OBJECTIVE: To study the protective effect of isoflurane preconditioning on hepatic ischemia-reperfusion (I/R) injury mediated by the noncanonical pyroptosis pathway. METHODS: Thirty C57BL/6 mice were randomly divided into sham-operated group, isoflurane group and I/R group, and in the latter two groups, hepatic I/R injury was induced by clamping the portal vein for 30 min. In isoflurane group, the mice were pretreated with 1.4% isoflurane 30 min before the surgery. The protective effect of isoflurane preconditioning against hepatic I/R injury was evaluated by assessing the pathological score of HE staining of the liver tissue and serum ALT and AST levels. Serum IL-1β and IL-18 levels and the protein expression of GSDMS were detected by ELISA and Western blotting to evaluate the inhibitory effect of isoflurane preconditioning on pyroptosis. Western blotting and immunofluroescence were used to detect the protein expression of caspase-11 in the liver tissues to evaluate the inhibitory effect of isoflurane preconditioning on noncanonical pyroptosis pathway. RESULTS: The Suzuki's score of the liver tissue was significantly higher in I/R group than in the sham group ( < 0.05), while the score in the isoflurane group was significantly lower than that in the I/R group ( < 0.05). Serum ALT and AST levels significantly increased in the sham group ( < 0.05), and were significantly lower in isoflurane group than in I/R group ( < 0.05). The serum levels of IL-1β and IL-18 were significantly higher in I/R group than in sham group ( < 0.05), and were significantly lower in isoflurane group than in I/R group ( < 0.05). The expression of GSDMD in the I/R group was significantly higher than that in sham group, and was significantly lower in isoflurane group than in I/R group ( < 0.05). The hepatic expression of caspase-11 was significantly higher in I/R group than in sham group ( < 0.05), and was significantly lower in isoflurane group than in I/R group ( < 0.05). CONCLUSIONS Isoflurane preconditioning has protective effect against hepatic I/R injury, which is related to the inhibition of the noncanonical pyroptosis pathway.
Animals ; Caspases, Initiator ; Ischemic Preconditioning ; Isoflurane ; Liver ; Mice ; Mice, Inbred C57BL ; Pyroptosis ; Reperfusion Injury

Contrast induced nephropathy (CIN) is acute renal injury following administration of contrast media during angiographic or other medical procedures, which represents as the third cause of hospital-acquired renal failure. CIN is associated with prolonged hospital stay, increased health-care costs, and undesirable clinical outcome. The risk of CIN includes advanced age and diabetes mellitus. With the rapid development of iconography and the wide application of interventional techniques, the patients with CIN are increasing. The preventive measures of CIN include hydration, using appropriate contrast media, stopping nephrotoxic drugs, ischemic preconditioning, renal replacement therapy, and using appropriate drugs. In this paper, the current status and early prevention progress of CIN will be reviewed from three aspects of the high-risk factors, pathogenesis and prevention, aiming to provide guidance for the early prevention of CIN and explore new research directions.
Acute Kidney Injury ; Angiography ; Contrast Media ; Humans ; Ischemic Preconditioning ; Kidney Diseases ; Renal Replacement Therapy ; Risk Factors

PURPOSE: Remote ischemic preconditioning (RIPC), induced by repeated bouts of ischemia followed by reperfusion of the arm or leg is a noninvasive strategy to protect a target organ against oxidative stress and injury caused by ischemia and reperfusion. Interestingly, recent evidence suggests that RIPC may also improve exercise performance by increasing maximal oxygen consumption, but such finding remain equivocal. As such, the purpose of the study was to examine the effect of RIPC on exercise performance in healthy individuals. METHODS: In a randomized cross-over design, 17 healthy male participants (age, 23±3 years) were exposed to either a sham control (six cycles of 5 minutes bilateral thigh cuff occlusion at 20 mm Hg) or RIPC (six cycles of 5 minutes bilateral thigh cuff occlusion at 180 mm Hg) an hour before a maximal exercise test. We measured maximal oxygen consumption, power output, heat rate, blood pressure, and blood lactate as exercise performance parameters during a maximal exercise test performed on an upright bicycle. RESULTS: Compared with the sham control, RIPC improved maximal oxygen consumption (7.4%, p=0.025) and maximal power output (11.5%, p=0.010), whereas other exercise performance parameters remained unchanged with RIPC (p>0.05). CONCLUSION: Taken together, the improvements in maximal oxygen consumption and maximal power output induced by RIPC may suggest that RIPC should be considered as a method for improving exercise performance.
Arm ; Blood Circulation ; Blood Pressure ; Cross-Over Studies ; Exercise Test ; Exercise Tolerance* ; Hot Temperature ; Humans ; Ischemia ; Ischemic Preconditioning* ; Lactic Acid ; Leg ; Male ; Methods ; Oxidative Stress ; Oxygen Consumption ; Reperfusion ; Thigh ; Young Adult*

