Spinal Cord Ischemia-reperfusion Research Articles

Perfusion of gastrodin in abdominal aorta for alleviating spinal cord ischemia reperfusion injury.

To observe the effects of perfusion of the gastrodin in abdominal aorta for alleviating the spinal cord ischemia reperfusion injury (SCIRI). A total of 36 New Zealand white rabbits were divided randomly into sham-operated group (group S), control group (group C) and gastrodin group (group G), 12 rabbits for each group. Aorta abdominalis infrarenalis blocking method was applied to establish the SCIRI model. The changes of motor evoked potentials (MEPs) before the ischemia and on 30min, 60min, 6h, 12h and 24h of reperfusion of the gastrodin were respectively recorded, and the neurologic function score before the ischemia, on the 6h, 12h and 24h of the reperfusion of the gastrodin were assessed. And the changes of the concentration of serum neuron specific enolase (NSE), interleukin (IL)-lβ and IL-8 were measured before the ischemia, after 45min of ischemia, and on 30min, 60min, 6h, 12h and 24h of reperfusion of gastrodin. Then the levels of spinal cord nerve cells mitochondrial superoxide dismutase (SOD), reactive oxygen species (ROS), glutathione peroxidase (GSH-PX), malondialdehyde (MDA), total antioxidant capacity (T-AOC) and mitochondrial swelling degree (MSD) were tested and the histopathologic changes in spinal cord tissues were observed. The levels of the NSE, IL-lβ, IL-8, ROS, MDA and MSD of group C were all significantly elevated after the ischemia (P<0.01); the levels of the spinal nerve cell mitochondria SOD, GSH-PX and T-AOC were all significantly reduced (P<0.01), MEPs and spinal cord tissue pathology were damaged significantly (P<0.01). The rate of motor neuron abnormalities and the damages of spinal cord tissue pathology of group G were significantly milder than those of group C (P<0.01); the levels of NSE, IL-lβ, IL-8, ROS, MDA and MSD were significantly lower than those of group C (P<0.01), but the levels of SOD, GSH-PX and T-AOC were all significantly higher than those of group C (P<0.01), and the recovery of neurologic function score during the reperfusion of gastrodin was significantly faster than group C (P<0.01). Perfusion of the gastrodin in abdominal aorta can alleviate the spinal cord ischemiareperfusion injury by promoting the mitochondrial antioxidant capacity and inhibiting the inflammatory reaction.

Aged Garlic Extract Attenuates Neuronal Injury in a Rat Model of Spinal Cord Ischemia/Reperfusion Injury.

Garlic has been used as a food as well as a component of traditional medicine. Aged garlic extract (AGE) is claimed to promote human health through antioxidant/anti-inflammatory activities with neuroprotective effects. We evaluated the possible beneficial effect of AGE neurologically, pathologically, ultrastructurally, and biochemically in a spinal cord ischemia-reperfusion (I/R) model of rats. Twenty-four Sprague-Dawley rats were divided into three groups: sham (no I/R), I/R, and AGE (I/R+AGE); each group consisted of eight animals. Animals were evaluated neurologically with the Basso, Beattie, and Bresnahan (BBB) scoring system. The spinal cord tissue samples were harvested for pathological and ultrastructural examinations. Oxidative products (Malondialdehyde, nitric oxide), antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase), inflammatory cytokines (tissue tumor necrosis factor alpha, interleukin-1), and caspase-3 activity were analyzed. The AGE group had significantly higher BBB scores than the I/R group. Pathologically, AGE group revealed reduced degree of ischemia and spinal cord edema. Ultrastructural results also showed preservation of tissue structure in the AGE group. Oxidative product levels of the I/R group were significantly higher than both the other groups, and antioxidant enzyme levels of AGE group were significantly higher than the I/R group. There was also significant difference between the sham and AGE groups in terms of total antioxidant enzyme levels. Furthermore, AGE treatment significantly reduced the inflammatory cytokines and caspase-3 activity than the I/R group. This study demonstrates the considerable neuroprotective effect of AGE on the neurological, pathological, ultrastructural, and biochemical status of rats with I/R-induced spinal cord injury.

Impact of Heat Shock Protein A 12B Overexpression on Spinal Astrocyte Survival Against Oxygen-Glucose-Serum Deprivation/Restoration in Primary Cultured Astrocytes.

