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

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.

PHLDA1 knockdown alleviates mitochondrial dysfunction and endoplasmic reticulum stress-induced neuronal apoptosis via activating PPARγ in cerebral ischemia-reperfusion injury

Mitochondrial dysfunction and endoplasmic reticulum (ER) stress occur in ischemic stroke. The disruption of these two organelles can directly lead to cell death through various signaling pathways. Thus, investigation of the associated molecular mechanisms in cerebral ischemia is a prerequisite for stroke treatment. Pleckstrin homology-like domain family A member 1 (PHLDA1) is a multifunctional protein that can modulate mitochondrial function and ER stress in cardiomyocyte and cancer cells. This work studied the role of PHLDA1 in cerebral ischemic/reperfusion (I/R) injury and explored the underlying mechanisms associated with mitochondrial functions and ER stress. Middle cerebral artery occlusion/reperfusion (MCAO/R)-treated mice and oxygen-glucose deprivation/reoxygenation (OGD/R)-stimulated neurons were used as I/R models in vivo and in vitro, respectively. PHLDA1 was upregulated in ischemic penumbra of MCAO/R-induced mice and OGD/R-exposed neurons. In vitro, PHLDA1 knockdown protected neurons from OGD/R-induced apoptosis. In vivo, PHLDA1 silencing facilitated functional recovery and reduced cerebral infarct volume. Mechanistically, PHLDA1 knockdown promoted PPARγ nuclear translocation, which may mediate the effects on reversion of mitochondrial functions and alleviation of ER stress. In summary, PHLDA1 knockdown alleviates neuronal ischemic injuries in mice. PPARγ activation and mitochondrial dysfunction and endoplasmic reticulum stress attenuation are involved in the underlying mechanisms.

Pentoxifylline alleviates ischemic white matter injury through up-regulating Mertk-mediated myelin clearance

BACKGROUND

Vascular dementia (VAD) is the second most common type of dementia lacking effective treatments. Pentoxifylline (PTX), a nonselective phosphodiesterase inhibitor, displays protective effects in multiple cerebral diseases. In this study, we aimed to investigate the therapeutic effects and potential mechanisms of PTX in VAD.

METHODS

Bilateral common carotid artery stenosis (BCAS) mouse model was established to mimic VAD. Mouse behavior was tested by open field test, novel object recognition test, Y-maze and Morris water maze (MWM) tests. Histological staining, magnetic resonance imaging (MRI) and electron microscopy were used to define white matter integrity. The impact of PTX on microglia phagocytosis, peroxisome proliferator-activated receptors-γ (PPAR-γ) activation and Mer receptor tyrosine kinase (Mertk) expression was assessed by immunofluorescence, western blotting and flow cytometry with the application of microglia-specific Mertk knockout mice, Mertk inhibitor and PPAR-γ inhibitor.

RESULTS

Here, we found that PTX treatment alleviated cognitive impairment in novel object recognition test, Y-maze and Morris water maze tests. Furthermore, PTX alleviated white matter injury in corpus callosum (CC) and internal capsule (IC) areas as shown by histological staining and MRI analysis. PTX-treatment group presented thicker myelin sheath than vehicle group by electron microscopy. Mechanistically, PTX facilitated microglial phagocytosis of myelin debris by up-regulating the expression of Mertk in BCAS model and primary cultured microglia. Importantly, microglia-specific Mertk knockout blocked the therapeutic effects of PTX in BCAS model. Moreover, Mertk expression was regulated by the nuclear translocation of PPAR-γ. Through modulating PPAR-γ, PTX enhanced Mertk expression.

CONCLUSIONS

Collectively, our results demonstrated that PTX showed therapeutic potentials in VAD and alleviated ischemic white matter injury via modulating Mertk-mediated myelin clearance in microglia.