Ischemic preconditioning (IP) is one of the most important endogenous mechanisms that protect the cells against ischemia-reperfusion (I/R) injury. However, the exact molecular mechanisms remain unclear. In this study, we showed that changes in the level of agmatine were correlated with ischemic tolerance. Changes in brain edema, infarct volume, level of agmatine, and expression of arginine decarboxylase (ADC) and nitric oxide synthases (NOS; inducible NOS [iNOS] and neural NOS [nNOS]) were analyzed during I/R injury with or without IP in the rat brain. After cerebral ischemia, brain edema and infarct volume were significantly reduced in the IP group. The level of agmatine was increased before and during ischemic injury and remained elevated in the early reperfusion phase in the IP group compared to the experimental control (EC) group. During IP, the level of plasma agmatine was increased in the early phase of IP, but that of liver agmatine was abruptly decreased. However, the level of agmatine was definitely increased in the ipsilateral and contralateral hemisphere of brain during the IP. IP also increased the expression of ADC—the enzyme responsible for the synthesis of endogenous agmatine—before, during, and after ischemic injury. In addition, ischemic injury increased endogenous ADC expression in the EC group. The expression of nNOS was reduced in the I/R injured brain in the IP group. These results suggest that endogenous increased agmatine may be a component of the ischemic tolerance response that is induced by IP. Agmatine may have a pivotal role in endogenous ischemic tolerance.
Agmatine* ; Animals ; Arginine ; Brain ; Brain Edema ; Brain Ischemia* ; Ischemic Preconditioning* ; Liver ; Neuroprotection ; Nitric Oxide ; Nitric Oxide Synthase ; Plasma ; Rats ; Reperfusion ; Reperfusion Injury

BACKGROUND: The aim of this study was to investigate the effects of remote ischemic conditioning on ischemia-reperfusion injury in rat muscle flaps histopathologically and biochemically. METHODS: Thirty albino rats were divided into 5 groups. No procedure was performed in the rats in group 1, and only blood samples were taken. A gracilis muscle flap was elevated in all the other groups. Microclamps were applied to the vascular pedicle for 4 hours in order to achieve tissue ischemia. In group 2, no additional procedure was performed. In groups 3, 4, and 5, the right hind limb was used and 3 cycles of ischemia-reperfusion for 5 minutes each (total, 30 minutes) was applied with a latex tourniquet (remote ischemic conditioning). In group 3, this procedure was performed before flap elevation (remote ischemic preconditoning). In group 4, the procedure was performed 4 hours after flap ischemia (remote ischemic postconditioning). In group 5, the procedure was performed after the flap was elevated, during the muscle flap ischemia episode (remote ischemic perconditioning). RESULTS: The histopathological damage score in all remote conditioning ischemia groups was lower than in the ischemic-reperfusion group. The lowest histopathological damage score was observed in group 5 (remote ischemic perconditioning). CONCLUSIONS: The nitric oxide levels were higher in the blood samples obtained from the remote ischemic perconditioning group. This study showed the effectiveness of remote ischemic conditioning procedures and compared their usefulness for preventing ischemia-reperfusion injury in muscle flaps.
Animals ; Extremities ; Ischemia ; Ischemic Preconditioning ; Latex ; Methods* ; Nitric Oxide ; Rats* ; Reperfusion Injury* ; Tourniquets