Heat shock protein A 12B (HSPA12B) is a newly discovered member of the heat shock protein 70 family. Preclinical evidence indicates that HSPA12B helps protect the brain from ischemic injury, although its specific function remains unclear. The aim of this study is to investigate whether HSPA12B overexpression can protect astrocytes from oxygen-glucose-serum deprivation/restoration (OGD/R) injury. We analyzed the effects of HSPA12B overexpression on spinal cord ischemia-reperfusion injury and spinal astrocyte survival. After ischemia-reperfusion injury, we found that HSPA12B overexpression decreased spinal cord water content and infarct volume. MTT assay showed that HSPA12B overexpression increased astrocyte survival after OGD/R treatment. Flow cytometry results showed a marked inhibition of OGD/R-induced astrocyte apoptosis. Western blot assay showed that HSPA12B overexpression significantly increased regulatory protein B-cell lymphocyte 2 (Bcl-2) levels, whereas it decreased expression of the Bax protein, which forms a heterodimer with Bcl-2. Measurements of the level of activation of caspase-3 by Caspase-Glo®3/7 Assay kit showed that HSPA12B overexpression markedly inhibited caspase-3 activation. Notably, we demonstrated that the effects of HSPA12B on spinal astrocyte survival depended on activation of the PI3K/Akt signal pathway. These findings indicate that HSPA12B protects against spinal cord ischemia-reperfusion injury and may represent a potential treatment target.

Effects of Aloe Vera on Spinal Cord Ischemia–Reperfusion Injury of Rats

ABSTRACTAim: The purpose of this study was to evaluate the possible protective/therapeutic effects of aloe vera (AV) on ischemia–reperfusion injury (I/R) of spinal cord in rats. Materials and Methods: A total of 28 Wistar Albino rats were divided into four random groups of equal number (n = 7). Group I (control) had no medication or surgery; Group II underwent spinal cord ischemia and was given no medication; Group III was administered AV by gastric gavage for 30 days as pre-treatment; Group IV was administered single dose intraperitoneal methylprednisolone (MP) after the ischemia. Nuclear respiratory factor-1 (NRF1), malondialdehyde (MDA) and superoxide dismutase (SOD) levels were evaluated. Tissue samples were examined histopathologically and neuronal nitric oxide synthase (nNOS) and nuclear factor-kappa B (NF-κB) protein expressions were assessed by immunohistochemical staining. Results: NRF1 and SOD levels of ischemia group were found to be lower compared to the other groups. MDA levels significantly increased after I/R. Treatment with AV and MP resulted in reduced MDA levels and also alleviated hemorrhage, edema, inflammatory cell migration and neurons were partially protected from ischemic injury. When AV treatment was compared with MP, there was no statistical difference between them in terms of reduction of neuronal damage. I/R injury increased NF-κB and nNOS expressions. AV and MP treatments decreased NF-κB and nNOS expressions.Conclusions: It was observed that aloe vera attenuated neuronal damage histopathologically and biochemically as pretreatment. Further studies may provide more evidence to determine the additional role of aloe vera in spinal cord ischemia reperfusion injury.

Protection of rats spinal cord ischemia-reperfusion injury by inhibition of MiR-497 on inflammation and apoptosis: Possible role in pediatrics.

MicroRNAs are extensively included in the pathogenesis and progression of many diseases by inhibiting target gene expression. Recently, studies have demonstrated that microRNA-497 (miR-497) may be implicated in human breast cancer that miR-497 predicts the prognosis of breast cancer patients from the posttranscriptional level. However, the specific function of miR-497 in spinal cord ischemia-reperfusion (IR) injury is far from clear nowadays. The present study was designed to determine the role of miR-497 in spinal cord IR injury and investigate the underlying spinal cord protective mechanism. The rat spinal cord IR injury model was performed by occluding the left anterior descending coronary artery for 30 min, which is then followed by 12h reperfusion. As predicted, miR-497 over-expression markedly decreased the expression of IL-1 receptor associated kinase (IRAK1) and Cyclic AMP response element binding protein (CREB). Moreover, Toll-like receptor 4 (TLR4), nuclear factor-kappa B (NF-κB) and Caspase-3, as miR-497 potential targets were significantly suppressed after miR-497 transfection, then preventing inflammatory cytokines and factors regulating apoptosis. We also found that tumor necrosis factor-a (TNF-α) and interleukin-1beta (IL-1β) activity, pro-apoptotic related genes, such as extracellular regulated protein kinases (ERK), Bcl-2 Associated X Protein (Bax), Bcl-2, Bcl-xL levels were all decreased associated with the down-regulation of IRAK1 and CREB. In conclusion, our data demonstrate that miR-497 could inhibit inflammation and apoptosis of spinal cord IR through its targets, IRAK1 of TLR4 and CREB signaling pathway. Thus, miR-497 may constitute a new therapeutic target for the prevention of spinal cord IR injury.

