Induction Of Ischemia-reperfusion Injury Research Articles

Time-Restricted Feeding Protects against Renal Ischemia-Reperfusion Injury in Mice.

Ischemia-reperfusion injury (IRI) in the kidneys is a major cause of acute kidney injury (AKI). Time-restricted feeding (TRF), known for its metabolic health benefits and alleviation of various chronic diseases without calorie restriction, was investigated for its potential protective effects against IRI-induced AKI. Male C57BL/6 mice underwent unilateral IRI, with their kidneys collected after two days. For two weeks before IRI induction, the TRF group had unlimited access to standard chow but within an 8-hour feeding window during the dark cycle. The study groups were Control, TRF, IRI, and TRF + IRI. In the TRF + IRI group, tubular damage scores significantly decreased compared to the IRI group. Furthermore, the TRF + IRI mice had lower levels of phosphorylated NF-κB and fewer F4/80-positive macrophages than the IRI group. Oxidative stress markers for lipids and proteins were also notably lower in the TRF + IRI group. Additionally, TUNEL-positive tubular cells and cleaved caspase-3 expression were reduced in the TRF + IRI group. Without calorie restriction, TRF mitigated renal damage by reducing inflammation, oxidative stress, and tubular apoptosis in renal IRI. This suggests that TRF could be a promising dietary strategy to prevent IRI-induced AKI.

Syringic acid loaded silver nanoparticles protects ovarian ischemia-reperfusion injury in rats by inhibiting endoplasmic reticulum stress-mediated apoptosis

In the present study, we investigated the protective effect of syringic acid (SA) loaded silver nanoparticles (AgNPs) on endoplasmic reticulum stress-mediated apoptosis during ovarian ischemia-reperfusion injury (IR) in rats. Initial UV–Vis and FT-IR analysis revealed the presence of the Ag and SA in the SA-AgNPs, respectively. TEM analysis demonstrated the spherical morphology with 10–50 nm of nanoparticle size. Next, we evaluated the protective effect of SA-AgNPs against IR. 15-weeks-old rats were divided into seven groups, as follows: control, AgNPs, SA, IR, AgNPs + IR, SA + IR, and SA + AgNPs + IR. Induction of IR led to a significant increase in apoptotic markers (caspase-3), pro-inflammatory markers (IL-1β, TNF-α, ATF-6, NF- κB-p65, and P2X7R), and endoplasmic reticulum stress marker (IRE1) in ovary tissue. Additionally, a remarkable increase in serum IL-1β and TNF-α were found. Moreover, an increase in serum MDA and decreased endogenous anti-oxidant enzymes, including GSH and SOD were observed. Interestingly, treatment with either AgNPs or SA significantly reduced apoptosis, inflammation, and ER stress markers in IR-induced rats. Nevertheless, discernible effects were detected in rats upon treatment with SA + AgNPs. These findings strongly suggest that syringic acid-loaded silver nanoparticles have a promising therapeutic application in ovarian ischemia-reperfusion (IR) injury.

Effects of fingolimod on heart injury induced by renal ischemia-reperfusion

Background. Renal ischemia-reperfusion injury (IRI) is one of the inevitable complications of surgery. The evidence shows that fingolimod, with its anti-inflammatory effects, can play a protective role in renal IRI. The main aim of the present study was to investigate the role of fingolimod against renal IRI in the heart tissue. Methods. Twenty-four male Wistar rats (220±20g) were treated with a single dose of fingolimod (1mg/kg) by intraperitoneal injection before the induction of kidney IRI. At the end of the reperfusion period, the oxidative stress biomarker (malondialdehyde) and antioxidant biomarkers (catalase, superoxide dismutase, glutathione, glutathione peroxidase, and total antioxidant capacity) were evaluated in the heart tissue. Results. Fingolimod pretreatment could increase cardiac glutathione enzyme activity in the fingolimod+IR group compared to the IR group, which was not statistically significant (P>0.05). The level of total antioxidant capacity in the heart tissue was also significantly increased in the fingolimod+IR group in comparison to the IR group (P<0.05). Conclusion. Fingolimod was able to prevent oxidative stress damage in the heart caused by kidney IR induction by increasing the level of total antioxidant capacity of the heart tissue. It is suggested that future studies evaluate the effects of this drug in clinical trials. Practical Implications. The total antioxidant capacity of the heart, as a distant organ affected by kidney IRI, is increased following fingolimod pre-treatment.

