Polyethylene glycol fusion repair of severed sciatic nerves accelerates recovery of nociceptive sensory perceptions in male and female rats of different strains

Successful polyethylene glycol fusion(PEG-fusion)of severed axons following peripheral nerve injuries for PEG-fused axons has been reported to:(1)rapidly restore electrophysiological continuity;(2)prevent distal Wallerian Degeneration and maintain their myelin sheaths;(3)promote primarily motor,voluntary behavioral recoveries as assessed by the Sciatic Functional Index;and,(4)rapidly produce correct and incorrect connections in many possible combinations that produce rapid and extensive recovery of functional peripheral nervous system/central nervous system connections and reflex(e.g.,toe twitch)or voluntary behaviors.The preceding companion paper describes sensory terminal field reo rganization following PEG-fusion repair of sciatic nerve transections or ablations;howeve r,sensory behavioral recovery has not been explicitly explored following PEG-fusion repair.In the current study,we confirmed the success of PEG-fusion surgeries according to criteria(1-3)above and more extensively investigated whether PEG-fusion enhanced mechanical nociceptive recovery following sciatic transection in male and female outbred Sprague-Dawley and inbred Lewis rats.Mechanical nociceptive responses were assessed by measuring withdrawal thresholds using von Frey filaments on the dorsal and midplantar regions of the hindpaws.Dorsal von Frey filament tests were a more reliable method than plantar von Frey filament tests to assess mechanical nociceptive sensitivity following sciatic nerve transections.Baseline withdrawal thresholds of the sciatic-mediated lateral dorsal region differed significantly across strain but not sex.Withdrawal thresholds did not change significantly from baseline in chronic Unoperated and Sham-operated rats.Following sciatic transection,all rats exhibited severe hyposensitivity to stimuli at the lateral dorsal region of the hindpaw ipsilateral to the injury.However,PEG-fused rats exhibited significantly earlier return to baseline withdrawal thresholds than Negative Control rats.Furthermore,PEG-fused rats with significantly improved Sciatic Functional Index scores at or after 4 weeks postoperatively exhibited yet-earlier von Frey filament recove ry compared with those without Sciatic Functional Index recovery,suggesting a correlation between successful PEG-fusion and both motor-dominant and sensory-dominant behavioral recoveries.This correlation was independent of the sex or strain of the rat.Furthermore,our data showed that the acceleration of von Frey filament sensory recovery to baseline was solely due to the PEG-fused sciatic nerve and not saphenous nerve collateral outgrowths.No chronic hypersensitivity developed in any rat up to 12 weeks.All these data suggest that PEG-fusion repair of transection peripheral nerve injuries co uld have important clinical benefits.

Polyethylene glycol fusion repair of severed rat sciatic nerves reestablishes axonal continuity and reorganizes sensory terminal fields in the spinal cord

Peripheral nerve injuries result in the rapid degeneration of distal nerve segments and immediate loss of motor and sensory functions;behavioral recovery is typically poor.We used a plasmalemmal fusogen,polyethylene glycol(PEG),to immediately fuse closely apposed open ends of severed proximal and distal axons in rat sciatic nerves.We have previously reported that sciatic nerve axons repaired by PEG-fusion do not undergo Wallerian degeneration,and PEG-fused animals exhibit rapid(within 2–6 weeks)and extensive locomotor recovery.Furthermore,our previous report showed that PEG-fusion of severed sciatic motor axons was non-specific,i.e.,spinal motoneurons in PEG-fused animals were found to project to appropriate as well as inappropriate target muscles.In this study,we examined the consequences of PEG-fusion for sensory axons of the sciatic nerve.Young adult male and female rats(Sprague–Dawley)received either a unilateral single cut or ablation injury to the sciatic nerve and subsequent repair with or without(Negative Control)the application of PEG.Compound action potentials recorded immediately after PEG-fusion repair confirmed conduction across the injury site.The success of PEG-fusion was confirmed through Sciatic Functional Index testing with PEG-fused animals showing improvement in locomotor function beginning at 35 days postoperatively.At 2–42 days postoperatively,we anterogradely labeled sensory afferents from the dorsal aspect of the hindpaw following bilateral intradermal injection of wheat germ agglutinin conjugated horseradish peroxidase.PEG-fusion repair reestablished axonal continuity.Compared to unoperated animals,labeled sensory afferents ipsilateral to the injury in PEG-fused animals were found in the appropriate area of the dorsal horn,as well as inappropriate mediolateral and rostrocaudal areas.Unexpectedly,despite having intact peripheral nerves,similar reorganizations of labeled sensory afferents were also observed contralateral to the injury and repair.This central reorganization may contribute to the improved behavioral recovery seen after PEG-fusion repair,supporting the use of this novel repair methodology over currently available treatments.