Role of autophagy in the bimodal stage after spinal cord ischemia reperfusion injury in rats

Autophagy plays an important role in spinal cord ischemia reperfusion (I/R) injury, but its neuroprotective or neurodegenerative role remains controversial. The extent and persistence of autophagy activation may be the critical factor to explain the opposing effects. In this study, the different roles and action mechanisms of autophagy in the early and later stages after I/R injury were investigated in rats. Thespinal cord I/R injury was induced by 14-min occlusion of the aortic arch, after which rats were treated with autophagic inhibitor (3-methyladenine, 3-MA) or agonist (rapamycin) immediately or 48h following the injury. Autophagy markers, microtubule-associated protein light chain 3-II (LC3-II) and Beclin 1 increased and peaked at the early stage (8h) and the later stage (72h) after spinal cord I/R injury. Beclin 1 was mostly expressed in neurons, but was also expressed to an extent in astrocytes, microglia and vascular endothelial cells. 8h after injury, rats treated with 3-MA showed a decrease in the hind-limb Basso–Beattie–Bresnahan (BBB) motor function scores, surviving motor neurons, and B-cell lymphoma-2 (Bcl-2) expression, and increase in the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labeling (TUNEL)-positive cells, Bcl-2-associated X protein (Bax), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) expression, and activation of microglia, while those treated with rapamycin showed opposing effects. However, 72h after injury, rats treated with 3-MA improved the BBB scores, and the surviving motor neurons, and reduced the autophagic cell death, while those treated with rapamycin had adverse effects. These findings provide the first evidence that early activated autophagy alleviates spinal cord I/R injury via inhibiting apoptosis and inflammation; however later excessively elevated autophagy aggravates I/R injury through inducing autophagic cell death.

Curcumin Attenuates Inflammation, Oxidative Stress, and Ultrastructural Damage Induced by Spinal Cord Ischemia–Reperfusion Injury in Rats

Curcumin is a molecule found in turmeric root that possesses anti-inflammatory and antioxidant properties and has been widely used to treat neurodegenerative diseases. We investigated whether curcumin stimulates the neurorepair process and improves locomotor function in a rat model of spinal cord ischemia-reperfusion injury. Thirty-two Wistar albino rats (190-220 g) were randomly allocated into 4 groups of 8 rats each: 1 sham-operated group and 3 ischemia-reperfusion injury groups that received intraperitoneal injections of saline vehicle, methylprednisolone (MP, 30 mg/kg following induction of ischemia-reperfusion [IR] injury), or curcumin (200 mg/kg for 7 days before induction of IR injury). Spinal cord IR injury was induced by occlusion of the abdominal aorta for 30 minutes. After 24 hours of reperfusion, locomotor function was assessed using the Basso, Beattie, and Bresnahan scale. All animals were sacrificed. Spinal cord tissues were harvested to evaluate histopathological and ultrastructural alterations and to analyze levels of malondialdehyde, tumor necrosis factor-alpha, interleukin-1 beta, nitric oxide, and caspase-3, as well as enzyme activities of superoxide dismutase and glutathione peroxidase. Intraperitoneal administration of curcumin significantly reduced inflammatory cytokine expression, attenuated oxidative stress and lipid peroxidation, prevented apoptosis, and increased antioxidant defense mechanism activity in comparison to treatment with MP or saline. Histopathological and ultrastructural abnormalities were significantly reduced in curcumin-treated rats compared to the MP- and saline-treated groups. Furthermore, curcumin significantly improved locomotor function. Curcumin treatment preserves neuronal viability against inflammation, oxidative stress, and apoptosis associated with ischemia-reperfusion injury.

Modulation of the neurological and vascular complications by grape seed extract in a rat model of spinal cord ischemia-reperfusion injury by downregulation of both osteopontin and cyclooxygenase-2.

