scholarly journals Dexmedetomidine Attenuates Lung Ischemia-reperfusion Injury in Rats by Reducing Mitochondrial Dysfunction

Author(s):  
Yan Zhang ◽  
Yao Lu ◽  
Kai Wang ◽  
Mei-yan Zhou ◽  
Cong-you Wu ◽  
...  

Abstract Background: Lung ischemia-reperfusion injury (LIRI) is a significant clinical problem occurring after lung transplantation. LIRI is mediated by the overproduction of reactive oxygen species (ROS) and inflammatory activation. Previous studies have confirmed that dexmedetomidine (DEX) exerts a protective effect on LIRI, which potentially causes severe mitochondrial dysfunction. However, the specific mechanisms remain unclear. Our study was to explore whether dexmedetomidine exerts a beneficial effect on LIRI by reducing mitochondrial dysfunction. Methods: Two different models were used in our study. For the in vivo experiment, thirty-two male Sprague-Dawley rats were randomly divided into Sham, ischemia-reperfusion (I/R), DEX+I/R and DEX+yohimbine+I/R (DY+I/R) groups. Similarly, pulmonary vascular endothelial cells (PVECs) from SD rats were divided into Control, oxygen glucose deprivation (OGD), D+OGD and DY+OGD groups.Results: In our experiment, we confirmed severe lung damage after LIRI that was characterized by significantly pulmonary histopathology injury, a decrease in the oxygenation index (PaO2/FiO2) and an increase in the wet-to-dry weight ratio, while DEX treatment mitigated this damage. In addition, the DEX pretreatment significantly attenuated I/R-induced oxidative stress by decreasing the level of ROS in the mitochondria in vitro. Moreover, the DEX treatment enhanced mitochondrial biogenesis and autophagy by increasing the expression of peroxisome proliferator-activated receptor-gamma coactivator-1α (PGC-1α), mitochondrial transcription factor A (Tfam), PTEN-induced putative kinase 1 (PINK1), Parkin and dynamin 1-like protein 1 (Drp1). Conclusions: These data suggest that DEX may alleviate LIRI by reducing mitochondrial dysfunction through the induction of mitochondrial biogenesis and autophagy.

2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Chandu Vemuri ◽  
Junjie Chen ◽  
Rohun U Palekar ◽  
John S Allen ◽  
Xiaoxia Yang ◽  
...  

Objective: Thrombin mediated microvascular thrombosis plays a crucial role in the pathogenesis of acute renal reperfusion injury following transient ischemia. We hypothesize that anti-thrombin nanoparticles will ameliorate acute renal injury by inhibiting microvascular thrombosis. Methods: Adult, male Sprague Dawley rats were randomized into two groups of 5 to receive tail vein injections of saline or nanoparticles loaded with Phe[D]-Pro-Arg-Chloromethylketone (NP-PPACK). Immediately following injection, all animals underwent operative bilateral renal artery occlusion to create 45 minutes of warm ischemia, followed by restoration of renal blood flow. Blood samples were drawn daily and animals were euthanized on day 1 or 7 for histologic analysis of kidney injury (H&E, TUNEL and thrombin staining). Results: Histologic analysis of renal tissue revealed significant apoptosis, necrosis and thrombin accumulation 1 day after ischemia-reperfusion, confirming acute kidney injury. The peak creatinine (mg/dl) on day 1 was significantly lower in NP-PPACK treated animals (0.57 +/- 0.07 (SEM)) than in saline treated controls (1.40 +/- 0.20 (SEM); p-value <0.01). Furthermore, animals treated with NP-PPACK continued to exhibit less renal dysfunction for 7 days after injury (Figure 1). Conclusion: Histologically confirmed intrarenal thrombosis was detected one day after ischemia-reperfusion injury. Targeted inhibition of thrombin with NP-PPACK prevented a decline in renal function following transient occlusion. Future work will focus on defining the underlying mechanisms of this effect.