Polyethylene glycol has immunoprotective effects on sciatic allografts, but behavioral recovery and graft tolerance require neurorrhaphy and axonal fusion

Behavioral recovery using(viable)peripheral nerve allografts to repair ablation-type(segmental-loss)peripheral nerve injuries is delayed or poor due to slow and inaccurate axonal regeneration.Furthermore,such peripheral nerve allografts undergo immunological rejection by the host immune system.In contrast,peripheral nerve injuries repaired by polyethylene glycol fusion of peripheral nerve allografts exhibit excellent behavioral recovery within weeks,reduced immune responses,and many axons do not undergo Wallerian degeneration.The relative contribution of neurorrhaphy and polyethylene glycol-fusion of axons versus the effects of polyethylene glycol per se was unknown prior to this study.We hypothesized that polyethylene glycol might have some immune-protective effects,but polyethylene glycol-fusion was necessary to prevent Wallerian degeneration and functional/behavioral recovery.We examined how polyethylene glycol solutions per se affect functional and behavioral recovery and peripheral nerve allograft morphological and immunological responses in the absence of polyethylene glycol-induced axonal fusion.Ablation-type sciatic nerve injuries in outbred Sprague–Dawley rats were repaired according to a modified protocol using the same solutions as polyethylene glycol-fused peripheral nerve allografts,but peripheral nerve allografts were loose-sutured(loose-sutured polyethylene glycol)with an intentional gap of 1–2 mm to prevent fusion by polyethylene glycol of peripheral nerve allograft axons with host axons.Similar to negative control peripheral nerve allografts not treated by polyethylene glycol and in contrast to polyethylene glycol-fused peripheral nerve allografts,animals with loose-sutured polyethylene glycol peripheral nerve allografts exhibited Wallerian degeneration for all axons and myelin degeneration by 7 days postoperatively and did not recover sciatic-mediated behavioral functions by 42 days postoperatively.Other morphological signs of rejection,such as collapsed Schwann cell basal lamina tubes,were absent in polyethylene glycol-fused peripheral nerve allografts but commonly observed in negative control and loose-sutured polyethylene glycol peripheral nerve allografts at 21 days postoperatively.Loose-sutured polyethylene glycol peripheral nerve allografts had more pro-inflammatory and less anti-inflammatory macrophages than negative control peripheral nerve allografts.While T cell counts were similarly high in loose-sutured-polyethylene glycol and negative control peripheral nerve allografts,loose-sutured polyethylene glycol peripheral nerve allografts expressed some cytokines/chemokines important for T cell activation at much lower levels at 14 days postoperatively.MHCI expression was elevated in loose-sutured polyethylene glycol peripheral nerve allografts,but MHCII expression was modestly lower compared to negative control at 21 days postoperatively.We conclude that,while polyethylene glycol per se reduces some immune responses of peripheral nerve allografts,successful polyethylene glycol-fusion repair of some axons is necessary to prevent Wallerian degeneration of those axons and immune rejection of peripheral nerve allografts,and produce recovery of sensory/motor functions and voluntary behaviors.Translation of polyethylene glycol-fusion technologies would produce a paradigm shift from the current clinical practice of waiting days to months to repair ablation peripheral nerve injuries.

Molecular Dynamics-Based Simulation of Polyethylene Pipe Degradation in High Temperature and High Pressure Conditions

High-density polyethylene(HDPE)pipes have gradually become the first choice for gas networks because of their excellent characteristics.As the use of pipes increases,there will unavoidably be a significant amount of waste generated when the pipes cease their operation life,which,if improperly handled,might result in major environmental contamination issues.In this study,the thermal degradation of polyethylene materials is simulated for different pressures(10,50,100,and 150 MPa)and temperatures(2300,2500,2700,and 2900 K)in the framework of Reactive Force Field(ReaxFF)molecular dynamics simulation.The main gas products,density,energy,and the mean square displacement with temperature and pressure are also calculated.The findings indicate that raising the temperature leads to an increase in the production of gas products,while changing the pressure has an impact on the direction in which the products are generated;the faster the temperature drops,the less dense the air;both temperature and pressure increase impact the system’s energy conversion or distribution mechanism,changing the system’s potential energy as well as its total energy;the rate at which molecules diffuse increases with temperature,and decreases with pressure.The results of this investigation provide a theoretical basis for the development of the pyrolytic treatment of polyethylene waste materials.