In this study, we investigated the effects of grape seed extract (GSE) on the expression of osteopontin (OPN) and cyclooxygenase-2 (COX-2) in a rat model of spinal cord ischemia-reperfusion injury (SC-IRI). Fifty male rats were divided into 5 groups: control (CON); control + GSE (CON + GSE) (received GSE for 28 days); sham operated (Sham); IRI; and IRI + GSE. SC-IRI was induced by clamping the aorta just above the bifurcation for 45 min, and then the clamp was released for 48 h for reperfusion. IRI + GSE group received GSE for 28 days before SC-IRI. Sensory, motor, and placing/stepping reflex assessment was performed. Prostaglandin E2 (PGE2), thiobarbituric acid reactive substances (TBARs), and total antioxidant capacity (TAC) were measured in spinal cord homogenate. Immunohistochemical examination of the spinal cord for OPN and COX-2 were carried out. SC-IRI resulted in significant increase in plasma nitrite/nitrate level and spinal cord homogenate levels of TBARs and PGE2, and OPN and COX-2 expression with significant decrease in TAC. GSE improves the sensory and motor functions through decreasing OPN and COX-2 expression with reduction of oxidative stress parameters. We conclude a neuroprotective effect of GSE in SC-IRI through downregulating COX-2 and OPN expression plus its antioxidants effects.

Neuroprotective effects of thymoquinone against spinal cord ischemia-reperfusion injury by attenuation of inflammation, oxidative stress, and apoptosis.

OBJECTIVE Ischemia-reperfusion (I/R) injury of the spinal cord following thoracoabdominal aortic surgery remains the most devastating complication, with a life-changing impact on the patient. Thymoquinone (TQ), the main constituent of the volatile oil from Nigella sativa seeds, is reported to possess strong antioxidant, antiinflammatory, and antiapoptotic properties. This study investigated the effects of TQ administration following I/R injury to the spinal cord. METHODS Thirty-two rats were randomly allocated into 4 groups. Group 1 underwent only laparotomy. For Group 2, aortic clip occlusion was introduced to produce I/R injury. Group 3 was given 30 mg/kg of methylprednisolone intraperitoneally immediately after the I/R injury. Group 4 was given 10 mg/kg of TQ intraperitoneally for 7 days before induction of spinal cord I/R injury, and administration was continued until the animal was euthanized. Locomotor function (Basso, Beattie, and Bresnahan scale and inclined plane test) was assessed at 24 hours postischemia. Spinal cord tissue samples were harvested to analyze tissue concentrations of malondialdehyde, nitric oxide, tumor necrosis factor-α, interleukin-1, superoxide dismutase, glutathione-peroxidase, catalase, and caspase-3. In addition, histological and ultrastructural evaluations were performed. RESULTS Thymoquinone treatment improved neurological outcome, which was supported by decreased levels of oxidative products (malondialdehyde and nitric oxide) and proinflammatory cytokines (tumor necrosis factor-α and interleukin-1), increased activities of antioxidant enzymes (superoxide dismutase, glutathione-peroxidase, and catalase), as well as reduction of motor neuron apoptosis. Light microscopy and electron microscopy results also showed preservation of tissue structure in the treatment group. CONCLUSIONS As shown by functional, biochemical, histological, and ultrastructural analysis, TQ exhibits an important protective effect against I/R injury of the spinal cord.

Function of SOD1, SOD2, and PI3K/AKT signaling pathways in the protection of propofol on spinal cord ischemic reperfusion injury in a rabbit model

AimsTo verify that co-application of propofol preconditioning and postconditioning protects spinal cord from ischemia/reperfusion injury by enhancing the different subtypes of SOD activity, which is related to PI3K/AKT signal pathway. Materials and methods60 rabbits were randomly equally assigned to 3 groups: Group S, sham-operation group; Group I/R., ischemia/reperfusion group; Group P, ischemia/reperfusion group with propofol treatment. Four rabbits per group were randomly executed at the time-points: days 1, 2, 3, 5, and 7 post-surgery. Spinal cord tissues at L3 to L4 levels were harvested. The bioactivities of SOD1 and SOD2, and the mRNA expression levels of SOD1, SOD2, PI3K, and AKT were detected. Key findingsOn day 1, the bioactivity of SOD1 increased significantly in Group I/R or Group P compared with Group S (P<0.05). On day 2, compared with Group S, the bioactivity of SOD1 increased significantly in Group P (P<0.05). On days 3, 5, and 7, the bioactivity of SOD1 decreased significantly respectively in Group I/R compared with Group S (P<0.05). On all timepoints, the bioactivity of SOD2 decreased significantly in Group I/R compared with Group S (P<0.05). There was a positive correlation between the SOD1 activity and the respective mRNA expression of SOD1, PI3K, and AKT. SignificanceCo-application of propofol preconditioning and postconditioning resulted in potent protective effects against spinal cord ischemia/reperfusion injury, which was associated with the increased expression of SOD1 in spinal cord tissues by activating PI3K/AKT signal pathway.

