Pentoxifylline reduces biochemical markers of ischemia-reperfusion induced spinal cord injury in rabbits

Pentoxifylline protects against cerebral ischaemia-reperfusion injury through ferroptosis regulation via the Nrf2/SLC7A11/GPX4 signalling pathway

OBJECTIVE

To investigate whether pentoxifylline (PTX) attenuates cerebral ischaemia-reperfusion injury (IRI) in rats by inhibiting ferroptosis and to explore the underlying molecular mechanisms.

METHODS

Cerebral IRI was induced in male Sprague-Dawley (SD) rats using middle cerebral artery occlusion (MCAO). The effects of PTX on cerebral ischaemia-reperfusion brain samples were detected through neurological deficit score, staining and electron microscopy; levels of ferroptosis biomarkers from brain samples were detected using kits. Additionally, the expression levels of nuclear factor erythroid 2-related factor 2 (Nrf2), transferrin receptor protein 1, divalent metal transporter 1, solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4) were determined by immunohistochemistry, real-time quantitative polymerase chain reaction and western blotting.

RESULTS

Pre-treatment with PTX was found to improve neurological function, evidenced by reduced neurological deficit scores, decreased infarct volume and alleviated pathological features post-MCAO. This improvement was accompanied by reduced lipid peroxidation levels and mitigated mitochondrial damage. Notably, PTX's inhibitory effect on ferroptosis was characterised by enhanced Nrf2 nuclear translocation and regulation of ferroptosis-related proteins. Moreover, inhibition of Nrf2 using ML385 (an Nrf2-specific inhibitor) reversed PTX's neuroprotective effect on MCAO-induced ferroptosis via the SLC7A11/GPX4 signalling pathway.

CONCLUSIONS

Ferroptosis is evident following cerebral ischaemia-reperfusion in rats. Pentoxifylline confers protection against IRI in rats by inhibiting ferroptosis through the Nrf2/SLC7A11/GPX4 signalling pathway.

Tolerance limit of external beam radiotherapy combined with low-dose rate brachytherapy in normal rabbit tissue

BACKGROUND

Dosage-optimized multimodal radiotherapies that are safe for head and neck cancer patients are desirable. In this study, we investigated tissue tolerance to varying doses of external beam radiotherapy (EBRT) combined with low-dose rate brachytherapy in the neck of a rabbit model.

METHODS

Twenty rabbits were used in the four test groups (five each) with iodine-125 seeds implanted in the neck treated with EBRT in four doses at 50, 40, 30 and 20 Gy each. Twelve rabbits for three control groups (four each). Three months after implantation, all rabbits were euthanized, and target tissues were collected. Analyses included seed implantation assessment, histopathological evaluation, immunohistochemistry staining, terminal deoxynucleotidyl transferase dUTP nick end labeling assay, electron microscopy and statistics with the SPSS software.

RESULTS

Five rabbits died in the four test groups, and three rabbits died in the three control groups (one per group), which showed no significant difference by survival analysis. The calculated minimum peripheral dose was 17.6 Gy, the maximum dose near the seed was 1812.5 Gy, the D90 was 34.5 Gy and the mean dose was 124.5 Gy. In all groups that received radiation, apoptosis occurred primarily in the esophageal mucosa and corresponded to the dose of radiation; a higher dose caused a greater apoptosis, with significant difference between groups (P < 0.05). Electron microscopy of carotid arteries revealed that endothelial cells were swollen and some were shed from basement membrane, but no other noticeable tissue damages.

CONCLUSIONS

Limited EBRT at maximal dose (50 Gy) combined with the brachytherapy interstitially applied to the neck was tolerated well in the rabbit model.

The effect of Iridoids effective fraction of Valeriana jatamansi Jones on movement function in rats after acute cord injury and the related mechanism

OBJECTIVES

Spinal cord injury (SCI) is a disastrous central nervous system (CNS) disorder, which was intimately associated with oxidative stress. Studies have confirmed that Iridoids Effective Fraction of Valeriana jatamansi Jones (IEFV) can scavenge reactive oxygen species. This study aimed to confirm the efficacy of IEFV in ameliorating SCI.

METHODS

For establish the SCI model, the Sprague-Dawley rats underwent a T10 laminectomy with transient violent oppression by aneurysm clip. Then, the rats received IEFV intragastrically for 8 consecutive weeks to evaluate the protective effect of IEFV on motor function, oxidative stress, inflammation and neurotrophic factors in SCI rats.

RESULTS

Basso, Beattie and Bresnahan scores, hematoxylin and eosin (H&E) staining and transmission electron microscopy experiments found IEFV protected motor function and alleviated neuron damage. Meanwhile, IEFV treatment decreased the release of malondialdehyde, interleukin-6 (IL-6), cyclooxygenase-2 and tumor necrosis factor-α. Moreover, IEFV treatment elevated the expression levels of brain-derived neurotrophic factor and nerve growth factor of SCI rats. Finally, administration of IEFV significantly inhibited the expression of p-p65 and toll-like receptor 4 (TLR4).

CONCLUSIONS

This study suggests that IEFV could attenuate the oxidative stress and inflammatory response of the spinal cord after SCI, which was associated with inhibition of the TLR4/nuclear factor-kappaB signaling pathway.