Inhibition of miR-19a-3p decreases cerebral ischemia/reperfusion injury by targeting IGFBP3 in vivo and in vitro

BACKGROUND

Inflammation and apoptosis are considered to be two main factors affecting ischemic brain injury and the subsequent reperfusion damage. MiR-19a-3p has been reported to be a possible novel biomarker in ischemic stroke. However, the function and molecular mechanisms of miR-19a-3p remain unclear in cerebral ischemia/reperfusion (I/R) injury.

METHODS

The I/R injury model was established in vivo by middle cerebral artery occlusion/reperfusion (MCAO/R) in rats and in vitro by oxygen-glucose deprivation and reperfusion (OGD/R) induced SH-SY5Y cells. The expression of miR-19a-3p was determined by reverse transcription quantitative PCR. The infarction volumes, Neurological deficit scores, apoptosis, cell viability, pro-inflammatory cytokines and apoptosis were evaluated using Longa score, Bederson score, TTC, TUNEL staining, CCK-8, ELISA, flow cytometry assays. Luciferase reporter assay was utilized to validate the target gene of miR-19a-3p.

RESULTS

We first found miR-19a-3p was significantly up-regulated in rat I/R brain tissues and OGD/R induced SH-SY5Y cells. Using the in vivo and in vitro I/R injury model, we further demonstrated that miR-19a-3p inhibitor exerted protective role against injury to cerebral I/R, which was reflected by reduced infarct volume, improved neurological outcomes, increased cell viability, inhibited inflammation and apoptosis. Mechanistically, miR-19a-3p binds to 3'UTR region of IGFBP3 mRNA. Inhibition of miR-19a-3p caused the increased expression of IGFBP3 in OGD/R induced SH-SY5Y cells. Furthermore, we showed that IGFBP3 overexpression imitated, while knockdown reversed the protective effects of miR-19a-3p inhibitor against OGD/R-induced injury.

CONCLUSIONS

In summary, our findings showed miR-19a-3p regulated I/R-induced inflammation and apoptosis through targeting IGFBP3, which might provide a potential therapeutic target for cerebral I/R injury.

Aralia taibaiensis Protects against I/R-Induced Brain Cell Injury through the Akt/SIRT1/FOXO3a Pathway

BACKGROUND

Saponin from Aralia taibaiensis (sAT) showed excellent antioxidative effects in several models; however, its effects on brain cells were unknown to us. The present study was designed to evaluate the protective effects of sAT on ischemia/reperfusion- (I/R-) induced injury and clarify its mechanisms.

METHODS

In vitro, HT22 cells were pretreated with sAT and then subjected to I/R. Apoptosis rate, mitochondrial function, and antioxidant proteins were measured. To clarify the mechanisms, siRNA were used. In vivo, sAT was pretreated through intragastric administration for 7 days and the I/R model was induced. The neurobehavioral scores, infarction volumes, and some cytokines in the brain were measured. Protein levels were investigated by Western blotting.

RESULTS

The results showed that sAT treatment significantly protected cells from I/R-induced cell apoptosis and mitochondrial dysfunction. The antioxidant protein levels were increased in a dose-dependent manner. Further study revealed that sAT induced the deacetylation and phosphorylation of PGC-1α and FOXO3a. sAT treatment also induced the phosphorylation levels of Akt and the expression levels of SIRT1. Using the specific targeted siRNA transfection, the interplay relationship between Akt, SIRT1, PGC-1α, and FOXO3a was verified. Furthermore, the same protective effects were also observed in rats subjected to I/R.

CONCLUSION

sAT protected brain cells from I/R-induced mitochondrial oxidative stress and dysfunction through regulating the Akt/SIRT1/FOXO3a/PGC-1α pathway.

Neuroprotective effect of Apelin 13 on ischemic stroke by activating AMPK/GSK-3β/Nrf2 signaling

Background

Previous studies had showed that Apelin 13 could protect against apoptosis induced by ischemic/reperfusion (I/R). However, the mechanisms whereby Apelin 13 protected brain I/R remained to be elucidated. The present study was designed to determine whether Apelin 13 provided protection through AMPK/GSK-3β/Nrf2 pathway.