Neuroprotective Effects of Pregabalin Against Spinal Cord Ischemia-Reperfusion Injury in Rats.

To evaluate the effect of pregabalin pre-treatment on spinal cord ischemia-reperfusion (I/R) injury and compare with methylprednisolone (MP). Thirty-two rats were randomly divided into four groups as follow: Group 1 (sham)(n=8), group 2 (ischemia only)(n=8), group 3 (30 mg/kg pregabalin)(n=8), and group 4 (30 mg/kg methylprednisolone)(n=8). Laparotomy was performed without aortic clamp in the sham group. All animals were sacrificed 24 hours after surgery. The spinal cord tissue samples were harvested and caspase-3 activity, tumor necrosis factor-alpha (TNF-α) and Interleukin-1 Beta (IL-1β) levels, catalase (CAT) activity, glutathione peroxidase (GPx) activity, superoxide dismutase (SOD) levels malondialdehyde (MDA) levels and nitric oxide (NO) levels were analyzed to investigate the effects of different excitatory and inflammatory pathways in mechanism of I/R injury. Ultrastructural and histopathological examinations were carried out. Neurological recovery was measured by Basso, Beattie, Bresnahan (BBB) test and Inclined Plane Test. Decresead caspase-3 activity and decreased inflammatory markers like TNF-α, IL-1β, and decresaed excitotatory pathways like CAT, GPx, MDA, NO and SOD were observed in both pregabalin pre-treatment and MP treatment groups. Pregabalin pre-treatment produced better ultrastructural results compared to MP treatment, as with histopathological examination. Pregabalin group showed better recovery compared to MP treament group according to BBB scoring system. Pregabalin pre-treatmet and MP treatment both has neuroprotective effect on I/R injury by decreasing caspase dependant apoptosis, and inflammatory and oxidative stress markers. In addition, pregabalin pre-treatment had better clinical effects compared to MP treatment.

Effects of Atorvastatin on Experimental Spinal Cord Ischemia-Reperfusion Injury in Rabbits.

Extent of secondary injury is the determinant of tissue destruction and functional worsening after primary spinal cord injury (SCI). Data have accumulated on alleviation of secondary injury in SCI from many studies on the subject. Besides its cholesterol lowering effects, statins are known to have anti-inflammatory and anti-oxidant effects which are the main targets of spinal cord research. This study aims to evaluate the effects of atorvastatin on experimental spinal cord ischemia-reperfusion injury. Thirty adult male New Zealand rabbits were allocated into control, ischemia-reperfusion (I/R) and treatment groups. Treatment group received 5 mg/kg of atorvastatin via lavage for the preceding 14 days. Other groups received placebo during the same time period. After two weeks, animals in the I/R and treatment groups underwent abdominal temporary aorta occlusion for 30 minutes. Neurological condition of the animals was recorded during the 48 hours of observation. Afterwards, animals were sacrificed and levels of malondialdehyde, glutathione and nitric oxide in spinal cord tissue and plasma and the histopathological tissue changes were determined. Animals in the treatment groups demonstrated significantly better results than the I/R group regarding biochemical markers. Neurological evaluation using the Tarlov scale demonstrated significantly better results at the 48th hour in treatment group. Histopathological results were also better in the treatment groups. Results of this study demonstrate the neuroprotective effects of atorvastatin. Atorvastatin has favorable effects on biochemical markers of oxidative stress in SCI. Further studies with larger cohorts and different time periods are also needed.