Acute spontaneous spinal cord infarction: Utilisation of hyperbaric oxygen treatment, cerebrospinal fluid drainage and pentoxifylline

INTRODUCTION

Spinal cord infarction (SCI) is a potentially devastating disorder presenting with an acute anterior spinal artery syndrome, accounting for an estimated 1% of stroke presentations. Aetiologies include aortic surgical complications, systemic hypotension, fibrocartilaginous embolism and vascular malformations. Diagnosis is clinical combined with restriction on diffusion-weighted magnetic resonance imaging (MRI). There are no treatment guidelines for non-perioperative cases although there is limited literature regarding potential therapies, including hyperbaric oxygen treatment (HBOT) and cerebrospinal fluid (CSF) drainage. We describe 13 cases of acute SCI, five receiving HBOT, and three also receiving pentoxifylline and drainage of lumbar CSF.

METHODS

Data for all patients with MRI-proven SCI at Fiona Stanley Hospital from 2014-2019 were reviewed.

RESULTS

Thirteen patients, median age 57 years (31-74), 54% female, were identified. Aetiologies: two fibrocartilaginous emboli; seven likely atherosclerotic; two thromboembolic; two cryptogenic. All presented with flaccid paraplegia except one with Brown-Sequard syndrome. Levels ranged from C4 to T11. Five patients received HBOT within a median time of 40 hours from symptom onset, with an average 15 treatments (10-20). Three of these received triple therapy (HBOT, pentoxifylline, CSF drainage) and had median Medical Research Council manual muscle testing power of 5, median modified Rankin Score (mRS) of 1 and American Spinal Injury Association (ASIA) score of D on discharge, compared with 2 power, mRS 3.5 and ASIA B in those who did not.

CONCLUSIONS

SCI can be severely disabling. Triple therapy with pentoxifylline, CSF drainage and HBOT may reduce disability and further prospective trials are required.

Ubiquitin and endogenous antioxidant enzymes participate in neuroprotection of the rabbit spinal cord after ischemia and bradykinin postconditioning

The aim of this study was to investigate neuroprotective effect of bradykinin postconditioning on the rabbit spinal cord after 20 min of ischemia and 3 days of reperfusion. Bradykinin was administered by single i.p. application at 1, 6, 12 or 24 h after ischemia. Assessment of neurological function of hind limbs (Tarlov score) was estimated. Quantitative analysis was evaluated by Fluoro Jade B method, NeuN and ubiquitin immunohistochemistry in anterior horn neurons of the spinal cord. Histomorphologically distribution of ubiquitin and endogenous antioxidant enzymes (SOD1, SOD2, catalase) immunoreaction was described. Bradykinin postconditioning showed decreased number of degenerated neurons, increased number of surviving neurons and increase in number of ubiquitin positive neurons in all bradykinin postconditioned groups versus ischemia/reperfusion group. According to our results bradykinin postconditioning applied 24 h after ischemia significantly decreased (p < 0.001) number of degenerated neurons versus ischemia/reperfusion group. The least effective time window for bradykinin postconditioning was at 12 h after ischemia. Tarlov score was significantly improved (p < 0.05) in groups with bradykinin postconditioning applied 1, 6 or 24 h after ischemia versus ischemia/reperfusion group. Tarlov score in group with bradykinin application 12 h after ischemia was significantly decreased (p < 0.05) versus sham control group. Neuronal immunoreaction of ubiquitin, SOD1, SOD2 and catalase influenced by bradykinin postconditioning was dependent on neuronal survival or degeneration. In conclusion, bradykinin postconditioning showed protective effect on neurons in anterior horns of the rabbit spinal cord and improved motor function of hind limbs.

Delayed xenon post-conditioning mitigates spinal cord ischemia/reperfusion injury in rabbits by regulating microglial activation and inflammatory factors

The neuroprotective effect against spinal cord ischemia/reperfusion injury in rats exerted by delayed xenon post-conditioning is stronger than that produced by immediate xenon post-conditioning. However, the mechanisms underlying this process remain unclear. Activated microglia are the main inflammatory cell type in the nervous system. The release of pro-inflammatory factors following microglial activation can lead to spinal cord damage, and inhibition of microglial activation can relieve spinal cord ischemia/reperfusion injury. To investigate how xenon regulates microglial activation and the release of inflammatory factors, a rabbit model of spinal cord ischemia/reperfusion injury was induced by balloon occlusion of the infrarenal aorta. After establishment of the model, two interventions were given: (1) immediate xenon post-conditioning—after reperfusion, inhalation of 50% xenon for 1 hour, 50% N₂/50%O₂ for 2 hours; (2) delayed xenon post-conditioning—after reperfusion, inhalation of 50% N₂/50%O₂ for 2 hours, 50% xenon for 1 hour. At 4, 8, 24, 48 and 72 hours after reperfusion, hindlimb locomotor function was scored using the Jacobs locomotor scale. At 72 hours after reperfusion, interleukin 6 and interleukin 10 levels in the spinal cord of each group were measured using western blot assays. Iba1 levels were determined using immunohistochemistry and a western blot assay. The number of normal neurons at the injury site was quantified using hematoxylin-eosin staining. At 72 hours after reperfusion, delayed xenon post-conditioning remarkably enhanced hindlimb motor function, increased the number of normal neurons at the injury site, decreased Iba1 levels, and inhibited interleukin-6 and interleukin-10 levels in the spinal cord. Immediate xenon post-conditioning did not noticeably affect the above-mentioned indexes. These findings indicate that delayed xenon post-conditioning after spinal cord injury improves the recovery of neurological function by reducing microglial activation and the release of interleukin-6 and interleukin-10.