2021 ◽  
Author(s):  
Xiang Xie ◽  
Zhongbao Zhao ◽  
Danyong Liu ◽  
Dengwen Zhang ◽  
Yi He ◽  
...  

Abstract Background Reduced levels of myocardial STAT3 activity in diabetic hearts may contribute to the increased susceptibility to ischemia-reperfusion injury (I/RI). The protein mammalian target of rapamycin (mTOR) can regulate metabolism and cell processes and plays major roles in the dynamics of I/RI. However, the role of mTOR in regulation of myocardial STAT3 and thereby affect myocardial I/RI in diabetes at relatively late stages of the disease is unknown. Methods Diabetes was induced by Streptozotocin in Sprague-Dawley rats. Myocardial I/RI was achieved with coronary occlusion for 30 minutes and reperfusion for 2 hours in absence or presence of the mTOR inhibitor rapamycin. In vitro cardiomyocyte hypoxia/re-oxygenation (H/R) was established within H9C2 cells. Results In diabetic rats, the levels of troponin-I (Tn-I), lipid peroxidation products 15-F2t-Isoprostane (15-F2t-Iso) and MDA, and the expression of protein mTOR were all significantly increased,and SOD releasing, the expression of protein phosphorylation of STAT3(p-STAT3-Ser727) were both significantly decreased compared to non-diabetic rats. Myocardial I/RI significantly increased the infract size (IS) and further increased the mTOR activation and decreased p-STAT3-Ser727 compared to diabetic rats. The selective mTOR inhibitor rapamycin reversed these changes and conferred cardioprotective effect. In H9C2 cells, high glucose (HG) significantly increased lactic dehydrogenase (LDH) release, apoptosis cells, ROS release, activation of mTOR, and decreased p-STAT3-Ser727. H/R further increased cellular injury, mTOR knock-down significantly reduced H/R injury. Conclusion Myocardial mTOR was enhanced in diabetes and contributed to I/RI. mTOR inhibition attenuated myocardial I/RI through increasing p-STAT3-Ser727.


2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Anthony D. Foster ◽  
Diego Vicente ◽  
Nicholas Clark ◽  
Crystal Leonhardt ◽  
Eric A. Elster ◽  
...  

Objective. Ischemia-reperfusion injury (IRI) produces systemic inflammation with the potential for causing organ failure in tissues peripheral to the initial site of injury. We speculate that treatment strategies that dampen inflammation may be therapeutically beneficial to either the initial site of injury or peripheral organs. To test this, we evaluated the impact of FTY720-induced sequestration of circulating mature lymphocytes on renal IRI and secondary organ injury. Methods. A microvascular clamp was surgically placed around the left renal pedicle of anesthetized male Sprague-Dawley rats with either vehicle or FTY720 treatment (0.3 mg/kg) intravenously injected after 15 min of ischemia. Blood flow was restored after 60 min. Cohorts of anesthetized rats were euthanized at 6, 24, or 72 hrs with tissue samples collected for analysis. Results. FTY720 treatment resulted in profound T lymphocyte reduction in peripheral blood. Histopathologic examination, clinical chemistries, and gene transcript expression measurements revealed that FTY720 treatment reduced hepatocellular degeneration, reduced serum markers of liver injury (ALT/AST), and reduced the expression of gene targets associated with IRI. Conclusion. These findings support an anti-inflammatory effect of FTY720 in the liver where the expression of genes associated with apoptosis, chemotaxis, and the AP-1 transcription factor was reduced. Findings presented here provide the basis for future studies evaluating FTY720 as a potential therapeutic agent to treat complications resulting from renal IRI.


2015 ◽  
Vol 10 (5) ◽  
pp. 415-429 ◽  
Author(s):  
Giuseppe Paradies ◽  
Valeria Paradies ◽  
Francesca M Ruggiero ◽  
Giuseppe Petrosillo

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