BACKGROUND: The aim of this study was to investigate the effects of remote ischemic conditioning on ischemia-reperfusion injury in rat muscle flaps histopathologically and biochemically. METHODS: Thirty albino rats were divided into 5 groups. No procedure was performed in the rats in group 1, and only blood samples were taken. A gracilis muscle flap was elevated in all the other groups. Microclamps were applied to the vascular pedicle for 4 hours in order to achieve tissue ischemia. In group 2, no additional procedure was performed. In groups 3, 4, and 5, the right hind limb was used and 3 cycles of ischemia-reperfusion for 5 minutes each (total, 30 minutes) was applied with a latex tourniquet (remote ischemic conditioning). In group 3, this procedure was performed before flap elevation (remote ischemic preconditoning). In group 4, the procedure was performed 4 hours after flap ischemia (remote ischemic postconditioning). In group 5, the procedure was performed after the flap was elevated, during the muscle flap ischemia episode (remote ischemic perconditioning). RESULTS: The histopathological damage score in all remote conditioning ischemia groups was lower than in the ischemic-reperfusion group. The lowest histopathological damage score was observed in group 5 (remote ischemic perconditioning). CONCLUSIONS: The nitric oxide levels were higher in the blood samples obtained from the remote ischemic perconditioning group. This study showed the effectiveness of remote ischemic conditioning procedures and compared their usefulness for preventing ischemia-reperfusion injury in muscle flaps.
Animals ; Extremities ; Ischemia ; Ischemic Preconditioning ; Latex ; Methods* ; Nitric Oxide ; Rats* ; Reperfusion Injury* ; Tourniquets

BACKGROUNDPlasma transfusion is a common clinical practice. Remote ischemic preconditioning (RIPC) protects organs against ischemia-reperfusion (IR) injury. Whether preconditioned plasma (PP), collected at late phase after RIPC, could protect organs against IR injury in vivo is unknown. This study explored whether transfusion of PP could reduce myocardial infarct size (IS) after IR in rat in vivo.

METHODSEighty Lewis rats were randomized to eight groups (n = 10 for each group). Two groups of plasma donor rats donated plasma at 48 h after transient limb ischemia (PP) or control protocol (nonpreconditioned plasma [NPP]). Six groups of recipient rats received normal saline (NS; NS-IR 1, and NS-IR 24 groups), NPP (NPP-IR 1 and NPP-IR 24 groups), or PP (PP-IR 1 and PP-IR 24 groups) at one or 24 h before myocardial IR. Myocardial IR consisted of 30-min left anterior descending (LAD) coronary artery occlusion and 180-min reperfusion. The area at risk (AAR) and infarct area were determined by double-staining with Evans blue and triphenyltetrazolium chloride. IS was calculated by infarct area divided by AAR. This was a 3 × 2 factorial design study, and factorial analysis was used to evaluate the data. If an interaction between the fluid and transfusion time existed, one-way analysis of variance with Bonferroni correction for multiple comparisons was used to analyze the single effects of fluid type when the transfusion time was fixed.

RESULTSIS in the NPP-IR 1 and PP-IR 1 groups was smaller than in the NS-IR 1 group (F = 6.838, P = 0.005; NPP-IR 1: 57 ± 8% vs. NS-IR1: 68 ± 6%, t = 2.843, P = 0.020; PP-IR 1: 56 ± 8% vs. NS-IR 1: 68 ± 6%, t = 3.102, P = 0.009), but no significant difference was detected between the NPP-IR 1 and PP-IR 1 groups (57 ± 8% vs. 56 ± 8%, t = 0.069, P = 1.000). IS in the NPP-IR 24 and PP-IR 24 groups was smaller than in the NS-IR 24 group (F = 24.796, P< 0.001; NPP-IR 24: 56% ± 7% vs. NS-IR 24: 68 ± 7%, t = 3.102, P = 0.026; PP-IR 24: 40 ± 9% vs. NS-IR 24: 68 ± 7%, t = 7.237, P< 0.001); IS in the PP-IR 24 group was smaller than in the NPP-IR 24 group (40 ± 9% vs. 56 ± 7%, t = 4.135, P = 0.002).

CONCLUSIONTransfusion of PP collected at late phase after remote ischemic preconditioning could reduce IS, suggesting that late-phase cardioprotection was transferable in vivo.

Animals ; Blood Component Transfusion ; methods ; Ischemic Preconditioning, Myocardial ; methods ; Male ; Myocardial Infarction ; etiology ; prevention & control ; Myocardial Reperfusion Injury ; complications ; Plasma ; Rats