Effects of N-acetylcysteine and pentoxifylline on remote lung injury in a rat model of hind-limb ischemia/reperfusion injury

OBJECTIVE

To investigate the effects of N-acetylcysteine (NAC) and pentoxifylline in a model of remote organ injury after hind-limb ischemia/reperfusion (I/R) in rats, the lungs being the remote organ system.

METHODS

Thirty-five male Wistar rats were assigned to one of five conditions (n = 7/group), as follows: sham operation (control group); hind-limb ischemia, induced by clamping the left femoral artery, for 2 h, followed by 24 h of reperfusion (I/R group); and hind-limb ischemia, as above, followed by intraperitoneal injection (prior to reperfusion) of 150 mg/kg of NAC (I/R+NAC group), 40 mg/kg of pentoxifylline (I/R+PTX group), or both (I/R+NAC+PTX group). At the end of the trial, lung tissues were removed for histological analysis and assessment of oxidative stress.

RESULTS

In comparison with the rats in the other groups, those in the I/R group showed lower superoxide dismutase activity and glutathione levels, together with higher malondialdehyde levels and lung injury scores (p < 0.05 for all). Interstitial inflammatory cell infiltration of the lungs was also markedly greater in the I/R group than in the other groups. In addition, I/R group rats showed various signs of interstitial edema and hemorrhage. In the I/R+NAC, I/R+PTX, and I/R+NAC+PTX groups, superoxide dismutase activity, glutathione levels, malondialdehyde levels, and lung injury scores were preserved (p < 0.05 for all). The differences between the administration of NAC or pentoxifylline alone and the administration of the two together were not significant for any of those parameters (p > 0.05 for all).

CONCLUSIONS

Our results suggest that NAC and pentoxifylline both protect lung tissue from the effects of skeletal muscle I/R. However, their combined use does not appear to increase the level of that protection.

Inflammatory mechanisms involved in brain injury following cardiac arrest and cardiopulmonary resuscitation

Cardiac arrest (CA) is a leading cause of fatality and long-term disability worldwide. Recent advances in cardiopulmonary resuscitation (CPR) have improved survival rates; however, the survivors are prone to severe neurological injury subsequent to successful CPR following CA. Effective therapeutic options to protect the brain from CA remain limited, due to the complexities of the injury cascades caused by global cerebral ischemia/reperfusion (I/R). Although the precise mechanisms of neurological impairment following CA-initiated I/R injury require further clarification, evidence supports that one of the key cellular pathways of cerebral injury is inflammation. The inflammatory response is orchestrated by activated glial cells in response to I/R injury. Increased release of danger-associated molecular pattern molecules and cellular dysfunction in activated microglia and astrocytes contribute to ischemia-induced cytotoxic and pro-inflammatory cytokines generation, and ultimately to delayed death of neurons. Furthermore, cytokines and adhesion molecules generated within activated microglia, as well as astrocytes, are involved in the innate immune response; modulate influx of peripheral immune and inflammatory cells into the brain, resulting in neurological injury. The present review discusses the molecular aspects of immune and inflammatory mechanisms in global cerebral I/R injury following CA and CPR, and the potential therapeutic strategies that target neuroinflammation and the innate immune system.

Response of antimicrobial peptides from porcine neutrophils to pentoxifylline and antigens from Gram negative and Gram positive bacteria

Neutrophils, the main component of the defense against invading organisms have also been implicated in tissue damage in numerous inflammatory conditions. Neutrophil products can degrade the extracellular matrix and when excessively released are thought to cause some disorders. As it is known, pentoxifylline (PTX) can suppress a range of neutrophil responses. Cathelicidins are components of the early host defenses against infection, however, in most cases cleavage with elastase is necessary to obtain active forms. Thus, the aim of our study was to assess the usage of PTX as a factor which could inhibit some neutrophil functions, and to assess if PTX can lead to the impairment of the release from these cells active cathelicidins. For these purposes we determined neutrophil activity as well as expression of cathelicidins from porcine neutrophils in cultures under the influence of PTX. PTX exerted an inhibitory effect on elastase and MPO release from neutrophils. At lower concentrations of PTX, ALP release was inhibited both in cultures stimulated with PTX+fMLP and with PTX+LPS. Inhibition of superoxide generation was insignificant, whereas a decrease of NO production was noted. The MALDI TOF analysis revealed that in all cultures stimulated with PTX+fLMP and PTX+LPS there was no inhibition of the release of cathelicidins in comparison with cultures stimulated only with fMLP and only with LPS. Our study proved that although PTX in porcine neutrophils is able to suppress many neutrophil functions, the expression of cathelicidins is maintained.