Detection of internal crack growth in polyethylene pipe using guided wave ultrasonic testing

Despite the success of guided wave ultrasonic inspection for internal defect detection in steel pipes,its application on polyethylene(PE)pipe remains relatively unexplored.The growth of internal cracks in PE pipe severely affects its pressure-holding capacity,hence the early detection of internal cracks is crucial for effective pipeline maintenance strategies.This study extends the scope of guided wave-based ultrasonic testing to detect the growth of internal cracks in a natural gas distribution PE pipe.Laboratory experiments and a finite element model were planned to study the wave-crack interaction at different stages of axially oriented internal crack growth with a piezoceramic transducer-based setup arranged in a pitch-catch configuration.Mode dispersion analysis supplemented with preliminary experiments was performed to isolate the optimal inspection frequency,leading to the selection of the T(0,1)mode at 50-kHz for the investigation.A transmission index based on the energy of the T(0,1)mode was developed to trace the extent of simulated crack growth.The findings revealed an inverse linear correlation between the transmission index and the crack depth for crack growth beyond 20%crack depth.

Experimental Study of the Influence of Intrinsic Parameters on the Thermal Reactivity of Sawdust, Polyethylene Terephthalate and Composite

Several works have been based on the study of thermal variations in biomass to derive more valuable products such as fuels capable of replacing oil in the event of a crisis or activated carbon used as an adsorbent material, widely used in industry for the elimination of unwanted materials, both in liquid and gaseous environments. A study of thermal parameters such as: heating speed, retention time, drying temperature, carbonization temperature, particle size, was carried out with the aim of determining the characteristic factors of the carbonization of Polyethylene terephthalate (PET), sawdust (SC) and sawdust/polyethylene terephthalate (CPS) mixture. The results of the immediate analysis revealed a very low level of ash in PET (0.013%) compared to the level of ash in sawdust (2.9%), as well as a high level of fixed carbon (82.960%), which suggests the presence of mineral oxides and a significant carbon matrix unlike PET, which indicates a very significant organic matrix (essentially made up of organic matter) with the absence of mineral oxides. The study of thermal parameters showed the water loss from Sawdust (SC) and the Sawdust/Polyethylene terephthalate (CPS) mixture, an increase with temperature, unlike that of PET whose variation is essentially zero. Without heat treatment, sawdust alone contains approximately 7% water. The optimal drying temperature for this study is 110˚C for a stay of 24 hours. It appears that the largest mass losses for the PET samples are between 87.19% and 96.05%, followed by that of the mixture, between 47.33% and 64.37%. And the lowest are observed, those of sawdust (from 24.02% to 62.6%). However, here we can say that the influence of the mass is not great, given the slight difference between the losses by temperature. The results of the study of the influence of grain size showed that the differences are insignificant, even if we vary the diameter of the grains from simple to triple. To better minimize physical constraints such as the intragranular diffusibility of the volatile matter and the homogeneity of the temperature in the grains, 75 μm particles are found to be optimal for our study. It can be noted when studying the heating rate that the mass loss at the end of the reaction is approximately the same depending on each precursor material. However, it has been demonstrated that the heating rate strongly influences the nature of the reaction products both for volatile materials and for the solid residue as well as on the kinetic parameters of the chemical reaction. Furthermore, the variation in apparent density shows a decrease as a function of the increase in the residence time of the materials in the reactor. As the carbonization time increases, the apparent density decreases. We note, for the lignocellulosic material, that the apparent density stabilizes after 60 minutes.

Enhancing performance of low-temperature processed CsPbI2Br all-inorganic perovskite solar cells using polyethylene oxide-modified TiO_(2)

CsPbX_(3)-based(X=I,Br,Cl)inorganic perovskite solar cells(PSCs)prepared by low-temperature process have attracted much attention because of their low cost and excellent thermal stability.However,the high trap state density and serious charge recombination between low-temperature processed TiO_(2)film and inorganic perovskite layer interface seriously restrict the performance of all-inorganic PSCs.Here a thin polyethylene oxide(PEO)layer is employed to modify TiO_(2)film to passivate traps and promote carrier collection.The impacts of PEO layer on microstructure and photoelectric characteristics of TiO_(2)film and related devices are systematically studied.Characterization results suggest that PEO modification can reduce the surface roughness of TiO_(2)film,decrease its average surface potential,and passivate trap states.At optimal conditions,the champion efficiency of CsPbI_(2)Br PSCs with PEO-modified TiO_(2)(PEO-PSCs)has been improved to 11.24%from 9.03%of reference PSCs.Moreover,the hysteresis behavior and charge recombination have been suppressed in PEO-PSCs.

