ABSTRACT
Objective@#To evaluate the effect of dexmedetomidine on pyroptosis during lung ischemia-reperfusion (I/R) in rats.@*Methods@#Adult male Sprague-Dawley rats, weighing 250-320 g, were used in this study.The model of isolated lung perfusion was established using an IL-2 Isolated Perfused Rat or Guinea Pig Lung System after the rats were anesthetized.Thirty lungs in which an ex vivo lung perfusion model was successfully established were divided into 3 groups (n=10 each) by a random number table method: control group (C group), I/R group and dexmedetomidine group (DEX group). The lungs were continuously perfused with K-H solution for 150 min in C group.After 15 min of perfusion, lungs were subjected to 60-min suspension of ventilation and perfusion, followed by 75 min of reperfusion and ventilation to establish the model of lung I/R injury in I/R and DEX groups.In DEX group, dexmedetomidine 10 nmol/L was added to K-H solution at the beginning of reperfusion.Lung tissues were obtained for determination of wet/dry weight ratio (W/D ratio) and for examination of pathological changes (with a light microscope) and ultrastructure (using an electron microscope), and the alveolar damage rate (IAR) was calculated.The expression of pyroptosis-related factors including NOD-like receptor family protein 3 (NLRP3), caspase-1, interleukin-1β (IL-1β), IL-18 and gasdermin D (GSDMD) protein and mRNA was detected by Western blot or by real-time polymerase chain reaction.@*Results@#Compared with C group, the W/D ratio and IAR in lung tissues were significantly increased, and the expression of NLRP3, caspase-1, IL-1β, IL-18 and GSDMD protein and mRNA was up-regulated in I/R and DEX groups (P<0.05). Compared with I/R group, the W/D ratio and IAR in lung tissues were significantly decreased, the expression of NLRP3, caspase-1, IL-1β, IL-18 and GSDMD protein and mRNA was down-regulated (P<0.05), and the pathological changes were significantly attenuated in DEX group.@*Conclusion@#The mechanism by which dexmedetomidine reduces isolated rat lung I/R injury may be related to inhibiting pyroptosis.
ABSTRACT
Objective To evaluate the effect of dexmedetomidine on pyroptosis during lung ischemia-reperfusion (I/R) in rats.Methods Adult male Sprague-Dawley rats,weighing 250-320 g,were used in this study.The model of isolated lung perfusion was established using an IL-2 Isolated Perfused Rat or Guinea Pig Lung System after the rats were anesthetized.Thirty lungs in which an ex vivo lung perfusion model was successfully established were divided into 3 groups (n=10 each) by a random number table method:control group (C group),I/R group and dexmedetomidine group (DEX group).The lungs were continuously perfused with K-H solution for 150 min in C group.After 15 min of perfusion,lungs were subjected to 60-min suspension of ventilation and perfusion,followed by 75 min of reperfusion and ventilation to establish the model of lung I/R injury in I/R and DEX groups.In DEX group,dexmedetomidine 10 nmol/L was added to K-H solution at the beginning of reperfusion.Lung tissues were obtained for determina-tion of wet/dry weight ratio (W/D ratio) and for examination of pathological changes (with a light microscope) and ultrastructure (using an electron microscope),and the alveolar damage rate (IAR) was calculated.The expression of pyroptosis-related factors including NOD-like receptor family protein 3 (NLRP3),caspase-1,interleukin-1β (IL-1β),IL-18 and gasdermin D (GSDMD) protein and mRNA was detected by Western blot or by real-time polymerase chain reaction.Results Compared with C group,the W/D ratio and IAR in lung tissues were significantly increased,and the expression of NLRP3,caspase-1,IL-1β,IL-18 and GSDMD protein and mRNA was up-regulated in I/R and DEX groups (P＜0.05).Compared with I/R group,the W/D ratio and IAR in lung tissues were significantly decreased,the expression of NLRP3,caspase-1,IL-1β,IL-18 and GSDMD protein and mRNA was down-regulated (P＜0.05),and the pathological changes were significantly attenuated in DEX group.Conclusion The mechanism by which dexmedetomidine reduces isolated rat lung I/R injury may be related to inhibiting pyroptosis.