Methods

In vivo, the I/R model was induced and Apelin 13 was given intracerebroventricularly 15 min before reperfusion. The neurobehavioral scores, infarction volumes, and some cytokines in the brain were measured. For in vitro study, PC12 cells were used. To clarify the mechanisms, proteases inhibitors or siRNA were used. Protein levels were investigated by western blotting.

Results

The results showed that Apelin 13 treatment significantly reduced infarct size, improved neurological outcomes, decreased brain edema, and inhibited cell apoptosis, oxidative stress, and neuroinflammation after I/R. Apelin 13 significantly increased the expression of Nrf2 and the phosphorylation levels of AMPK and GSK-3β. Furthermore, in cultured PC12 cells, the same protective effects were also observed. Silencing Nrf2 gene with its siRNA abolished the Apelin 13’s prevention of I/R-induced PC12 cell injury, oxidative stress, and inflammation. Inhibition of AMPK by its siRNA decreased the level of Apelin 13-induced Nrf2 expression and diminished the protective effects of Apelin 13. The interplay relationship between GSK-3β and Nrf2 was also verified with relative overexpression. Using selective inhibitors, we further identified the upstream of AMPK/GSK-3β/Nrf2 is AR/Gα/PLC/IP3/CaMKK.

Conclusions

In conclusion, the previous results showed that Apelin 13 protected against I/R-induced ROS-mediated inflammation and oxidative stress through activating the AMPK/GSK-3β pathway by AR/Gα/PLC/IP3/CaMKK signaling, and further upregulated the expression of Nrf2-regulated antioxidant enzymes.

High-throughput sequencing analysis of differentially expressed miRNAs and target genes in ischemia/reperfusion injury and apelin-13 neuroprotection

miRNAs regulate a variety of biological processes through pairing-based regulation of gene expression at the 3′ end of the noncoding region of the target miRNA. miRNAs were found to be abnormally expressed in ischemia/reperfusion injury models. High-throughput sequencing is a recently developed method for sequencing miRNAs and has been widely used in the analysis of miRNAs. In this study, ischemia/reperfusion injury models were intracerebroventricularly injected with 50 μg/kg apelin-13. High-throughput sequencing showed that 357 known miRNAs were differentially expressed among rat models, among which 78 changed to > 2-fold or < 0.5-fold. Quantitative real-time polymerase chain reaction was selected to confirm the expression levels of four miRNAs that were differentially expressed, the results of which were consistent with the results of high-throughput sequencing. Gene Ontology analysis revealed that the predicted targets of the different miRNAs are particularly associated with cellular process, metabolic process, single-organism process, cell, and binding. Kyoto Encyclopedia of Gene and Genome analysis showed that the target genes are involved in metabolic pathways, mitogen-activated protein kinase signaling pathway, calcium signaling pathway, and nuclear factor-κB signaling pathway. Our findings suggest that differentially expressed miRNAs and their target genes play an important role in ischemia/reperfusion injury and neuroprotection by apelin-13.

The Effects of Pentoxifylline on Serum Levels of Interleukin 10 and Interferon Gamma and Memory Function in Lipopolysaccharide-induced Inflammation in Rats

BACKGROUND

Studies have shown that pentoxifylline (PTX) in addition to protective effects on blood vessels probably has positive influence against the brain inflammation. Therefore, the aim of this study was to evaluate the effects of PTX on serum levels of interleukin 10 (IL-10) and interferon gamma (IFN-γ) and passive avoidance learning in lipopolysaccharide (LPS)-induced inflammation in rats.

MATERIALS AND METHODS

Inflammation was induced by intraperitoneal (i.p.) injection of LPS (0.5 and 5 mg/kg) in male Wistar rats. After a week, PTX (25 mg/kg; i.p.) was injected for 14 days. Passive avoidance learning test was used for evaluation of learning and memory. Serum levels of cytokines were measured by enzyme-linked immunosorbent assay.