Hypoxia promotes apoptosis of neuronal cells through hypoxia-inducible factor-1α-microRNA-204-B-cell lymphoma-2 pathway

Neuronal cells are highly sensitive to hypoxia and may be subjected to apoptosis when exposed to hypoxia. Several apoptosis-related genes and miRNAs involve in hypoxia-induced apoptosis. This study aimed to examine the role of HIF1α-miR-204-BCL-2 pathway in hypoxia-induced apoptosis in neuronal cells. Annexin V/propidium iodide assay was performed to analyze cell apoptosis in AGE1.HN and PC12 cells under hypoxic or normoxic conditions. The expression of BCL-2 and miR-204 were determined by Western blot and qRT-PCR. The effects of miR-204 overexpression or knockdown on the expression of BCL-2 were evaluated by luciferase assay and Western blot under hypoxic or normoxic conditions. HIF-1α inhibitor YC-1 and siHIF-1α were employed to determine the effect of HIF-1α on the up-regulation of miR-204 and down-regulation of BCL-2 induced by hypoxia. Apoptosis assay showed the presence of apoptosis induced by hypoxia in neuronal cells. Moreover, we found that hypoxia significantly down-regulated the expression of BCL-2, and increased the mRNA level of miR-204 in neuronal cells than that in control. Bioinformatic analysis and luciferase reporter assay demonstrated that miR-204 directly targeted and regulated the expression of BCL-2. Specifically, the expression of BCL-2 was inhibited by miR-204 mimic and enhanced by miR-204 inhibitor. Furthermore, we detected that hypoxia induced cell apoptosis via HIF-1α/miR-204/BCL-2 in neuronal cells. This study demonstrated that HIF-1α-miR-204-BCL-2 pathway contributed to apoptosis of neuronal cells induced by hypoxia, which could potentially be exploited to prevent spinal cord ischemia-reperfusion injury.

The effects of quinacrine, proglumide, and pentoxifylline on seizure activity, cognitive deficit, and oxidative stress in rat lithium-pilocarpine model of status epilepticus

The present data indicate that status epilepticus (SE) induced in adult rats is associated with cognitive dysfunctions and cerebral oxidative stress (OS). This has been demonstrated using lithium-pilocarpine (Li-Pc) model of SE. OS occurring in hippocampus and striatum of mature brain following SE is apparently due to both the increased free radicals production and the limited antioxidant defense. Pronounced alterations were noticed in the enzymatic, glutathione-S transferase (GST), catalase (CAT), and superoxide dismutase (SOD), as well as in the nonenzymatic; thiobarbituric acid (TBARS) and reduced glutathione (GST), indices of OS in the hippocampus and striatum of SE induced animals. Quinacrine (Qcn), proglumide (Pgm), and pentoxifylline (Ptx) administered to animals before inducing SE, were significantly effective in ameliorating the seizure activities, cognitive dysfunctions, and cerebral OS. The findings suggest that all the drugs were effective in the order of Ptx < Pgm < Qcn indicating that these drugs are potentially antiepileptic as well as antioxidant; however, further studies are needed to establish this fact. It can be assumed that these antiepileptic substances with antioxidant properties combined with conventional therapies might provide a beneficial effect in treatment of epilepsy through ameliorating the cerebral OS.

Early Surgical Decompression Restores Neurovascular Blood Flow and Ischemic Parameters in an in Vivo Animal Model of Nerve Compression Injury

BACKGROUND

Chronic nerve compression neuropathies result in decreased blood flow at the site of compression. Surgical decompression of the nerve often has variable postoperative results. The current study examines whether the timing of surgical intervention is an important variable in reversing the compression-induced ischemia and associated changes in biochemical markers.

METHODS

An established model of chronic nerve compression injury was created in 100 C57BL/6 mice, and serial electrophysiological examinations were used to confirm the creation of a chronic nerve compression injury. Laser speckle imaging was used to measure neural blood flow. Nerves in the animals that did not undergo decompression were harvested at two, four, and six weeks after injury and analyzed for hypoxia-inducible factor 1α (HIF1α), catalase, superoxide dismutase (SOD), and matrix metalloproteinases (MMPs) 2 and 9. Surgical decompression in other animals was performed at either an early (two-week) or late (six-week) time point after injury, with specimens harvested at multiple time points after decompression. One-way analysis of variance with Bonferroni correction was performed.

RESULTS

Chronic nerve compression injury initially induced hyperemia (1.37 ± 0.50 times that in the contralateral, uninjured nerve) followed by a decline in neural blood flow by four weeks (0.66 ± 0.14, p = 0.0313). In parallel, HIF1α, catalase, and SOD were elevated early after compression, whereas extracellular matrix-altering proteins were elevated later in the disease. Although early decompression yielded a return of blood flow to a hyperemic state (1.35 ± 0.16, p = 0.0057), late decompression did not result in reversal of the abnormal neurovascular flow. With late decompression, an MMP9-mediated structural alteration of the extracellular matrix was seen, producing irreversible changes in blood flow parameters. Although nerve conduction velocity measurements returned to normal two weeks after decompression irrespective of the timing of the surgical intervention, distal latency returned to normal only after early decompression (0.97 ± 0.06 msec compared with 1.22 ± 0.06 msec for late decompression, p = 0.009).

CONCLUSIONS

Chronic nerve compression injuries decreased neurovascular flow and induced ischemia by upregulating HIF1α, catalase, and MMP9. Early surgical intervention offered better return to normal electrophysiological parameters compared with late intervention.

CLINICAL RELEVANCE

These data present a clinical correlate to the variable functional outcomes seen following surgical release of chronic nerve compression injuries and provide early support for using distal latency as a predictor of outcomes following surgical release.