Inhibition of Drp1- Fis1 interaction alleviates aberrant mitochondrial fragmentation and acute kidney injury

BackgroundAcute kidney injury (AKI) is a common clinical disorder with complex etiology and poor prognosis, and currently lacks specific and effective treatment options. Mitochondrial dynamics dysfunction is a prominent feature in AKI, and modulation of mitochondrial morphology may serve as a potential therapeutic approach for AKI.MethodsWe induced ischemia–reperfusion injury (IRI) in mice (bilateral) and Bama pigs (unilateral) by occluding the renal arteries. ATP depletion and recovery (ATP-DR) was performed on proximal renal tubular cells to simulate in vitro IRI. Renal function was evaluated using creatinine and urea nitrogen levels, while renal structural damage was assessed through histopathological staining. The role of Drp1 was investigated using immunoblotting, immunohistochemistry, immunofluorescence, and immunoprecipitation techniques. Mitochondrial morphology was evaluated using confocal microscopy.ResultsRenal IRI induced significant mitochondrial fragmentation, accompanied by Dynamin-related protein 1 (Drp1) translocation to the mitochondria and Drp1 phosphorylation at Ser616 in the early stages (30 min after reperfusion), when there was no apparent structural damage to the kidney. The use of the Drp1 inhibitor P110 significantly improved kidney function and structural damage. P110 reduced Drp1 mitochondrial translocation, disrupted the interaction between Drp1 and Fis1, without affecting the binding of Drp1 to other mitochondrial receptors such as MFF and Mid51. High-dose administration had no apparent toxic side effects. Furthermore, ATP-DR induced mitochondrial fission in renal tubular cells, accompanied by a decrease in mitochondrial membrane potential and an increase in the translocation of the pro-apoptotic protein Bax. This process facilitated the release of dsDNA, triggering the activation of the cGAS-STING pathway and promoting inflammation. P110 attenuated mitochondrial fission, suppressed Bax mitochondrial translocation, prevented dsDNA release, and reduced the activation of the cGAS-STING pathway. Furthermore, these protective effects of P110 were also observed renal IRI model in the Bama pig and folic acid-induced nephropathy in mice.ConclusionsDysfunction of mitochondrial dynamics mediated by Drp1 contributes to renal IRI. The specific inhibitor of Drp1, P110, demonstrated protective effects in both in vivo and in vitro models of AKI.

Neuroprotective effects of the combined treatment of resveratrol and urapidil in experimental cerebral ischemia-reperfusion injury in rats.

To evaluate the neuroprotective effect of resveratrol, urapidil, and a combined administration of these drugs against middle cerebral artery occlusion (MCAO) induced ischemia/reperfusion (IR) injury model in rats. Thirty-five rats were divided into five groups of seven animals each. Animals in IR, IR resveratrol (IRr), IR urapidil (IRu), and IR + combination of resveratrol and urapidil (IRc) were exposed to MCAO induced cerebral ischemia reperfusion injury model. Rats in IRr and IRu groups received 30-mg/kg resveratrol and 5-mg/kg urapidil respectively. Animals in IRc received a combined treatment of both drugs. At the end of the study, brain tissues were used for oxidative stress (malondialdehyde, glutathione, and superoxide dismutase), pro-apoptotic caspase-3, anti-apoptotic Bcl-2, and pro-inflammatory tumor necrosis factor-α cytokine level measurements. The MCAO model successfully replicated IR injury with significant histopathological changes, elevated tissue oxidative stress, and upregulated apoptotic and inflammatory protein expression in IR group compared to control group (p < 0.001). All parameters were significantly alleviated in IRr group compared to IR group (all p < 0.05). In IRu group, all parameters except for caspase-3 and Bcl-2 were also significantly different than IR group (all p < 0.05). The IRc group showed the biggest difference compared to IR group in all parameters (all p < 0.001). The IRc had higher superoxide dismutase and Bcl-2 levels, and lower caspase-3 levels compared to both IRr and IRu groups (all p < 0.05). Also, the IRc group had lower MDA and TNF-α levels compared to IRu group (all p < 0.05). The results indicate that combined treatment of resveratrol and urapidil may be a novel strategy to downregulate neurodegeneration in cerebral IR injury.

Effects of Cilostazol on the Myocardium in an Obese Wistar Rat Model of Ischemia-Reperfusion Injury.