RESULTS

The behavioral results did not show any significant effect of LPS and PTX on learning and memory. Both doses of LPS (0.5 and 5 mg/kg) decreased IL-10 significantly (P < 0.05). PTX prevented this reduction just in the LPS 0.5 mg/kg + PTX 25 mg/kg group. Serum level of IFN-γ was increased only in the LPS 0.5 mg/kg + PTX 25 mg/kg group comparing to the LPS 0.5 mg/kg group (P < 0.05).

CONCLUSIONS

The results showed that LPS-induced inflammation decreased the serum levels of IL-10. PTX could prevent these decreases only in mild inflammation. Both PTX and LPS-induced inflammation had no significant effects on learning and memory; therefore, their effects on CNS require further study.

Pentoxifylline Alleviates Early Brain Injury After Experimental Subarachnoid Hemorrhage in Rats: Possibly via Inhibiting TLR 4/NF-κB Signaling Pathway

Early brain injury (EBI) after subarachnoid hemorrhage (SAH) generally causes significant and lasting damage. Pentoxifylline (PTX), a nonselective phosphodiesterase inhibitor, has shown anti-inflammatory and neuroprotective properties in several brain injury models, but the role of PTX with respect to EBI following SAH remains uncertain. The purpose of this study was to investigate the effects of PTX on EBI after SAH in rats. Adult male Sprauge-Dawley rats were randomly assigned to the sham and SAH groups. PTX (30 or 60 mg/kg) or an equal volume of the administration vehicle (normal saline) was administrated at 30 min intervals following SAH. Neurological scores, brain edema, and neural cell apoptosis were evaluated. In order to explore other mechanisms, changes in the toll-like receptor 4 (TLR4) and the nuclear factor-κB (NF-κB) signaling pathway, in terms of the levels of apoptosis-associated proteins, were also investigated. We found that administration of PTX (60 mg/kg) notably improved neurological function and decreased brain edema at both 24 and 72 h following SAH. Treatment with PTX (60 mg/kg) significantly inhibited the protein expressions of TLR4, NF-κB, MyD88 and the downstream pro-inflammatory cytokines, such as the tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β). PTX also significantly reduced neural cell death and BBB permeability. Our observations may be the first time that PTX has been shown to play a neuroprotective role in EBI after SAH, potentially by suppressing the TLR4/NF-κB inflammation-related pathway in the rat brain.

Pentoxifylline Alleviates Early Brain Injury in a Rat Model of Subarachnoid Hemorrhage

BACKGROUND

Subarachnoid hemorrhage (SAH) is a severe cerebrovascular disease frequently caused by ruptured aneurysms. Early brain injury (EBI) is the primary cause of morbidity and mortality in patients diagnosed with SAH and is associated with increased intracranial pressure, decreased cerebral blood flow and cerebral ischemia. Pentoxifylline (PTX) is a methylxanthine derivative clinically proven to improve perfusion in the peripheral microcirculation and has been shown to have neuroprotective effects in brain trauma and global cerebral ischemia in experimental animal models. This study aimed to determine the effect of PTX in experimental SAH, which has not been investigated yet.

METHODS

An experimental SAH model was induced in male Wistar rats by autologous blood injection into the prechiasmatic cistern, and PTX was injected intraperitoneally immediately after SAH. The effects of PTX were evaluated 24 h after SAH via assessing the cerebral ultrastructure via transmission electron microscopy (TEM). Brain edema, blood-brain barrier (BBB) permeability, red blood cell deformability, tumor necrosis factor-alpha (TNF-alpha), nitrite-nitrate levels and apoptotic neuron death were also determined 24 h after SAH. The BBB permeability was measured by Evans blue (EB) extravasation, erythrocyte deformability was determined by filtration technique, and TNF-alpha and reactive nitrogen metobolites were analyzed in brain tissue by ELISA and spectral analysis, respectively. Apoptotic neurons were determined in brain sections by cleaved caspase-3 immunohistochemical analysis, and expression intensity was quantified using image J software.