Preparation of carbon nanotube-reinforced polyethylene nanocomposites with better antiscaling and corrosion-resistant properties

Anti-scaling technology for pipelines has always been a focus of oilfield industrial production.Compared with traditional metal pipes,polyethylene(PE)pipes have unique advantages in terms of corrosion resistance,surface friction resistance,and service life.In this paper,aiming at an enhancement of antiscaling and corrosion-resistant properties,as well as increased mechanical properties,PE nanocomposites have been prepared by the introduction of modified carbon nanotubes(m-CNTs)into the PE matrix.To improve the interface compatibility of the composites,the CNTs were treated with reactive tetrabutyl titanate after nitric acid oxidation,which brings about uniform dispersion of the CNTs and intimate interface interaction.As the m-CNT fraction increases,the PE crystallinity displays a slight increase.Polarized microscopy shows that the scaling on the surface of the composite material is obviously reduced compared with pure PE,because the surface free energy of the composite material decreases.Moreover,due to the good dispersion,the composites show enhanced mechanical properties.That is,by adding 1.10 wt%CNTs,the tensile stress and impact toughness of the composites are 20.76 MPa and 37.89 kJ m^(-2),respectively,increases of 15.0% and 11.9% compared with pure PE.This paper supports the idea that the crystallinity of the PE matrix can be improved by adding CNTs,thereby increasing the corrosion resistance and anti-scaling properties.This work can provide inspiration for using the methods of scale inhibition and corrosion resistance in polymer nanocomposites.

Photocatalystic Oxidation Degradation of Polyethylene by Nano-TiO_2 Doped Rare Earth Ion

Nano-sized TiO2 doped La^3＋ , was used as photocatalysis to degrade polyethylene （PE） film in solid-state reaction. It made PE lose its mass fraction of 14.5%, and formed more quantities of CO2 and more wax yields after UV irradiation for 288 h. SEM imagines displayed more and bigger holes and pits in the PE film. FT-IR spectra showed that there is a lower absorbance of groups of - CH2 and - CH3 in PE/ TiO2 and 0. 1% La2O3/TiO2/PE composite materials than that in PE film sample of photodegradation, and more carbonyl groups in PE/0.1% LaEO3/TiO2. La^3＋ doping TiO2 improves TiO2 activities of oxidation and erosion of PE film under UV irradiation.

STUDY ON DEGRADATION OF POLYETHYLENE FILMS CONTAINING ADDITIVES WITH FERROUS ION AT COMPOSTING TEMPERATURES

Polyethylene (PE) films with additives consisting mainly of oleic acid and ferrous ions were subjected to accelerated degradation at simulated composting temperatures.Based on Fourier transform infrared spectroscopy and measurements of mechanical properties and viscosity average molecular weight,the degradation of the films was characterized and the degradation mechanism was discussed.The films containing additives with ferrous ions represent considerable decreases in molecular weight,and the carbonyl groups and hydroperoxides in the aging films show different trends of increase with the aging time.These results indicate that the ferrous ion plays an important role in the degradation of PE films and accelerates the degradation of PE.

Polyethylene glycol (PEG) as a benign solvent for Knoevenagel condensation

The Knoevenagel condensation of aromatic aldehydes with active methylene compound proceeded efficiently in polyethylene glycol at room temperature with L-proline as catalyst. The yield is high and the products had E-isomer dominantly. Polyethylene glycol containing L-proline could be recycled and reused for several times without noticeably decreasing in productivity.

Surface Modification of Polyethylene (PE) Films Using Dielectric Barrier Discharge Plasma at Atmospheric Pressure

Modification of the surface properties of polyethylene （PE） films is studied using air dielectric barrier discharge at atmospheric pressure. The treated samples are examined by Water contact angle measurements, Fourier transform infrared attenuated total reflection spectroscopy （FTIR-ATR）, X-ray photoelectron spectroscopy （XPS） and scanning electron microscopy （SEM）. With the increase in treating time, the water contact angle changes from 93.2° before treatment to a minimum of 53.3° after a treatment for 50 s. Both ATR and XPS results show some oxidized species are introduced into the sample surface by the plasma treatment and the tendency of the water contact angle with the treating time is the same as that of oxygen concentration on the treated sample surface. SEM result shows the surface roughness of PE samples increases with the treatment time increasing.