PURPOSE: The aim of the present study was to investigate the protective effects of ischemic preconditioning for different periods of time and to elucidate the optimal safe ischemic preconditioning time for renal ischemia-reperfusion (I/R) injury in mice. METHODS: A total of 25 male C57BL/6 mice were randomly divided into 5 groups (sham, I/R, ischemic preconditioning [IP]-3, IP-5, and IP-7 groups), in which the kidney was preconditioned with IP of various durations and then subjected to I/R injury (the last 3 groups). To induce renal ischemia, the left renal pedicle was occluded with a nontraumatic microaneurysm clamp for 30 minutes followed by reperfusion for 24 hours. The effects of IP on renal I/R injury were evaluated in terms of renal function, tubular necrosis, apoptotic cell death and inflammatory cytokines. RESULTS: Results indicated that BUN and creatinine (Cr) levels increased significantly in the I/R group, but the elevations were significantly lower in IP groups, especially in the IP-5 group. Histological analysis revealed that kidney injury was markedly decreased in the IP-5 group compared with the I/R group, as evidenced by reduced renal necrosis/apoptosis. In addition, IP significantly inhibited gene expression of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) and chemokines (monocyte chemoattractant protein-1). Western blot analysis indicated that the expression levels of Toll-like receptor 4 (TLR4) and nuclear factor-kappa B (NF-κB) were upregulated in the I/R group, while expression was inhibited in the IP groups. CONCLUSION: Five-minute IP had the greatest protective effect against I/R injury.
Animals ; Blotting, Western ; Cell Death ; Chemokines ; Creatinine ; Cytokines ; Gene Expression ; Humans ; Ischemia ; Ischemic Preconditioning* ; Kidney ; Male ; Mice* ; Necrosis ; Reperfusion ; Reperfusion Injury* ; Toll-Like Receptor 4

Remote ischemic preconditioning (RIPC) is an intrinsic phenomenon whereby 3~4 consecutive ischemia-reperfusion cycles to a remote tissue (noncardiac) increases the tolerance of the myocardium to sustained ischemiareperfusion induced injury. Remote ischemic preconditioning induces the local release of chemical mediators which activate the sensory nerve endings to convey signals to the brain. The latter consequently stimulates the efferent nerve endings innervating the myocardium to induce cardioprotection. Indeed, RIPC-induced cardioprotective effects are reliant on the presence of intact neuronal pathways, which has been confirmed using nerve resection of nerves including femoral nerve, vagus nerve, and sciatic nerve. The involvement of neurogenic signaling has been further substantiated using various pharmacological modulators including hexamethonium and trimetaphan. The present review focuses on the potential involvement of neurogenic pathways in mediating remote ischemic preconditioning-induced cardioprotection.
Brain ; Femoral Nerve ; Hexamethonium ; Ischemic Preconditioning* ; Myocardium ; Negotiating ; Nerve Endings ; Neurons ; Sciatic Nerve ; Sensory Receptor Cells ; Trimethaphan ; Vagus Nerve

PURPOSE: Ischemic preconditioning (IPC), including remote IPC (rIPC) and direct IPC (dIPC), is a promising method to decrease ischemia-reperfusion (IR) injury. This study tested the effect of both rIPC and dIPC on the genes for antioxidant enzymes and endoplasmic reticulum (ER) stress-related proteins. MATERIALS AND METHODS: Twenty rats were randomly divided into the control and study groups. In the control group (n=10), the right hind limb was sham-operated. The left hind limb (IscR) of the control group underwent IR injury without IPC. In the study group (n=10), the right hind limb received IR injury after 3 cycles of rIPC. The IscR received IR injury after 3 cycles of dIPC. Gene expression was analyzed by Quantitative real-time polymerase chain reaction from the anterior tibialis muscle. RESULTS: The expression of the antioxidant enzyme genes including glutathione peroxidase (GPx), superoxide dismutase (SOD) 1 and catalase (CAT) were significantly reduced in IscR compared with sham treatment. In comparison with IscR, rIPC enhanced the expression of GPx, SOD2, and CAT genes. dIPC enhanced the expression of SOD2 and CAT genes. The expression of SOD2 genes was consistently higher in rIPC than in dIPC, but the difference was only significant for SOD2. The expression of genes for ER stress-related proteins tended to be reduced in IscR in comparison with sham treatment. However, the difference was only significant for C/EBP homologous protein (CHOP). In comparison with IscR, rIPC significantly up-regulated activating transcription factor 4 and CHOP, whereas dIPC up-regulated CHOP. CONCLUSION: Both rIPC and dIPC enhanced expression of genes for antioxidant enzymes and ER stress-related proteins.
Activating Transcription Factor 4 ; Animals ; Catalase ; Cats ; Endoplasmic Reticulum* ; Extremities ; Gene Expression ; Glutathione Peroxidase ; Ischemic Preconditioning* ; Methods ; Muscle, Skeletal* ; Placebos ; Rats* ; Real-Time Polymerase Chain Reaction ; Reperfusion Injury ; Superoxide Dismutase