RESULTS

Cerebral ultrastructure in SAH group animals revealed intense perivascular edema and distortion in the astrocyte foot processes. PTX treatment attenuated structural deterioration due to SAH. Brain water content, BBB permeability, TNF-alpha, nitrite-nitrate levels and apoptotic neuronal death were significantly increased 24 h after SAH and were significantly alleviated by PTX treatment. There was no significant change in red cell deformability after SAH.

CONCLUSIONS

Our results show that PTX reduces brain edema, BBB permeability, TNF-alpha expression, reactive nitrogen metobolites and apopotosis in experimental SAH. Based on our findings we suggest that PTX exerts neuroprotection against SAH-induced EBI, which might be associated with the inhibition of inflammation and apoptotic neuronal cell death.

Pentoxifylline for vascular health: a brief review of the literature

Pentoxifylline is a methylxanthine derivative that has been used for several decades in the symptomatic management of intermittent claudication. For reasons that remain fairly obscure, this drug benefits blood rheology in a number of complementary ways: decreasing blood and plasma viscosity, lowering plasma fibrinogen while promoting fibrinolysis, and improving blood filterability by enhancing erythrocyte distensibility and lessening neutrophil activation. Anti-inflammatory effects on neutrophils and macrophage/monocytes—some of them attributable to pentoxifylline metabolites—appear to play a mediating role in this regard. Although clinical trials with pentoxifylline have often been too small in size to reach statistically significant findings regarding impacts on hard end points, a review of the existing literature suggests that pentoxifylline may have potential for slowing the progression of atherosclerosis, stabilising plaque, reducing risk for vascular events, improving the outcome of vascular events, dampening the systemic inflammatory response following cardiopulmonary bypass, providing symptomatic benefit in angina and intermittent claudication, enhancing cerebral blood flow in patients with cerebrovascular disease while slowing progression of vascular dementia, improving prognosis in congestive heart failure, and aiding diabetes control. This safe and usually well-tolerated drug works in ways quite distinct from other drugs more commonly used for cardiovascular protection, and hence may confer complementary benefit when used in conjunction with them. Major clinical trials of adequate statistical power are now needed to confirm the scope of benefits that pentoxifylline can confer; studies evaluating hard end points in acute coronary syndrome, stroke/transient ischaemic attack and systolic heart failure might be particularly valuable.

Central nervous system circuits modified in heart failure: pathophysiology and therapeutic implications

The pathophysiology of heart failure (HF) is characterized by an abnormal activation of neurohumoral systems, including the sympathetic nervous and the renin-angiotensin-aldosterone systems, which have long-term deleterious effects on the disease progression. Perpetuation of this neurohumoral activation is partially dependent of central nervous system (CNS) pathways, mainly involving the paraventricular nucleus of the hypothalamus and some regions of the brainstem. Modifications in these integrative CNS circuits result in the attenuation of sympathoinhibitory and exacerbation of sympathoexcitatory pathways. In addition to the regulation of sympathetic outflow, these central pathways coordinate a complex network of agents with an established pathophysiological relevance in HF such as angiotensin, aldosterone, and proinflammatory cytokines. Central pathways could be potential targets in HF therapy since the current mainstay of HF pharmacotherapy aims primarily at antagonizing the peripheral mechanisms. Thus, in the present review, we describe the role of CNS pathways in HF pathophysiology and as potential novel therapeutic targets.

Pentoxifylline therapy attenuates intestinal injury in rat pups with hypoxic ischemic encephalopathy

AIM

The aim of this study was to evaluate the effects of post-ischemic pentoxifylline (PTX) therapy on the gut injury in neonatal rat model of hypoxic ischemic encephalopathy (HIE).