Conundrums and confusions regarding how polyethylene glycol-fusion produces excellent behavioral recovery after peripheral nerve injuries

Current Neuroscience dogma holds that transections or ablations of a segment of peripheral nerves produce： （1） Immediate loss of axonal continuity, sensory signaling, and motor control; （2） Wallerian rapid （1-3 days） degeneration of severed distal axons, muscle atrophy, and poor behavioral recovery after many months （if ever, after ablations） by slowly-regenerating （1 mm/d）, proximal-stump outgrowths that must specifically reinnervate denervated targets; （3） Poor acceptance of microsutured nerve allografts, even if tissue-matched and immune-suppressed. Repair of transections/ablations by neurorrhaphy and well-specified-sequences of PEG-fusion solutions （one containing polyethylene glycol, PEG） successfully address these problems. However, conundrums and confusions regarding unorthodox and dramatic results of PEG-fusion repair in animal model systems often lead to misunderstandings. For example, （1） Axonal continuity and signaling is re-established within minutes by non-specifically PEG-fusing （connecting） severed motor and sensory axons across each lesion site, but remarkable behavioral recovery to near-unoperated levels takes several weeks; （2） Many distal stumps of inappropriately-reconnected, PEG-fused axons do not ever （Wallerian） degenerate and continuously innervate muscle fibers that undergo much less atrophy than otherwise-denervated muscle fibers; （3） Host rats do not reject PEG-fused donor nerve allografts in a non-immuno-privileged environment with no tissue matching or immunosuppression; （4） PEG fuses apposed open axonal ends or seals each shut （thereby preventing PEG-fusion）, depending on the experimental protocol; （5） PEG-fusion protocols produce similar results in animal model systems and early human case studies. Hence, iconoclastic PEG-fusion data appropriately understood might provoke a re-thinking of some Neuroscience dogma and a paradigm shift in clinical treatment of peripheral nerve injuries.

PREPARATION OF MICROPOROUS ULTRA HIGH MOLECULAR WEIGHT POLYETHYLENE (UHMWPE) BY THERMALLY INDUCED PHASE SEPARATION OF A UHMWPE/LIQUID PARAFFIN MIXTURE

Ultra-high molecular weight polyethylene (UHMWPE) with a microporous structure was prepared via thermally induced phase separation (TIPS).Liquid paraffin (LP) was used as a diluent in the preparation of microporous UHMWPE. Small angle laser light scattering (SALLS) and differential scanning calorimetry (DSC) were used to determine the phase separation temperatures,i.e.the cloud points and the dynamic crystallization temperatures,respectively.It was found that the cloudI points were coincident with the cryst...

MECHANICAL PROPERTIES OF SMC WHISKER REINFORCED HIGH DENSITY POLYETHYLENE COMPOSITES

A new type of SiO_2-MgO-CaO (SMC) whisker was used to modify high density polyethylene (HDPE).The melting behavior and crystallinity were investigated by differential scanning calorimetry (DSC).The dispersion of whiskers and interfacial adhesion in the prepared HDPE/SMC whisker composites were investigated by scanning electron microscopy (SEM).The mechanical properties were evaluated by mechanical tests and dynamic mechanical analysis (DMA).DSC data indicated that the melting temperature and the crystallini...

Boerhaave's syndrome during bowel preparation with polyethylene glycol in a patient with postpolypectomy bleeding

Boerhaave's syndrome is spontaneous rupture of the esophagus,a rare condition with high mortality that occurs most often after forceful vomiting.Polyethylene glycol(PEG) solution is the most common preparation used for colonoscopy.Since large volumes have to be ingested,PEG may induce severe vomiting or retching.However,Boerhaave's syndrome has rarely been reported as a potential problem related to PEG solution.We report a case of spontaneous esophageal rupture due to violent vomiting during bowel preparation with PEG solution in a patient with postpolypectomy bleeding.

Role of polyethylene particles in peri-prosthetic osteolysis:A review

There is convincing evidence that particles produced by the wear of joint prostheses are causal in the periprosthetic loss of bone,or osteolysis,which,if it progresses,leads to the phenomenon of aseptic loosening.It is important to fully understand the biology of this bone loss because it threatens prosthesis survival,and loosened implants can result in peri-prosthetic fracture,which is disastrous for the patient and presents a difficult surgical scenario.The focus of this review is the bioactivity of polyethylene(PE)particles,since there is evidence that these are major players in the development and progression of osteolysis around prostheses which use PE as the bearing surface.The review describes the biological consequences of interaction of PE particles with macrophages,osteoclasts and cells of the osteoblast lineage,including osteocytes.It explores the possible cellular mechanisms of action of PE and seeks to use the findings to date to propose potential nonsurgical treatments for osteolysis.In particular,a nonsurgical approach is likely to be applicable to implants containing newer,highly cross-linked PEs(HXLPEs),for which osteolysis seems to occur with much reduced PE wear compared with conventional PEs.The caveat here is that we know little as yet about the bioactivity of HXLPE particles and addressing this constitutes our next challenge.