This study aims to determine the protective effect of cilostazol on myocardium in obese Wistar rats with induced ischemia-reperfusion injury (IRI). Four groups with 10 Wistar rats were included: 1] Sham Group: IRI was not established in normal weight-Wistar rats. 2] Control Group: IRI but no cilostazol in normal weight-Wistar rats. 3] Cilostazol in normal weight-Wistar rats: IRI and cilostazol was administered. 4] Cilostazol in obese- Wistar rats: IRI and cilostazol was administered. Tissue adenosine triphosphate (ATP) levels were significantly higher and superoxide dismutase (SOD) levels significantly lower in the control group than in the sham group and normal weight cilostazol group (p=0.024 and p=0.003). Fibrinogen levels were 198 mg/dL in the sham group, 204 mg/dL in the control group, and 187 mg/dL in the normal-weight cilostazol group (p=0.046). Additionally, plasminogen activator inhibitor-1 (PAI-1) levels were significantly higher in the control group (p=0.047). The level of ATP was significantly lower in the normal-weight cilostazol group than in the obese group (104 vs 131.2 nmol/g protein, p=0.043). PAI-1 level was 2.4 ng/mL in the normal weight cilostazol group and 3.7 ng/mL in the obese cilostazol group (p=0.029). Normal-weight Wistar rats with cilostazol had significantly better histologic outcomes than the control group and obese Wistar rats (p=0.001 and p=0.001). Cilostazol has a protective effect on myocardial cells in IRI models by decreasing inflammation. The protective role of cilostazol was reduced in obese Wistar rats compared with normal-weight Wistar rats.

Celery Ethanol Extract Prevents Renal Ischemia-Reperfusion Injury via Increasing Nitrite Oxide and Superoxide Dismutase

Background: Acute kidney injury (AKI) is one of the health problems. Kidney ischemia-reperfusion injury (IRI) contributes to pathological conditions of AKI. An imbalance between renal vasoconstriction and vasodilatation mediators was played a role in IRI and its chronic complications. Stress oxidative and inflammation were major pathomechanism of IRI. Administration of celery ethanol extract is one of the efforts to prevent kidney damage caused by IRI. This study aimed to investigate the time effect of celery ethanol extract administration on inhibition of kidney IRI. Methods: Twenty male Sprague Dawley rats with a weight range of 190-210 g were selected for the study. The rats were divided into five groups randomly: sham operation (SO, n=4) group, IRI group (ischemia-reperfusion injury, n=4), IRI+S7 (celery ethanol extract 1000 mg/kg BW 7 days orally+ischemia-reperfusion injury, n=4), IRI+S14 (celery ethanol extract 1000 mg/kg BW 14 days orally+ischemia-reperfusion injury, n=4), IRI+S28 (celery ethanol extract 1000 mg/kg BW 28 days orally+ischemia-reperfusion injury, n=4). Serum samples were collected for creatinine serum, NO, SOD, and TNF-α measurement. mRNA expression of ET-1 and ETAR was quantified using reverse transcriptase-PCR. Result: Serum creatinine, NO, and SOD level in rats with celery ethanol extract 1000 mg/kg BW for 7 and 14 days administration before IRI induction lower than IRI group (p&lt;0.05) and increase in 28 days administration. Meanwhile, the TNF-α level, ET-1, and ETAR gen expression lower than the IRI group but not significantly different (p&gt;0.05). Conclusion: Administration of celery ethanol extract 1000 mg/kg BW for 7 days and 14 days prevents renal ischemia-reperfusion injury via increasing NO and SOD. Administration more than 28 days is not recommended.

Role of Iberin as an anti-apoptotic agent on renal ischemia-reperfusion injury in rats.

Ischemia-reperfusion injury (IRI) is a major contributor to acute and chronic kidney failure, heart failure, and ischemic stroke. This study aimed to investigate the therapeutic potential of Iberin, known for its anti-inflammatory, antioxidant, and antiapoptotic properties, in a rat model of renal IRI. Twenty-four adult male rats were randomly divided into four groups: Group I (Sham group) underwent laparotomy without IRI induction; Group II (Control group) underwent laparotomy followed by renal artery clamping for 30 minutes to induce ischemia, followed by 2 hours of reperfusion; Group III (Iberin treatment group) received a pre-injection of Iberin (15 mg/kg) and underwent 30 minutes of ischemia followed by 2 hours of reperfusion; and Group IV (Vehicle-treated group) received the vehicle (ethanol) 1 hour prior to ischemia and reperfusion induction. Iberin was diluted with ethanol. Biomarkers associated with inflammation, oxidative stress, and apoptosis were measured using enzyme-linked immunosorbent assay. Iberin treatment significantly reduced levels of inflammatory cytokines interleukin-1β (IL-1β) and IL-6, Bcl-2-associated X protein (BAX), tumor necrosis factor α (TNF-α), nuclear factor kappa p56, high mobility group B1, and neutrophil gelatinase-associated lipocalin. Moreover, Iberin increased levels of heat shock protein and Bcl2 compared to the control and vehicle groups. Iberin treatment prolonged the ischemic tolerance of renal tissue, potentially preventing or delaying irreversible injuries. These findings highlight the potential of Iberin as a promising candidate for mitigating renal injury caused by ischemia-reperfusion, due to its ability to modulate inflammatory markers.