METHODS

Seven-day-old Wistar rat pups (n = 24) of either sex, delivered spontaneously, were used in this experimental study. Seven-day-old rat pups were randomly divided into three groups. Control group (n = 8): after median neck incision was made, neither ligation nor hypoxia was performed. Hypoxia group (n = 8): 0.5 ml of saline was injected intraperitoneally immediately after hypoxia. Pentoxifylline + Hypoxia group (n = 8): the rat pups were administered intraperitoneally 60 mg/kg of PTX immediately after hypoxia. Eight rats from all groups were sacrificed 24 h after drug administration. The ischemic injury was scored at least six sections at three different levels using histopathologic injury scores (HIS).

RESULTS

Induction of hypoxia/reoxygenation (H/R) increased mean HIS levels significantly at 24 h in the intestinal tissue samples in the hypoxia group as compared with the control group. Induction of H/R decreased means HIS levels significantly at 24 h in the intestinal tissue samples in the PTX + hypoxia group as compared with the hypoxia group.

CONCLUSION

In this experimental study, PTX significantly attenuated H/R-induced intestinal injury in neonatal rat model of HIE. These findings indicate that PTX can reduce the intestinal H/R injury.

Identification of conserved and novel microRNAs in cerebral ischemia-reperfusion injury of rat using deep sequencing

MicroRNAs are a class of noncoding small RNAs that regulate gene expression by inhibiting target genes at post-transcriptional levels. MicroRNAs have been highlighted in many organs and tissues, including the brain. To identify special microRNAs involved in ischemia-reperfusion injury, we performed a comprehensive small RNA profiling in rat model and the control using Illumina high-throughput sequencing. A total of 9,444,562 and 10,290,391 clean reads were sequenced from two small RNA libraries constructed, respectively. Three hundred fifty-eight known microRNAs were identified, in which 78 microRNAs exhibited significantly differential expression between model and control. In addition, 62 and 68 novel miRNAs were found in model and control, respectively. Comparative analysis showed that 24 novel microRNAs were differentially expressed with greater than six-fold change. The GO annotation suggested that predicted targets of microRNAs were enriched into the category of metabolic process, cell part, cell-extracellular communications, and so on. KEGG pathway analysis suggested that these genes were involved in many important pathways, mainly including signaling transduction, MAPK signaling pathway, NF-κB signaling pathway, and neurotrophin signaling pathway. Our findings provided a deeper understanding to the regulatory mechanism of microRNAs underlying cerebral ischemia, therefore benefitting the improvement of the protection and treatment strategies of this disease.

The effects of intraperitoneal pentoxifylline treatment in rat pups with hypoxic-ischemic encephalopathy

BACKGROUND

The aim of this study was to evaluate the effects of postischemic treatment with pentoxifylline on the cytokine gene expressions and neuronal apoptosis in neonatal rat model of hypoxic-ischemic encephalopathy.

METHODS

Seven-day-old Wistar rat pups (n = 40) of either sex, delivered spontaneously, were used in this experimental study. Control group (n = 8): after median neck incision was made, neither ligation nor hypoxia was performed, ischemia group (n = 16): 0.5 mL of saline was injected intraperitoneally immediately after hypoxia. Pentoxifylline and ischemia groups (n = 16): the rat pups were administered intraperitoneally 60 mg/kg of pentoxifylline immediately after hypoxia. Eight rats from ischemia and pentoxifylline + ischemia groups were sacrificed 4 and 24 hours after drug administration. Control group mice were decapitated 4 hours after hypoxia. Caspase-3 activity, interleukin-1β, and tumor necrosis factor-α messenger RNA expression levels were studied in the left half of the brain.

RESULTS

Induction of cerebral ischemia increased tumor necrosis factor-α and interleukin-1β messenger RNA expression levels significantly at 4 hours and 24 hours following ischemia in the left ischemic hemispheres in the ischemia group as compared with the control group. Systemic administration of pentoxifylline immediately after hypoxic-ischemic encephalopathy significantly reduced the tumor necrosis factor-α and interleukin-1β messenger RNA expression levels in ischemic tissue as compared with the ischemia group. Caspase-3 activities in the left half of the brains of ischemia group were found to be increased significantly as compared with control group. Caspase-3 activities in the brains of pentoxifylline + ischemia groups were significantly lower than in that of ischemia group.