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Objective To evaluate the effect of sevoflurane on unfolded protein response-related cell apoptosis during acute lung injury in rats undergoing cardiopulmonary bypass ( CPB) . Methods For-ty-eight clean-grade healthy adult male Sprague-Dawley rats, aged 6-8 weeks, weighing 250-300 g, were allocated into 3 groups ( n=16 each) using a random number table method: sham operation group ( Sham group) , CPB group and sevoflurane group ( Sev group) . Left common carotid artery and right internal jugu-lar vein were only cannulated in group Sham. After establishing CPB, the flow rate was gradually adjusted to the maximum (100 ml·kg-1·min-1) and maintained for 60 min in group CPB. Two percent sevoflurane was inhaled for 30 min, and 15 min later the model of CPB was established in Sev group. Rats were sacri-ficed at 1 h after the end of CPB, lungs were removed and lung tissues were obtained. The pathological changes and ultrastructure of lung tissues were examined with a light microscope and with an electron micro-scope, respectively. The wet to dry weight ratio ( W∕D ratio) , apoptosis in lung cells ( by TUNEL assay) , expression of glucose-regulated protein 78 ( GRP78) , CCAAT∕enhancer-binding protein homologous protein (CHOP), c-Jun N-terminal kinase (JNK) and caspase-12 mRNA was determined by real-time polymerase chain reaction. The expression of GRP78, CHOP, phosphorylated JNK (p-JNK) and caspase-12 was de-tected by Western blot. The index of quantitative assessment of histologic lung injury ( IQA) was measured, and apoptotic index ( AI) was calculated. Results Compared with Sham group, the W∕D ratio, IQA and AI were significantly increased, the expression of GRP78, CHOP, JNK and caspase-12 was up-regulated ( P<0. 05) , and the pathological changes of lung tissues were accentuated in CPB group. Compared with CPB group, the W∕D ratio, IQA and AI were significantly decreased, the expression of GRP78, CHOP, JNK and caspase-12 was down-regulated ( P<0. 05) , and the pathological changes of lung tissues were sig-nificantly attenuated in Sev group. Conclusion The mechanism by which sevoflurane mitigates acute lung injury induced by CPB is related to inhibiting unfolded protein response related cell apoptosis in lung tissues of rats.
ABSTRACT
Objective To evaluate the effects of dexmedetomidine (DEX) on cell apoptosis induced by endoplasmic reticulum stress and c-Jun N-terminal kinase (JNK) pathway during one-lung ventilation (OLV) in rats.Methods Sixty male Sprague-Dawley rats were randomly allocated into 6 groups (n =10 each):sham operation group (Sham group),OLV group,OLV + atipamezole (α2 receptor antagonist) group (AD group),OLV + atipamezole + DEX group (DEX+AD group),OLV + low-dose DEX group (DEX-L group) and OLV + high-dose DEX group (DEX-H group).The animals were anesthetized with 10％ chloral hydrate 4.5 ml/kg,tracheostomized and mechanically ventilated.Bilateral lungs were ventilated for 2.5 h in Sham group.The right lung was ventilated for 2.0 h followed by 0.5 h two-lung ventilation in OLV group.In DEX-L and DEX-H groups,DEX was infused intravenously for 1 h at a rate of 2.5 μg · kg-1 · h-1 and 5.0 μg · kg-1 · h-1,respectively,starting from 1 h prior to OLV.Atipamezole 250 μg/kg was injected intravenously at 1 h prior to OLV in AD group.Atipamezole 250 μg/kg was injected intravenously at the onset of DEX infusion (5.0 μg · kg-1 · h-1) in DEX+AD group.The rats were sacrificed and left lungs were removed for determination of weight to dry lung weight ratio (W/D),cell apoptosis in lung tissues (by TUNEL),and expression of glucose-regulated protein 78 (GRP78) mRNA and protein,JNK mRNA and phosphorylated JNK (p-JNK) protein (by RT-PCR and Western blot).Pathological changes of lungs were examined and the injured alveolus rate (IAR) was counted under light microscope.The changes in ultrastructure of lung tissues were observed under transmission electron microscope.Apoptosis index (AI) was calculated.Results W/D,AI and IAR were significantly higher in OLV,AD and DEX+AD group than in Sham group,while lower in DEX-L and DEX-H groups than in OLV,AD and DEX+AD groups.The pathological changes of the structure of lung tissues were observed in OLV,AD and DEX+AD groups,while the pathological changes were significantly alleviated in DEX-L and DEX-H groups.In OLV,AD and DEX + AD groups,there was apoptosis in lots of pulmonary vascular endothelial cells and alveolar epithelial cells,while cell apoptosis was significantly reduced after administration of DEX.The expression of GRP78 mRNA and protein,JNK mRNA and p-JNK protein was significantly higher in OLV,AD and DEX+AD groups than in Sham group,and lower in DEX-L and DEX-H groups than in OLV,AD and DEX +AD groups.Conclusion DEX pretreatment can protect lungs during OLV,and inhibited JNK signaling pathway and reduced cell apoptosis induced by endoplasmic reticulum stress may be involved in the mechanism.