The effects of IL-18BP on mRNA expression of inflammatory cytokines and apoptotic genes in renal injury induced by infrarenal aortic occlusion

BackgroundRenal injury is an important complication of infrarenal aortic occlusion (IAO), which is mainly encountered during the postoperative period. Aortic clamping procedure may lead to turbulent blood flow and eventually vasoconstriction at renal arterial level of the abdominal aorta. IL-18BP has well-known antioxidant and anti-inflammatory properties. In this study, we aimed to determine whether IL-18BP has anti-inflammatory, antiapoptotic, antioxidant, and protective effects on acute kidney damage induced by IAO rat model. Materials and methodsA total of 30 adult male Wistar-Albino rats were equally and randomly separated to three groups as follows: SHAM laparotomy, ischemia-reperfusion (IR), and IR + IL-18BP. We applied 30-min IAO and 2-h reperfusion. Inflammatory cytokine levels (TNF-α, IL-1β, IL-18, IL-6, and IFN-γ) and oxidative stress parameters (TAS, TOS, and OSI) were measured. In addition to this, urea and creatinine levels, histopathology of kidney, mRNA expression levels of inflammatory cytokines, and apoptotic genes were investigated. ResultsUrea and creatinine, tissue and serum levels of TNF-α, IL-6, IL-18, IFN-γ, and TOS, and oxidative stress index (OSI) were found significantly lower in IR + IL-18BP group, when compared to the IR group. Moreover, mRNA expression levels of inflammatory cytokines and apoptotic genes were prominently depressed in IR + IL-18BP pre-treatment group in histopathologic examination, there was a significant difference between the IR and other three groups (P < 0.001). These improvements were demonstrated with a total score of histopathologic damage. In our previous studies, we have demonstrated that IL-18BP has antioxidant, inflammatory, and protective effects on liver and spinal cord IR injury. Data established from the present study suggest that IL-18BP may exert anti-inflammatory, antiapoptotic, antioxidant, and protective effects on IAO-induced acute kidney injury in rats, and this would be the first study to be conducted in this field. ConclusionsData established from the present study suggest that IL-18BP may exert anti-inflammatory, antiapoptotic, antioxidant, and protective effects on IAO-induced acute kidney injury in rats.

PMX53 protects spinal cord from ischemia-reperfusion injury in rats in the short term.

Experimental study. To investigate the effect of pre-treatment with PMX53, a C5aR antagonist, on spinal cord ischemia-reperfusion injury (IRI) in rat. Department of Neurosurgery, Second Affiliated Hospital, Xi'an Jiaotong University School of Medicine, Xi'an, Shaanxi Province, China. IRI was induced in the lumbar spinal cord by applying a mini aneurysm clamp to the abdominal aorta for 60 min in adult Sprague-Dawley rats. PMX53 (1 mg kg(-1)) was administered through femoral vein injection 30 min before ischemia on the rats in the PMX53 group (n=18). The saline group (n=18) was given saline at the same volume through femoral vein injection. The neurologic outcome of the posterior limbs was assessed by the Basso-Beattie-Bresnahan (BBB) score at 1, 6, 12, 24 and 48 h after reperfusion. Histologic changes of the spinal cord were detected with hematoxylin-eosin (H-E) staining. Enzyme-linked immunosorbent assay (ELISA) was used to detect myeloperoxidase (MPO) activity in the spinal cord. Immunohistochemistry was used to investigate the quantity of activated astrocytes and microglia. After pre-treatment with PMX53, neurologic function improved gradually after 6, 12, 24 and 48 h reperfusion. The BBB score of the PMX53 group increased significantly (P<0.05) compared with the saline group. H-E staining showed that pathologic damage in the PMX53 group was reduced. Moreover, administration of PMX53 significantly inhibited neutrophil infiltration in the spinal cord. Levels of MPO activity in the spinal cord were remarkably lower in the PMX53 group (P<0.05). There were also more activated microglia and astrocytes in the spinal cord of the PMX53 group than in the saline group (P<0.05). PMX53 delivered 30 min prior to ischemic injury protects the spinal cord from IRI, probably via the inhibition of neutrophil activity, increased activated microglia and astrocyte.

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.