Development and treatments of inflammatory cells and cytokines in spinal cord ischemia-reperfusion injury

During aortic surgery, interruption of spinal cord blood flow might cause spinal cord ischemia-reperfusion injury (IRI). The incidence of spinal cord IRI after aortic surgery is up to 28%, and patients with spinal cord IRI might suffer from postoperative paraplegia or paraparesis. Spinal cord IRI includes two phases. The immediate spinal cord injury is related to acute ischemia. And the delayed spinal cord injury involves both ischemic cellular death and reperfusion injury. Inflammation is a subsequent event of spinal cord ischemia and possibly a major contributor to spinal cord IRI. However, the development of inflammatory mediators is incompletely demonstrated. And treatments available for inflammation in spinal cord IRI are insufficient. Improved understanding about spinal cord IRI and the development of inflammatory cells and cytokines in this process will provide novel therapeutic strategies for spinal cord IRI. Inflammatory cytokines (e.g., TNF-α and IL-1) may play an important role in spinal cord IRI. For treatment of several intractable autoimmune diseases (e.g., rheumatoid arthritis), where inflammatory cytokines are involved in disease progression, anti-inflammatory cytokine antagonist is now available. Hence, there is great potential of anti-inflammatory cytokine antagonist for therapeutic use of spinal cord IRI. We here review the mediators and several possibilities of treatment in spinal cord IRI.

iNOS participates in apoptosis of spinal cord neurons via p-BAD dephosphorylation following ischemia/reperfusion (I/R) injury in rat spinal cord

The pro-apoptotic effect of nitric oxide (NO) has been reported both in vivo and in vitro. Previous studies have revealed that NO, especially which produced by inducible nitric oxide synthase (iNOS), has an important effect on apoptosis of neurons in spinal cord ischemia/reperfusion (I/R) injury. To investigate the role of iNOS in this process, a randomized, controlled study was designed using a classical rat model of ischemic spinal cord injury. Fifty-four male Sprague-Dawley rats were randomly divided into three different groups: a sham-operated group (n=6), a vehicle group (I/R, n=24), and an iNOS inhibitor (aminoguanidine: AG) group (I/R+AG, n=24). Rats were sacrificed 6, 12, 24 and 72 h after reperfusion. We examined neurological motor function evaluated by 'Tarlov's score', assessed alterations in the morphology of spinal cord neurons by transmission electron microscopy (TEM), analyzed expression of iNOS at the levels of mRNA and protein, evaluated local concentrations and cellular locations of other key regulatory proteins, and investigated protein-protein interactions. In the vehicle group, iNOS expression, dephosphorylation of p-BAD (Ser 136), disassociation of BAD from p-BAD/14-3-3 dimers, and release of cytochrome c were all increased compared with the sham group. But in the AG group, all the performances above were decreased compared with the vehicle group. Similarly, rats in the sham group got a maximum score of 5 by Tarlov's motor scores evaluation. While the scores were higher in the AG group compared to the vehicle group because iNOS was inhibited. These results indicate that the activity of iNOS plays a critical role in the apoptosis of spinal cord neurons by influencing the dephosphorylation of p-BAD (Ser 136) and the interaction between BAD and 14-3-3.

Acute effect of Ghrelin on ischemia/reperfusion injury in the rat spinal cord

Ghrelin, a 28-amino acid peptide, is mainly secreted by the stomach. Ghrelin has been shown to have neuroprotective effects. However, whether ghrelin protects the spinal cord from ischemia/reperfusion (I/R) injury is unknown. To investigate this, 60 rats were randomly divided into three different groups: the sham group (n = 20), the vehicle group (n = 20), and the Ghrelin group (100 μg/kg, n = 20). Rats were sacrificed 12, 24, 48 and 72 h after ischemia. After the evaluation of neurologic function (48 h), the spinal cords were immediately removed for the determination of myeloperoxidase (MPO) activity (12-72 h). Apoptosis was quantitatively measured using the terminal transferase UTP nick end-labeling (TUNEL) method (24 h). The expression of bax and bcl-2 were evaluated by Western blot analysis (1 h), and GHSR-1a mRNA expression was detected using reverse transcriptase polymerase chain reaction (24 h). The neurological motor function was evaluated by 'Tarlov's score'. The neurologic outcomes in the ghrelin-group were significantly better than those in the vehicle group (p < 0.05). Serum tumor necrosis factor (TNF-α) levels were assessed in the peripheral venous blood. Ghrelin decreased the serum TNF-α levels and ameliorated the down regulation of spinal cord MPO activity. The expression of ghrelin receptors (GHSR-1a) in the rat spinal cord was decreased by I/R injury and increased by ghrelin. Ghrelin reduced the TUNEL-positive rate. Greater bcl-2, HSP27, HSP70, and attenuated bax expression were observed in the ghrelin-treated rats. Our results suggest that ghrelin administration may inhibit spinal I/R injury. Moreover, the improvement of neurologic function in rats was increased after the ghrelin treatment.

Pentoxifylline and prevention of hyperoxia-induced lung -injury in neonatal rats

INTRODUCTION

Oxygen exposure plays an important role in the pathogenesis of bronchopulmonary dysplasia (BPD). The phosphodiesterase inhibitor pentoxifylline (PTX) has anti-inflammatory and antifibrotic effects in multiple organs. It was hypothesized that PTX would have a protective effect on hyperoxia-induced lung injury (HILI).