In vivo imaging of renal microvasculature in a murine ischemia–reperfusion injury model using optical coherence tomography angiography

Optical coherence tomography angiography (OCTA) provides three-dimensional structural and semiquantitative imaging of microvasculature in vivo. We developed an OCTA imaging protocol for a murine kidney ischemia–reperfusion injury (IRI) model to investigate the correlation between renal microvascular changes and ischemic damage. Mice were divided into mild and moderate IRI groups according to the duration of ischemia (10 and 35 mins, respectively). Each animal was imaged at baseline; during ischemia; and at 1, 15, 30, 45, and 60 mins after ischemia. Amplitude decorrelation OCTA images were constructed with 1.5-, 3.0-, and 5.8-ms interscan times, to calculate the semiquantitative flow index in the superficial (50–70 μm) and the deep (220–340 μm) capillaries of the renal cortex. The mild IRI group showed no significant flow index change in both the superfial and the deep layers. The moderate IRI group showed a significantly decreased flow index from 15 and 45 mins in the superficial and deep layers, respectively. Seven weeks after IRI induction, the moderate IRI group showed lower kidney function and higher collagen deposition than the mild IRI group. OCTA imaging of the murine IRI model revealed changes in superficial blood flow after ischemic injury. A more pronounced decrease in superficial blood flow than in deep blood flow was associated with sustained dysfunction after IRI. Further investigation on post-IRI renal microvascular response using OCTA may improve our understanding of the relationship between the degree of ischemic insult and kidney function.

Protective effect of IAXO-102 on renal ischemia-reperfusion injury in rats.

Ischemia/reperfusion injury (IRI) is a common cause of kidney damage, characterized by oxidative stress and inflammation. In this study, we investigated the potential protective effects of IAXO-102, a chemical compound, on experimentally induced IRI in male rats. The bilateral renal IRI model was used, with 24 adult male rats randomly divided into four groups (N=6): sham group (laparotomy without IRI induction), control group (laparotomy plus bilateral IRI for 30 minutes followed by 2 hours of reperfusion), vehicle group (same as control but pre-injected with the vehicle), and treatment group (similar to control but pre-injected with IAXO-102). We measured several biomarkers involved in IRI pathophysiology using enzyme-linked immunosorbent assay (ELISA), including High mobility group box1 (HMGB1), nuclear factor kappa b-p65 (NF-κB p65), interleukin beta-1 (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), 8-isoprostane, Bcl-2 associated X protein (BAX), heat shock protein 27 (HSP27), and Bcl-2. Statistical analysis was performed using one-way ANOVA and Tukey post hoc tests. Our results showed that IAXO-102 significantly improved kidney function, reduced histological alterations, and decreased the inflammatory response (IL-1, IL-6, and TNF) caused by IRI. IAXO-102 also decreased apoptosis by reducing pro-apoptotic Bax and increasing anti-apoptotic Bcl-2 without impacting HSP27. In conclusion, our findings suggest that IAXO-102 had a significant protective effect against IRI damage in the kidneys.

Tourniquet-induced ischemia creates increased risk of organ dysfunction and mortality following delayed limb amputation

Tourniquets are critical for the control of traumatic extremity hemorrhage. In this study, we sought to determine, in a rodent blast-related extremity amputation model, the impact of prolonged tourniquet application and delayed limb amputation on survival, systemic inflammation, and remote end organ injury. Adult male Sprague Dawley rats were subjected to blast overpressure (120±7 kPa) and orthopedic extremity injury consisting femur fracture, one-minute soft tissue crush injury (20 psi), ± 180 min of tourniquet-induced hindlimb ischemia followed by delayed (60 min of reperfusion) hindlimb amputation (dHLA). All animals in the non-tourniquet group survived whereas 7/21 (33%) of the animals in the tourniquet group died within the first 72 h with no deaths observed between 72 and 168 h post-injury. Tourniquet induced ischemia-reperfusion injury (tIRI) likewise resulted in a more robust systemic inflammation (cytokines and chemokines) and concomitant remote pulmonary, renal, and hepatic dysfunction (BUN, CR, ALT. AST, IRI/inflammation-mediated genes). These results indicate prolonged tourniquet application and dHLA increases risk of complications from tIRI, leading to greater risk of local and systemic complications including organ dysfunction or death. We thus need enhanced strategies to mitigate the systemic effects of tIRI, particularly in the military prolonged field care (PFC) setting. Furthermore, future work is needed to extend the window within which tourniquet deflation to assess limb viability remains feasible, as well as new, limb-specific or systemic point of care tests to better assess the risks of tourniquet deflation with limb preservation in order to optimize patient care and save both limb and life.