Effect of lactulose on spinal cord ischemia-reperfusion injury in rats

Objective To evaluate the effect of lactulose on spinal cord ischemia-reperfusion(I/R)injury in rats. Methods One hundred forty-four male Sprague-Dawley rats, aged 3 months, weighing 300-350 g, in which gastric tube was successfully inserted, were randomly divided into 4 groups(n=36 each)using a random number table: sham operation group(group S), spinal cord I/R group(group I/R), lactulose group(group L), and lactulose+ antibiotics group(group LA). Spinal cord ischemia was induced by occlusion of the thoracic aorta combined with controlled hypotension for 9 min, followed by reperfusion.Lactulose 0.5 g/kg was administered intragastrically immediately after onset of reperfusion in group L. Metronidazole 30 mg/kg and gentamicin 40 mg/kg were administered intragastrically three times a day during 1-3 days before operation in group LA, and the other procedures were similar to those previously described in group L. Hydrogen concentration in cerebrospinal fluid was detected before ischemia and at 10, 30, 60, 90, 120, 150 and 180 min after reperfusion.At 12, 24 and 48 h of reperfusion, 8 rats in each group were sacrificed, and the L3-5 segment of the spinal cord was isolated for determination of nuclear factor E2-related factor 2(Nrf2)expression(by Western blot), superoxide dismutase(SOD)activity(by using xanthine oxidase method), catalase(CAT)activity(ammonium molybdate method), and 8-hydroxy-2'-deoxyguanosine(8-OHdG), 3-nitrotyrosine(3-NT)and malondialdehyde(MDA)contents(by ELISA). Neurological function was assessed and scored at 48 h of reperfusion.Six animals in each group were then sacrificed after assessment of neurological function, and the L3-5 segment of the spinal cord was removed for detection of apoptotic neurons.The cell survival rate and apoptotic rate were calculated. Results Compared with group S, no significant change was found in the hydrogen concentration in the cerebrospinal fluid at each time point, and in the level of Nrf2, CAT and SOD at 12, 24 and 48 h of reperfusion, the contents of 8-OHdG, 3-NT and MDA were significantly increased, the neurological scores and cell survival rate were decreased, and the apoptotic rate was increased in group I/R, and the hydrogen concentration in the cerebrospinal fluid at 30-180 min of reperfusion was increased, the level of Nrf2, CAT and SOD was increased at 12, 24 and 48 h of reperfusion, and no significant change was found in the contents of 8-OHdG, 3-NT and MDA, neurological scores, cell survival rate, and apoptotic rate in group L. Compared with group I/R, the hydrogen concentration in the cerebrospinal fluid at 30-180 min of reperfusion was increased, the level of Nrf2, CAT and SOD was increased, the contents of 8-OHdG, 3-NT and MDA were decreased, the neurological scores and cell survival rate were increased, and the apoptotic rate was decreased in group L, and no significant change was found in the parameters mentioned above in group LA. Conclusion Lactulose can reduce spinal cord I/R injury in rats. Key words: Lactulose; Spinal cord; Reperfusion injury

Hydrogen sulfide protects spinal cord and induces autophagy via miR-30c in a rat model of spinal cord ischemia-reperfusion injury.

BackgroundHydrogen sulfide (H2S), a novel gaseous mediator, has been recognized as an important neuromodulator and neuroprotective agent in the nervous system. The present study was undertaken to study the effects of exogenous H2S on ischemia/reperfusion (I/R) injury of spinal cord and the underlying mechanisms.MethodsThe effects of exogenous H2S on I/R injury were examined by using assessment of hind motor function, spinal cord infarct zone by Triphenyltetrazolium chloride (TTC) staining. Autophagy was evaluated by expressions of Microtubule associated protein 1 light chain 3 (LC3) and Beclin-1 which were determined by using Quantitative Real-Time PCR and Western blotting, respectively.ResultsCompared to I/R injury groups, H2S pretreatment had reduced spinal cord infarct zone, improved hind motor function in rats. Quantitative Real-Time PCR or Western blotting results showed that H2S pretreatment also downregulated miR-30c expression and upregulated Beclin-1 and LC3II expression in spinal cord. In vitro, miR-30c was showed to exert negative effect on Beclin-1 expression by targeting its 3’UTR in SY-SH-5Y cells treated with Oxygen, Glucose Deprivation (OGD). In rat model of I/R injury, pretreatment of pre-miR-30c or 3-MA (an inhibitor for autophagy) can abrogated spinal cord protective effect of H2S.ConclusionH2S protects spinal cord and induces autophagy via miR-30c in a rat model of spinal cord hemia-reperfusion injury.