METHODS

Newborn Sprague-Dawley rats were exposed to >95% oxygen (O(2)) and injected subcutaneously with normal saline (NS) or PTX (75 mg/kg) twice a day for 9 d. NS-injected, room air-exposed pups were controls. At days 4 and 9, lung tissue was collected to assess edema, antioxidant enzyme (AOE) activities, and vascular endothelial growth factor (VEGF) expression. At day 9, pulmonary macrophage infiltration, vascularization, and alveolarization were also examined.

RESULTS

At day 9, treatment with PTX significantly increased survival from 54% to 88% during hyperoxia. Treatment with PTX significantly decreased lung edema and macrophage infiltration. PTX treatment increased lung AOE activities including those of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX). Furthermore, PTX treatment also increased the gene expression of VEGF189 and VEGF165, increased VEGF protein expression, and improved pulmonary vascularization.

DISCUSSION

These data indicate that the reduced lung edema and inflammation, increased AOE activities, and improved vascularization may be responsible for the improved survival with PTX during hyperoxia. PTX may be a potential therapy in reducing some of the features of BPD in preterm newborns.

Pretreatment with pentoxifylline and N-acetylcysteine in liver ischemia reperfusion-induced renal injury

BACKGROUND AND AIMS

Acute hepatic injury causes systematic inflammatory responses which may finally lead to functional disturbances in remote organs. In this study, the effects of an inhibitor of inflammatory cytokines (pentoxifylline, PTX) and a well-known antioxidant, N-acetylcysteine (NAC), were evaluated on renal damage and oxidative stress following liver ischemia reperfusion (IR).

METHOD

Five groups of six male rats were used. Group 1 was sham operated. In group 2, 90 min liver partial ischemia was induced by a clamp around both hepatic artery and portal vein and then followed by 4 h of reperfusion. In groups 3 and 4, PTX or NAC was injected intraperitoneally before the ischemia, while in group 5 both drugs were co-administered. The levels of alanine amino-transferase (ALT), aspartate amino-transferase (AST), blood urea nitrogen (BUN), and creatinine in serum as well as malonyldialdehyde (MDA) and glutathione (GSH) levels and morphological changes in renal tissues were assessed.

RESULTS

Significant increase in the serum levels of ALT and AST in IR group is indicative of liver functional damages. Elevated BUN and renal tissue MDA, decreased GSH levels, and morphological damages in IR group demonstrate a significant kidney injury and oxidative stress comparing to sham group. Administration of PTX alone and PTX + NAC prevented the IR-induced increase in renal MDA levels. Administration of both drugs and their co-administration prevented the reduction in renal GSH levels and morphological changes.

CONCLUSION

Pretreatment with PTX and NAC before liver IR may be useful to ameliorate renal oxidative damage by preservation of cellular GSH concentration and a reduction in MDA levels.

Neuroprotective effects of PEP-1-Cu,Zn-SOD against ischemic neuronal damage in the rabbit spinal cord

A rabbit model of spinal cord ischemia has been introduced as a good model to investigate the pathophysiology of ischemia-reperfusion (I-R)-induced paraplegia. In the present study, we observed the effects of Cu,Zn-superoxide dismutase (SOD1) against ischemic damage in the ventral horn of L(5-6) levels in the rabbit spinal cord. For this study, the expression vector PEP-1 was constructed, and this vector was fused with SOD1 to create a PEP-1-SOD1 fusion protein that easily penetrated the blood-brain barrier. Spinal cord ischemia was induced by transient occlusion of the abdominal aorta for 15 min. PEP-1-SOD1 (0.5 mg/kg) was intraperitoneally administered to rabbits 30 min before ischemic surgery. The administration of PEP-1-SOD1 significantly improved neurological scores compared to those in the PEP-1 (vehicle)-treated ischemia group. Also, in this group, the number of cresyl violet-positive cells at 72 h after I-R was much higher than that in the vehicle-treated ischemia group. Malondialdehyde levels were significantly decreased in the ischemic spinal cord of the PEP-1-SOD1-treated ischemia group compared to those in the vehicle-treated ischemia group. In contrast, the administration of PEP-1-SOD1 significantly ameliorated the ischemia-induced reduction of SOD and catalase levels in the ischemic spinal cord. These results suggest that PEP-1-SOD1 protects neurons from spinal ischemic damage by decreasing lipid peroxidation and maintaining SOD and catalase levels in the ischemic rabbit spinal cord.

