrocytes were damaged to some extent. As a result, the total recovery rate of erythrocytes depended on the recovery rate, storage breakage rate and cleaning loss rate. The oxygen carrying capacity of erythrocytes was not influenced significantly by this procedure, so the recycled erythrocytes had the same oxygen carrying capacity with normal erythrocytes. To some extent, the number of surface receptors and immune function of recycled erythrocytes descended, but they were better than the erythrocytes preserved for 2 weeks. Studies suggested that blood recovery technology should be improved to reduce the functional decline in immune adherence of the recycled erythrocytes.