Mitochondrial transplant after ischemia reperfusion promotes cellular salvage and improves lung function during ex-vivo lung perfusion

In lung transplantation, ischemia-reperfusion injury associated with mitochondrial damage can lead to graft rejection. Intact, exogenous mitochondria provide a unique treatment option to salvage damaged cells within lung tissue. We developed a novel method to freeze and store allogeneic mitochondria isolated from porcine heart tissue. Stored mitochondria were injected into a model of induced ischemia-reperfusion injury using porcine ex-vivo lung perfusion. Treatment benefits to immune modulation, antioxidant defense, and cellular salvage were evaluated. These findings were corroborated in human lungs undergoing ex-vivo lung perfusion. Lung tissue homogenate and primary lung endothelial cells were then used to address underlying mechanisms. Following cold ischemia, mitochondrial transplant reduced lung pulmonary vascular resistance and tissue pro-inflammatory signaling and cytokine secretion. Further, exogenous mitochondria reduced reactive oxygen species by-products and promoted glutathione synthesis, thereby salvaging cell viability. These results were confirmed in a human model of ex-vivo lung perfusion wherein transplanted mitochondria decreased tissue oxidative and inflammatory signaling, improving lung function. We demonstrate that transplanted mitochondria induce autophagy and suggest that bolstered autophagy may act upstream of the anti-inflammatory and antioxidant benefits. Importantly, chemical inhibitors of the MEK autophagy pathway blunted the favorable effects of mitochondrial transplant. These data provide direct evidence that mitochondrial transplant improves cellular health and lung function when administered during ex-vivo lung perfusion and suggest the mechanism of action may be through promotion of cellular autophagy. Data herein contribute new insights into the therapeutic potential of mitochondrial transplant to abate ischemia-reperfusion injury during lung transplant, and thus reduce graft rejection.

The roles of AMPK/mTOR autophagy pathway in the acute kidney injury-induced acute lung injury.

Acute kidney injury (AKI) is one of the most challenging clinical problems in kidney disease due to serious complications and high mortality rate, which can lead to acute lung injury (ALI) through inflammatory reactions and oxidative stress. Adenosine monophosphate-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) pathway has been reported to be involved in the development of renal ischemia-reperfusion through autophagy and it remains unclear whether AMPK/mTOR pathway has an effect on the AKI-induced ALI. In this study, we aimed to investigate the effects of autophagy-related AMPK/mTOR signaling pathway on inflammatory factors and oxidative stress in an AKI-induced ALI model. The 48 male Sprague-Dawley rats were divided into four groups randomly: (i) sham, (ii) ischemia/reperfusion injury (IRI), (iii) IRI + rapamycin (RA), and (iv) IRI + 3-methyladenine (3-MA). Unilateral flank incisions were made and right kidneys were excised. The left kidney was subjected to 60 min of ischemia followed by 12, 24, 48, and 72 h of reperfusion. The levels of Scr, blood urea nitrogen (BUN), Wet/Dry ratio, indexes of inflammation, and oxidative stress were assayed. Histological examinations were performed. The protein expression of AMPK, mTOR, LC3-II/LC3-I ratio, and Beclin-1, ULK1 was evaluated by western blotting and immunohistochemistry. Compared to the rats from the sham group, IRI rats showed significantly pulmonary damage after AKI with increased Scr, BUN, Wet/Dry ratio, indexes of inflammation, and oxidative stress. The expression of AMPK, LC3-II/LC3-I ratio, Beclin-1, and ULK1 and were increased, while p62 and mTOR were decreased. In addition, RA treatment significantly attenuated lung injury by promoting autophagy through the activation of the AMPK/mTOR pathway, and 3-MA treatment exhibited adverse effects inversely. Therefore, the activation of the AMPK/mTOR pathway after renal IRI induction could significantly attenuate kidney injury and following AKI-induced ALI by inducing autophagy, which alienates inflammation, oxidative stress, and apoptosis.