The use of pentoxifylline as adjuvant therapy with praziquantel downregulates profibrogenic cytokines, collagen deposition and oxidative stress in experimental schistosomiasis mansoni

This study investigates the possible use of pentoxifylline (PTX), with antifibrotic and anti-inflammatory properties, as adjuvant in treatment of schistosomal liver fibrosis through determination of some profibrogenic cytokines, oxidative stress and collagen deposition. Animals were classified into seven groups: normal control (i), Schistosoma mansoni-infected untreated (ii), infected treated with praziquantel (PZQ) curative, 1000mg/kg (iii) or sub curative, 200mg/kg dose (iv), infected treated with PTX alone (10mg/kg/day; 5days/wk) for 8weeks starting from the 2nd to the 10th week post infection (v), or in addition to curative (vi) or sub curative dose of PZQ (vii). Serum transforming growth factor-β1 (TGF-β1), tumor necrosis factor-α (TNF-α), matrix metalloproteinases-2 (MMP-2) and hepatic hydroxyproline (Hyp) content, glutathione related antioxidant enzymes and malondialdehyde (MDA) were determined. Results showed that S. mansoni infection produced remarkable elevations in the serum levels of TGF-β1, TNF-α, MMP-2 and the hepatic contents of Hyp, glutathione reductase (GR), MDA with significant reduction in reduced glutathione (GSH), glutathione peroxidase (GPx), glutathione-S-transferase (GST) and superoxide dismutase (SOD) when compared with their corresponding normal controls. Treatment of infected mice with PTX in addition to PZQ curative rather than its sub curative dose produced the best results evidenced by complete normalization in the previously mentioned serum and hepatic parameters.

CONCLUSION

PTX could attenuate liver fibrosis in early stages of S. mansoni infection through downregulation of profibrogenic cytokines, oxidative stress and collagen deposition.

Hydroxysafflor Yellow A protects spinal cords from ischemia/reperfusion injury in rabbits

Background

Hydroxysafflor Yellow A (HSYA), which is one of the most important active ingredients of the Chinese herb Carthamus tinctorius L, is widely used in the treatment of cerebrovascular and cardiovascular diseases. However, the potential protective effect of HSYA in spinal cord ischemia/reperfusion (I/R) injury is still unknown.

Methods

Thirty-nine rabbits were randomly divided into three groups: sham group, I/R group and HSYA group. All animals were sacrificed after neurological evaluation with modified Tarlov criteria at the 48th hour after reperfusion, and the spinal cord segments (L4-6) were harvested for histopathological examination, biochemical analysis and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) staining.

Results

Neurological outcomes in HSYA group were slightly improved compared with those in I/R group. Histopathological analysis revealed that HSYA treatment attenuated I/R induced necrosis in spinal cords. Similarly, alleviated oxidative stress was indicated by decreased malondialdehyde (MDA) level and increased superoxide dismutase (SOD) activity after HSYA treatment. Moreover, as seen from TUNEL results, HSYA also protected neurons from I/R-induced apoptosis in rabbits.

Conclusions

These findings suggest that HSYA may protect spinal cords from I/R injury by alleviating oxidative stress and reducing neuronal apoptosis in rabbits.

Amyotrophic lateral sclerosis: a consensus viewpoint on designing and implementing a clinical trial

In November 2002, an advisory board meeting was convened by Novartis Pharma to provide recommendations and rationale for clinical trials designed to evaluate new treatments, such as TCH346, for amyotrophic lateral sclerosis (ALS). In terms of selecting appropriate outcome measures, the panel recommended the use of the ALS Functional Rating Scale (ALSFRS-R) to measure primary endpoints. A review of other key issues in this area including regional variations in the epidemiology, diagnosis and management of ALS, defining patient populations and doses of trial medication, and accommodating the likelihood of co-medication with pre-existing treatment in trial design, are discussed.

The Neuroprotective and Anti-inflammatory Effects of Diltiazem in Spinal Cord Ischaemia–Reperfusion Injury

The protective effects of diltiazem were examined in a rabbit model of spinal cord ischaemia–reperfusion induced by infrarenal aortic occlusion for 30 min. In the diltiazem group ( n = 6), an intravenous infusion (2 μg/kg per min) was started 10 min before ischaemia induction; normal saline solution was infused in the control group ( n = 6). Neurological function was assessed using modified Tarlov criteria 24 h after surgery. Plasma samples were analysed for interleukin (IL)-6 and IL-10. Spinal tissue was analysed for malondialdehyde, nitric oxide and reduced glutathione activities. Tarlov scores of the diltiazem-treated rabbits indicated significantly improved hind-limb motor function compared with the control group. The diltiazem group also had better quantitative and qualitative histopathological findings. Diltiazem infusion significantly reduced IL-6 levels 3 and 24 h after reperfusion compared with the control group. The mean IL-10 level in the diltiazem group was significantly higher than in the control group 24 h after reperfusion. It is concluded that diltiazem has cytoprotective and anti-inflammatory properties, leading to reduced spinal cord injury.

Pentoxifylline ameliorates lithium-pilocarpine induced status epilepticus in young rats

The neuroprotective effects of pentoxifylline (PTX) against lithium-pilocarpine (Li-Pc)-induced status epilepticus (SE) in young rats are described. Animals treated with PTX (0, 20, 40, and 60 mg/kg) before induction of SE were examined for latency to and frequency of SE, behavioral changes, oxidative stress, neurochemical alterations in the hippocampus and striatum, and histological abnormalities in the hippocampus. Treatment with PTX significantly ameliorated the frequency and severity of epileptic seizures in a dose-dependent manner. Our behavioral studies using the elevated plus-maze, rotarod, and water maze tests suggested a significant reduction in anxiety, enhanced motor performance, and improved learning and memory in PTX-treated rats. Li-Pc-induced neuronal cell loss and sprouting of mossy fibers in the hippocampus were also attenuated by PTX. The neuroprotective activity of PTX was accompanied by reduction in oxidative stress and reversal of SE-induced depletion of dopamine and 5-hydroxytryptamine in hippocampus and striatum. The results of this study provide a good rationale to explore the prophylactic/therapeutic potential of PTX in SE.