CONCLUSIONS

Based on the significantly lower interleukin-1β and tumor necrosis factor-α gene expression measured after 4 and 24 hours and significantly reduced caspase-3 activity measured colorimetrically in the animals treated with pentoxifylline, our findings suggest that pentoxifylline may reduce brain damage due to hypoxic-ischemic injury.

Protective effects of pentoxifylline on lipopolysaccharide-induced white matter injury in a rat model of periventricular leukomalasia

OBJECTIVE

To investigate the potential neuroprotective effect of maternal pentoxifylline (PNTX) treatment in endotoxin-induced periventricular leukomalasia (PVL) in the developing rat brain.

METHOD

Intraperitoneal injection of lipopolysaccharide was administered on two of three Wistar pregnant rats to establish PVL. To obtain PNTX-treated group, one of the two dams were injected with PNTX. The control group was treated with saline. Rat pups were grouped as control, maternal LPS-treated group and PNTX + LPS-treated group. At 7th postnatal days, apoptosis and hypomyelination were evaluated. Apoptosis was evaluated by caspase-3 and terminal deoxynucleotidyl transferase [TdT] dUTP nick endlabelling reaction (TUNEL) immunostaining. To assess hypomyelination, myelin basic protein (MBP) staining, as a marker of myelination, was evaluated.

RESULTS

MBP staining was significantly less and weaker in the brains of the LPS-treated group as compared with the PNTX-treated group. PNTX treatment significantly reduced the number of apoptotic cells in the periventricular WM shown on Tunel and caspase-3.

CONCLUSIONS

Presented study is first indicated that PNTX may provide protection against an LPS-induced inflammatory response and WMI in the developing rat brain. Our results also suggest that PNTX treatment in pregnant women with maternal or placental infection may minimize the risk of PVL and cerebral palsy.

Pentoxifylline attenuates TNF-α protein levels and brain edema following temporary focal cerebral ischemia in rats

Cerebral edema is the most common cause of neurological deterioration and mortality during acute ischemic stroke. Despite the clinical importance of cerebral ischemia, the underlying mechanisms remain poorly understood. Recent studies suggest a role for TNF-α in the brain edema formation. To further investigate whether TNF-α would play a role in brain edema formation, we examined the effects of pentoxifylline (PTX, an inhibitor of TNF-α synthesis) on the brain edema and TNF-α levels in a model of transient focal cerebral ischemia. The right middle cerebral artery (MCA) of rats was occluded for 60 min using the intraluminal filament method. The animals received PTX (60 mg/kg) immediately, 1, 3, or 6h post-ischemic induction. Twenty-four hours after induction of ischemic injury, permeability of the blood-brain barrier (BBB) and brain edema were determined by in situ brain perfusion of Evans Blue (EB) and wet-to-dry weight ratio, respectively. TNF-α protein levels in ischemic cortex were also measured at 1, 4, and 24h after the beginning of an ischemic stroke by using an enzyme-linked immunosorbent assay method. The administration of PTX up to 6h after occlusion of the MCA significantly reduced the brain edema. Moreover, PTX significantly reduced the concentration of TNF-α in ischemic brain cortex up to 4h post-transient focal stroke (P<0.002). Finally, treatment by PTX led to a significant decrease in EB extravasations (P<0.001). Our data demonstrate that PTX administration up to 6h after ischemia can reduce brain edema in a model of transient focal cerebral ischemia. The beneficial effects of PTX may be mediated, at least in part, through a decline in TNF-α production and BBB breakdown.