PREPARATION OF HIGH DENSITY POLYETHYLENE/POLYETHYLENE-BLOCK-POLY(ETHYLENE GLYCOL)COPOLYMER BLEND POROUS MEMBRANES VIA THERMALLY INDUCED PHASE SEPARATION PROCESS AND THEIR PROPERTIES

High density polyethylene （HDPE）/polyethylene-block-poly（ethylene glycol） （PE-b-PEG） blend porous membranes were prepared via thermally induced phase separation （TIPS） process using diphenyl ether （DPE） as diluent. The phase diagrams of HDPE/PE-b-PEG/DPE systems were determined by optical microscopy and differential scanning calorimetry （DSC）. By varying the content of PE-b-PEG, the effects of PE-b-PEG copolymer on morphology and crystalline structure of membranes were studied by scanning electron microscopy （SEM） and wide angle X-ray diffraction （WAXD）. The chemical compositions of whole membranes and surface layers were characterized by elementary analysis, Fourier transform infrared spectroscopy-attenuated total reflection （FTIR-ATR） and X-ray photoelectron spectroscopy （XPS）. Water contact angle, static protein adsorption and water flux experiments were used to evaluate the hydrophilicity, antifouling and water permeation properties of the membranes. It was found that the addition of PE-b-PEG increased the pore size of the obtained blend membranes. In the investigated range of PE-b-PEG content, the PEG blocks could not aggregate into obviously separated domains in membrane matrix. More importantly, PE-b-PEG could not only be retained stably in the membrane matrix during membrane formation, but also enrich at the membrane surface layer. Such stability and surface enrichment of PE-b-PEG endowed the blend membranes with improved hydrophilicity, protein absorption resistance and water permeation properties, which would be substantially beneficial to HDPE membranes for water treatment application.

EFFECTS OF COMPATIBILIZERS ON THE MECHANICAL PROPERTIES OF LOW DENSITY POLYETHYLENE/LIGNIN BLENDS

Low density polyethylene(LDPE)/lignin blends were prepared using melt blending.Two kinds of compatibilizers, ethylene-vinylacetate(EVA) which is softer than LDPE and polyethylene grafted with maleic anhydride(PE-g-MA) which is harder than LDPE were used to improve the interfacial adhesion.Scanning electron microscope(SEM) was used to investigate the dispersion of lignin in LDPE matrix.The results showed that both of the compatibilizers could improve the interaction between the low density polyethylene and l...

Polyethylene glycols: An effective strategy for limiting liver ischemia reperfusion injury

Liver ischemia-reperfusion injury(IRI) is an inherent feature of liver surgery and liver transplantation in which damage to a hypoxic organ(ischemia) is exacerbated following the return of oxygen delivery(reperfusion). IRI is a major cause of primary nonfunction after transplantation and may lead to graft rejection, regardless of immunological considerations. The immediate response involves the disruption of cellular mitochondrial oxidative phosphorylation and the accumulation of metabolic intermediates during the ischemic period, and oxidative stress during blood flow restoration. Moreover, a complex cascade of inflammatory mediators is generated during reperfusion, contributing to the extension of the damage and finally to organ failure. A variety of pharmacological interventions(antioxidants, anticytokines, etc.) have been proposed to alleviate graft injury but their usefulness is limited by the local and specific action of the drugs and by their potential undesirable toxic effects. Polyethylene glycols(PEGs), which are non-toxic water-soluble compounds approved by the FDA, have been widely used as a vehicle or a base in food, cosmetics and pharmaceuticals, and also as adjuvants for ameliorating drug pharmacokinetics. Some PEGs are also currently used as additives in organ preservation solutions prior to transplantation in order to limit the damage associated with cold ischemia reperfusion. More recently, the administration of PEGs of different molecular weights by intravenous injection has emerged as a new therapeutic tool to protect liver grafts from IRI. In this review, we summarize the current knowledge concerning the use of PEGs as a useful target for limiting liver IRI.