Does Ambroxol alleviate kidney ischemia-reperfusion injury in rats?

Objective(s):Ischemia-reperfusion injury is a life-threatening clinical problem that can occur after transplantation or a number of clinical procedures. The purpose of the study was to investigate the effects of Ambroxol on kidney damage caused by experimentally induced ischemia-reperfusion injury in rats. Materials and Methods:Wistar albino rats were divided into 3 groups: Control (CTR, n=6), Kidney ischemia-reperfusion (K-IR, n=6), And kidney ischemia reperfusion+Ambroxol (K-IR+AMB, n=6). In K-IR+AMB group, Ambroxol (30 mg/kg) was administered orally 30 min before the ischemia period. K-IR and K-IR+AMB groups underwent 45 min of kidney ischemia followed by a 6-hour reperfusion period. At the end of the reperfusion period, blood and kidney tissue samples were collected after euthanasia. From the blood samples, BUN and creatinine levels were determined to assess kidney function, and TNF-α and IL-1β concentrations were evaluated to determine inflammatory response. Results:While serum BUN, creatinine activities, and TNF-α and IL-1β concentrations were higher in both IR groups compared with the CTR group, these values were found to be lower in the K-IR+AMB group compared with the K-IR group. Histopathological examination revealed that interstitial edema and desquamation of tubular cells in the K-IR group were more severe than in the K-IR+AMB group. Conclusion:Ambroxol treatment alleviated the production of pro-inflammatory cytokines and the harmful cellular effects in the tubular cells.

Mapping the Diversity of the Innate Immune System over Time After Left Lung Transplantation in Mice

Purpose Following lung transplantation, the surgical intervention with ischemic periods and the foreign allograft are the first to trigger a response from the innate immune system, which represents the primary nonspecific defense against “non-self”. In this study, we investigated the diversity of the emerging innate immune cells and the timing of their appearance in a murine orthotopic left lung transplant model. Methods Mouse orthotopic left lung transplantation was performed in isografts (C57BL/6 to C57BL/6) and allografts (Balbc to C57BL/6). All mice received daily immunosuppression of 10 mg/kg cyclosporin A and 1.6 mg/kg methylprednisolone. Serial sacrifice was performed at day 1, 7 and 35 post-transplantation (n=6 at each time point for each group). Left transplanted lungs were harvested, single cell suspension was made and absolute numbers of innate immune cells were quantified by flow cytometry. Results Following transplantation, isografts and allografts showed an increase in neutrophil (p=0.017) and tissue resident NK cell (p=0.002) numbers at day 1, and in eosinophil (p=0.002) numbers at day 7 post-lung transplant. Granulocytes demonstrated similar patterns in isografts and allografts. Allografts demonstrated an increase in antigen presenting cells i.e. patrolling monocytes (Ly6C-) (p=0.002), interstitial macrophages (p<0.0001) and dendritic cells (p=0.005) at day 7 compared to isografts. Classical NK cells were increased in allografts at day 7 versus isografts (p=0.03). All cell numbers returned to baseline isograft values at day 35 post-transplant, except for dendritic cells (p=0.0045). Conclusion Diverse innate immune cell types show different patterns over time post-lung transplantation depending on transplant induced ischemia-reperfusion injury and/or alloimmune response against the foreign graft. These differences may be very important to dissect the various pathophysiological processes triggered by lung transplantation. Following lung transplantation, the surgical intervention with ischemic periods and the foreign allograft are the first to trigger a response from the innate immune system, which represents the primary nonspecific defense against “non-self”. In this study, we investigated the diversity of the emerging innate immune cells and the timing of their appearance in a murine orthotopic left lung transplant model. Mouse orthotopic left lung transplantation was performed in isografts (C57BL/6 to C57BL/6) and allografts (Balbc to C57BL/6). All mice received daily immunosuppression of 10 mg/kg cyclosporin A and 1.6 mg/kg methylprednisolone. Serial sacrifice was performed at day 1, 7 and 35 post-transplantation (n=6 at each time point for each group). Left transplanted lungs were harvested, single cell suspension was made and absolute numbers of innate immune cells were quantified by flow cytometry. Following transplantation, isografts and allografts showed an increase in neutrophil (p=0.017) and tissue resident NK cell (p=0.002) numbers at day 1, and in eosinophil (p=0.002) numbers at day 7 post-lung transplant. Granulocytes demonstrated similar patterns in isografts and allografts. Allografts demonstrated an increase in antigen presenting cells i.e. patrolling monocytes (Ly6C-) (p=0.002), interstitial macrophages (p<0.0001) and dendritic cells (p=0.005) at day 7 compared to isografts. Classical NK cells were increased in allografts at day 7 versus isografts (p=0.03). All cell numbers returned to baseline isograft values at day 35 post-transplant, except for dendritic cells (p=0.0045). Diverse innate immune cell types show different patterns over time post-lung transplantation depending on transplant induced ischemia-reperfusion injury and/or alloimmune response against the foreign graft. These differences may be very important to dissect the various pathophysiological processes triggered by lung transplantation.