Pentoxifylline attenuates iminodipropionitrile-induced behavioral abnormalities in rats

This investigation was undertaken to study the effect of pentoxifylline (PTX) on iminodipropionitrile (IDPN)-induced behavioral abnormalities [excitation with choreiform and circling movements (ECC) syndrome] in rats. The animals were intraperitoneally injected with IDPN (100 mg/kg) daily for 7 days. PTX was administered daily 30 min before IDPN in the doses of 25, 50, and 100 mg/kg for 9 days. The animals were observed for neurobehavioral abnormalities including dyskinetic head movements, circling, tail hanging, air righting reflex, and contact inhibition of the righting reflex. The onset of ECC syndrome was observed on day 8 in the group treated with IDPN alone; all animals in this group became dyskinetic on day 10. Co-treatment with PTX dose dependently delayed the onset time and significantly reduced the incidence and severity of IDPN-induced ECC syndrome; high dose of PTX completely inhibited the abnormal behavioral signs in IDPN-treated rats. Administration of IDPN caused significant depletions in cerebral glutathione and vitamin E levels. Treatment with PTX dose dependently attenuated IDPN-induced oxidative stress in rats. The beneficial effects of PTX against IDPN toxicity may be attributed to its antioxidant and anti-inflammatory properties.

Anti-ischemic effect of curcumin in rat brain

Turmeric has been in use since ancient times as a condiment and due to its medicinal properties. Curcumin, the yellow colouring principle in turmeric, is polyphenolic and major active constituent. Besides anti-inflammatory, thrombolytic and anticarcinogenic activities, curcumin also possesses strong antioxidant property. In view of the novel combination of properties, neuroprotective efficacy of curcumin was studied in rat middle cerebral artery occlusion (MCAO) model. Rats were subjected to 2 h of focal ischemia followed by 72 h of reperfusion. They were pre-treated with curcumin (100 mg/kg, po) for 5 days prior to MCAO and for another 3 days after MCAO. The parameters studied were behavioural, biochemical and histological. Treatment with curcumin could significantly improve neurobehavioral performance compared to untreated ischemic rats as judged by its effect on rota-rod performance and grid walking. A significant inhibition in lipid peroxidation and an increase in superoxide dismutase (SOD) activity in corpus striatum and cerebral cortex was observed following treatment with curcumin in MCAO rats as compared to MCAO group. Intracellular calcium levels were decreased following treatment with curcumin in MCAO rats. Histologically, a reduction in the infarct area from 33% to 24% was observed in MCAO rats treated with curcumin. The study demonstrates the protective efficacy of curcumin in rat MCAO model.

Effect of aminoguanidine on post-ischemic brain edema in transient model of focal cerebral ischemia

Previous experimental studies have shown that aminoguanidine (AG) is beneficial in the late phase of cerebral ischemia. Recently, it has been reported that AG reduces cerebral edema in traumatic brain injury. However, the effects of AG on post-ischemic cerebral edema and blood-brain barrier (BBB) permeability are not clear. Under chloral hydrate anesthesia, transient focal cerebral ischemia was induced in rats by 60 min of middle cerebral artery occlusion (MCAO), followed by 23 h of reperfusion. Saline as vehicle or AG at the doses of 75, 150 and 300 mg/kg, i.p., was administered at the beginning or at 1 or 3 h after induction of ischemia. Subsequently, 24 h after MCAO brain edema, BBB permeability and infarct volume were evaluated. Administration of AG (150 mg/kg) at the beginning or at 1 or 3 h after MCAO, significantly reduced cerebral edema (P<0.001), while AG at the doses of 75 and 300 mg/kg had no effect. Moreover, treatment with AG (150 mg/kg) significantly reduces Evans Blue extravasation by 48% into ischemic brain compared to the saline group (P<0.001). Additionally, AG at the doses of 75 and 150 mg/kg significantly reduces cortical and striatal infarct volumes (P<0.001), while AG at the dose of 300 mg/kg did not change striatal infarct volumes (P>0.05). Our findings show that AG significantly reduced post-ischemic increase of brain edema with a 3-h therapeutic window in the transient model of focal cerebral ischemia. Moreover, it seems that at least part of the anti-edematous effects of AG is due to decrease of BBB disruption.