Neuroprotective Effects of Rosuvastatin in Spinal Cord Ischemia-Reperfusion Injury in Rabbits

Background: This experimental study was performed to investigate the neuroprotective effects of rosuvastatin in a rabbit model of spinal cord ischemia-reperfusion injury. Materials and Methods: Rabbits were randomized into 3 groups of 6 animals each: group 1 (control), group 2 (ischemia), and group 3 (rosuvastatin 5 mg/kg/d). Spinal cord ischemia was produced in rabbits by a 30-minute occlusion of the aorta by clamping with aneurysm clips; just caudal to renal artery divison and above the aortic bifurcation. Rosuvastatin was administered intraperitoneally before onset of occlusion, for 3 days. At 48 hours after ischemia, neurological evaluation was performed using the Basso, Beattie, and Bresnahan locomotor rating scale before they were killed. Levels of malondialdehyde (MDA), glutathione, advanced oxidation protein products (AOPP), superoxide dismutase, catalase, nitrite/nitrate, and tumor necrosis factor-α were measured in the spinal cord tissue and plasma. Histopatologic evaluation of the tissues and activation of caspase 3 were also studied. Results: Basso, Beattie, and Bresnahan scores for rosuvastatin group were significantly higher. MDA, AOPP, and nitrite/nitrate levels in the ischemia group were significantly higher than those for control and rosuvastatin groups (P<0.05). There were no significant differences in MDA, AOPP, and nitrite/nitrate levels between rosuvastatin and control groups. In rosuvastatin group, spinal cord tissue and plasma superoxide dismutase, glutathione, and catalase levels were significantly increased compared with the ischemia group. The gross histopathologic examination demonstrated decrease in axonal damage, neuronal degeneration, and glial cell infiltration after rosuvastatin treatment. Conclusions: Rosuvastatin may protect the spinal cord tissue against ischemic damage, by its anti-inflammation and antiapoptotic effect. Although further studies including different dose regimens and time intervals are required, this drug may therefore be a good candidate for clinical use during surgical procedures on the thoracoabdominal aorta.

Expression of C5a and its receptor following spinal cord ischemia reperfusion injury in the rat.

Experimental study. To investigate the expression of C5a and its receptor after spinal cord ischemia reperfusion injury (SIRI) in rat. Department of Neurosurgery, the Second Affiliated Hospital, Xi'an Jiaotong University, Shaanxi Province, Xi'an, China Sprague Dawley rats were subjected to 1 h of infrarenal aorta occlusion to induce spinal cord ischemia. Spinal cord was reperfused for 12, 24, 48 h or 3 days separately after ischemia, respectively. Enzyme-linked immunosorbent assay was used to detect C5a in rat serum. Immunofluorescent staining was performed to detect the expression and cellular localization of C5aR in spinal cord following SIRI. Following SIRI, the motor behavior of the rats was significantly compromised. The serum concentration of C5a in the rat was elevated after SIRI and peaked at 24 h. C5aR was significantly upregulated in the lumbar spinal cord following SIRI and expressed on motor neurons and the microglia, but not astrocyte. There was no significant difference in the expression level of C5aR localized on motor neurons after SIRI. Remarkable upregulation of the C5aR may be associated with increased number of C5aR-positive microglia and elevated cellular expression level. This study provides the first evidence of the expression of C5a and its receptors in SIRI and suggests their possible contribution to SIRI in a rat model.

The protective effect of hypoxic-preconditioned BMSCs on spinal cord tissue after ischemia reperfusion injury in rats

Objective To investigate the protective effect of hypoxic-preconditioned bone marrow mesenchymal stem cells (BMSCs) on spinal cord tissue after ischemia reperfusion injury. Methods Healthy adult Sprague Dawley (SD) rats weighing 200~250 grams (g) were randomly divided into 3 groups with 6 animals in each group: The sham group received simple surgical manipulation without ischemia/reperfusion treatment; The spinal cord ischemia/reperfusion group (Control group) only received spinal cord ischemia/reperfusion surgery. The hypoxic preconditioned BMSC transplantation group (HP-MSCs group) was injected with hypoxic preconditioned BMSCs 2 days before ischemia/reperfusion. The control group, HP-MSCs group received spinal cord ischemia/reperfusion for 10 min and observed for 48 h. The permeability of the blood-spinal cord barrier was examined with Evans blue (EB), and the histomorphology changes were observed with hematoxylin and eosin (HE) staining. Results EB red fluorescence was significantly weakened in the HP-MSCs group than that in the Control group (P<0.05=, and more intact motor neurons were found in the lumbar spinal cords in the HP-MSCs group than that in the Control group(P<0.05=. Conclusions The hypoxic-preconditioned BMSCs could effectively attenuate spinal cord ischemia reperfusion injury, it may be associated with protective effect of the blood-spinal cord barrier integrity. Key words: Anoxia; Hematopoietic stem cell transplantation; Mesenchymal stem cell transplantation; Spinal cord ischemia/SU; Reperfusion injury/SU