Effect of dexmedetomidine pretreatment on a rat model of myocardial ischemia-reperfusion injury

&#x0D; &#x0D; &#x0D; &#x0D; Purpose: To study the effect of dexmedetomidine pretreatment on a rat model of myocardial ischemia-reperfusion injury (IRI)&#x0D; Methods: Three groups of SD rats (n = 48; mean body weight = 275 ± 25 g) were used (16 rats each): sham, IRI, and dexmedetomidine groups. Ischemia-reperfusion injury (IRI) was established via ligation of left anterior coronary artery. Rats in dexmedetomidine group were treated with single i.p. injection of dexmedetomidine (100 μg/kg) 30 min before induction of IRI. Serum levels of IL-1β, IL-6 and TNF-α were determined by enzyme-linked immunosorbent assay (ELISA). Western blotting was used to determine the protein expressions of bcl-2 and bax, while histopathological changes in rat myocardial tissue were determined with H&amp;E staining.&#x0D; Results: Serum TNF-α, IL-1β and IL-6 levels were significantly up-regulated in IRI rats, relative to sham rats, but were decreased by dexmedetomidine (p &lt; 0.05). Dexmedetomidine significantly reduced the level of malondialdehyde (MDA) in myocardial tissues of IRI rats, but it increased superoxide dismutase (SOD) activity (p &lt; 0.05). It also markedly increased bcl-2 protein level, while the protein expression of bax was decreased (p &lt; 0.05). Results of H &amp; E staining showed that dexmedetomidine significantly mitigated IRI-induced damage.&#x0D; Conclusion: Dexmedetomidine mitigates myocardial IRI in rats through suppression of inflammatory and apoptotic changes, and enhancement of physiological antioxidant potential. This finding may be useful for the management of myocardial ischemia-reperfusion injury.&#x0D; &#x0D; &#x0D; &#x0D;

Fimasartan ameliorates renal ischemia reperfusion injury via modulation of oxidative stress, inflammatory and apoptotic cascades in a rat model.

Ischemia-reperfusion injury (IRI) can be defined as changes in the functions and structures of the tissues resulting from the restoration of blood after a period of ischemia. This study aimed to assess the potential protective effect of Fimasartan (angiotensin receptor antagonist) in the bilateral renal IRI in male rats through its potential effect on renal functions, modulation of the inflammatory cascade, oxidative stress, and apoptotic effect. The animals were equally assigned into four groups. The sham (negative control) group was exposed to surgical conditions without induction of IRI. The control group was exposed to ischemia by occluding the renal pedicles by clamps for 30 min, followed by restoration of blood for 2h. The vehicle-treated group received dimethyl sulfoxide (DMSO) by intraperitoneal injection (IP) 30 minutes before clamping. Fimasartan-treated group: rats pretreated with Fimasartan a dose of 3 mg/kg IP; this was half hour before occluding the renal pedicles. Animals were then exposed to 30 min ischemia (clamping the renal pedicles) followed by 2h reperfusion by releasing the clamps. Blood samples were collected to examine the levels of serum urea and creatinine. Renal tissue was used to measure the levels of cytokines (TNFα, IL-6) and total antioxidant capacity (TAC). Immunohistochemistry was used to assess the levels of Bax, caspase 3, and Bcl-2. Histopathological analyses were performed to detect the parenchymal injury. The present study shows that pretreatment with Fimasartan improves kidney function through its effects on oxidative stress, cytokines, and apoptotic markers.

Effect of Lipopolysaccharide from Rhodobacter sphaeroides on Inflammatory Pathway and Oxidative Stress in Renal Ischemia/Reperfusion Injury in Male Rats.