Post-ischemic treatment of pentoxifyline reduces cortical not striatal infarct volume in transient model of focal cerebral ischemia in rat

Previous studies reported that pentoxifylline (PTX) have a neuroprotective effect in the brain trauma and the global cerebral ischemia in the experimental models. However, the effect of PTX in transient model of focal cerebral ischemia has not been investigated yet. Therefore, this study was designed to investigate the effect of post-ischemic treatment of PTX on ischemic injuries in focal cerebral ischemic. Male Wistar rats (n=32) were assigned to control or PTX- (60 mg/kg i.p.) treated groups. PTX at dose 60 mg/kg i.p. administered at the beginning, or 1, or 3 h after ischemia. Focal cerebral ischemia was induced by middle cerebral artery occlusion, followed by 24-h reperfusion. At the end of 24 h ischemia, neurological dysfunction score was tested and infarct volumes were determined using triphenyltetrazolium chloride staining. Administration of PTX (60 mg/kg) at the beginning of ischemia, or 1, or 3 h after ischemia significantly reduces cortical infarct volumes by 43%, 40% and 41%, respectively. However, PTX did not significantly affect striatal infarct volumes and neurological dysfunction. The findings of the present study indicate that administration of PTX at least 3 h post-transient focal stroke reduces cortical brain ischemic damage in the rat model of transient focal cerebral ischemia.

Anti-apoptotic and neuroprotective effects of Tetramethylpyrazine following spinal cord ischemia in rabbits

Background

Tetramethylpyrazine (TMP) is one of the most important active ingredients of a Chinese herb Ligusticum wallichii Franchat, which is widely used in many ischemia disorders treatments. However, the exact mechanism by which TMP protects the spinal cord ischemia/reperfusion (I/R) injury is still unknown. For this purpose, rabbits were randomly divided into sham group, control group and TMP group. After the evaluation of neurologic function, the spinal cords were immediately removed for biochemical and histopathological analysis. Apoptosis was measured quantitatively by the terminal transferase UTP nick end-labeling (TUNEL) method and confirmed by electron microscopic examination, the expression of Bax and Bcl-2 was immunohistochemically evaluated and quantified by Western blot analysis.

Results

Neurologic outcomes in the TMP-group were significantly better than those in the control group (P < 0.05). TMP decreased spinal cord malondialdehyde (MDA) levels and ameliorated the down regulation of spinal cord superoxide dismutase (SOD) activity. TMP significantly reduced the loss of motoneurons and TUNEL-positive rate. Greater Bcl-2 and attenuated Bax expression was found in the TMP treating rabbits.

Conclusion

These findings suggest that TMP has protective effects against spinal cord I/R injury by reducing apoptosis through regulating Bcl-2 and Bax expression.

Assessment of disease progression in motor neuron disease

Motor neuron disease (MND) is characterised by progressive deterioration of the corticospinal tract, brainstem, and anterior horn cells of the spinal cord. There is no pathognomonic test for the diagnosis of MND, and physicians rely on clinical criteria-upper and lower motor neuron signs-for diagnosis. The presentations, clinical phenotypes, and outcomes of MND are diverse and have not been combined into a marker of disease progression. No single algorithm combines the findings of functional assessments and rating scales, such as those that assess quality of life, with biological markers of disease activity and findings from imaging and neurophysiological assessments. Here, we critically appraise developments in each of these areas and discuss the potential of such measures to be included in the future assessment of disease progression in patients with MND.

Pentoxifylline Prevents Spontaneous Brain Ischemia in Stroke-Prone Rats

Anti-inflammatory properties of pentoxifylline (PTX) have recently been described. Spontaneously hypertensive stroke-prone rats (SHRSP) constitute an animal model that develops an inflammatory condition that precedes the appearance of brain abnormalities. The aim of the present investigation was to assess: 1) the efficacy of PTX treatment in protecting the neural system in SHRSP, and 2) how its anti-inflammatory properties might be involved in this effect. Male SHRSP fed with a permissive diet received no drug or PTX (100 or 200 mg/kg/day). Brain abnormalities detected by magnetic resonance imaging developed spontaneously in control rats after 42 +/- 3 days, whereas in rats treated with 100 mg/kg/day PTX, abnormalities developed in only 80% of the animals and only after 70 to 80 days. Treatment with a higher dose of PTX (200 mg/kg/day) completely protected the brain from abnormal development. The drug treatment prevented the accumulation of macrophages or CD4+ positive cells, the activation of glia in brain tissues, and the appearance of inflammatory proteins and thiobarbituric acid-reactive substances in body fluids. PTX treatment did induce a greater increase of serum tumor necrosis factor-alpha (TNF-alpha), but not of interleukin (IL)-1beta and IL-6 induced by in vivo administration of lipopolysaccharide (LPS), which suggests a protective role for TNF-alpha. PTX also exerted protective effects when it was administered after the first occurrence of proteinuria (>40 mg/day). These data indicate that PTX treatment dose-dependently prevents the occurrence of spontaneous brain damage by reducing inflammatory events. We also hypothesize that the increase of TNF-alpha by PTX treatment represents a protective mechanism in SHRSP.