Ischemia/reperfusion injury (IRI) is caused by a sudden temporary impairment of the blood flow to the particular organ. The IRI of the kidneys is one of the main causes of acute kidney injury. A vigorous inflammatory and oxidative stress response to hypoxia and reperfusion usually happens as IRI consequences that disturb the organ function. The current study aimed to investigate the effect of antagonizing toll-like receptors (TLRs) effects by lipopolysaccharide obtained fromRhodobacter sphaeroides (LPS-RS) on this critical condition. In total, 28 adult male Wistar rats were divided into four groups (n=7) as follows: the sham group which underwent only laparotomy; control group that underwent laparotomy and IRI induction; vehicle group which was similar to the control group plus vehicle treatment, LPS-RS group that was similar to the control group but was pretreated with 0.5 mg/kg of LPS-RS. The results of the current research showed that LPS-RS reduced interleukin-1β, interleukin-6, tumor necrosis factor α, and 8-isoprostane levels, compared to the control IRI group. However, LPS-RS did not ameliorate the kidney injury as manifested by the elevated levels of urea, creatinine, and neutrophil gelatinase-associated lipocalin. Taken together, the present study demonstrated that LPS-RS at the tested dose failed to offer a renoprotective effect against the IRI in rats.

Abstract 14391: Transient Cell Cycle Induction in Cardiomyocytes is a Promising Approach to Treat Ischemia Induced Heart Failure

Rationale: The regenerative capacity of the heart to repair itself after myocardial infarction (MI)is limited. Our previous study showed that ectopic introduction of Cdk1/CyclinB1 andCdk4/CyclinD1 complexes (4F) promotes cardiomyocyte proliferation in vitro and in vivo andimproves cardiac function after MI. However, its clinical application is limited due to the concernsfor tumorigenic potential in other organs. Objectives: To first, identify on a single cell transcriptomic basis the necessary reprogrammingsteps that cardiomyocytes need to undertake to progress through the proliferation processfollowing 4F overexpression, and then, to determine the pre-clinical efficacy of transient andcardiomyocyte specific expression of 4F in improving cardiac function after MI in small and largeanimals. Methods and Results: Temporal bulk and single cell RNAseq of mature hiPS-CMs treated with4F or LacZ control for 24, 48, or 72 h revealed full cell cycle reprogramming in 15% of thecardiomyocyte population which was associated with sarcomere disassembly and metabolicreprogramming. Transient overexpression of 4F specifically in cardiomyocytes was achievedusing non-integrating lentivirus (NIL) driven by TNNT2 (TNNT2-4F-NIL). One week after inductionof ischemia-reperfusion injury in rats or pigs, TNNT2-4F-NIL or control virus was injectedintramyocardially. Compared with controls, rats or pigs treated with TNNT2-4F-NIL showed a 20-30% significant improvement in ejection fraction and scar size four weeks after treatment, asassessed by echocardiography and histological analysis. Quantification of cardiomyocyteproliferation in pigs using a novel cytokinesis reporter showed that ~10% of the cardiomyocyteswithin the injection site were labelled as daughter cells following injection with TNNT2-4F-NILcompared with ~0.5% background labelling in control groups. Conclusions: We provide the first understanding of the process of forced cardiomyocyteproliferation and advanced the clinical applicability of this approach through minimization ofoncogenic potential of the cell cycle factors using a novel transient and cardiomyocyte-specificviral construct.

The possible protective effect of colchicine against liver damage induced by renal ischemia-reperfusion injury: role of Nrf2 and NLRP3 inflammasome.

Ischemia-reperfusion injury (IRI) induces an inflammatory response and production of reactive oxygen species, which affects the organs remote to the sites of renal IR. However, remote effects of renal IRI on the liver need further investigations. Renal injury associated with liver disease is a common clinical problem. Colchicine is an established drug for microtubule stabilization that may reduce tissue injury and has antioxidant and antiinflammatory effects. The aim of the present study was (i) to assess the hepatic changes after induction of renal IRI, (ii) to explore the possible protective effect of colchicine on liver injury following renal IRI, and (iii) to investigate the possible mechanisms underlying the potential effect. Forty rats were randomly divided into four groups: sham operation group, colchicine-treated group, IR group, and colchicine-treated IR group. Colchicine treatment improved liver function (ALT/AST) after renal IRI, decreased hepatic oxidative stress and cell apoptosis by reducing hepatic MDA, upregulating hepatic total antioxidant capacity, Nrf2, and HO-1. Furthermore, colchicine inhibited inflammatory responses by downregulating hepatic NLRP3 inflammasome, IL-1β, and caspase-1. Colchicine attenuates renal IRI-induced liver injury in rats. This effect may be due to reducing inflammation and oxidative stress markers.