Cord Ischemia-reperfusion Injury In Rabbits Research Articles

Anti-high mobility group box-1 (HMGB1) antibody therapy for spinal cord ischemia-reperfusion injury in rabbits

Anti-high mobility group box-1 (HMGB1) antibody therapy for spinal cord ischemia-reperfusion injury in rabbits

Antioxidative and Antiapoptotic Effects of Delta-Opioid Peptide [D-Ala2, D-Leu5] Enkephalin on Spinal Cord Ischemia-Reperfusion Injury in Rabbits.

Background: In our previous study, we found that regional administration of delta-opioid peptide [D-Ala2, D-Leu5] enkephalin (DADLE) could provide dose-dependent protection on spinal cord ischemia-reperfusion (I/R) injury in rabbits. However, the relative protective molecular mechanisms underlying this neuroprotection remain unclear. The purpose of this study was to investigate whether DADLE provided the protection in spinal cord I/R injury through its antioxidant property by decreasing malondialdehyde (MDA) and nitric oxide (NO) levels and increasing glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) levels and through its antiapoptotic capacity by inhibiting caspase-3 and p53 expression.Methods: The rabbits were divided into three groups. The animals in Group NS and Group DADLE were administered with normal saline (NS) or DADLE via aorta during 30 min of ischemia respectively, while the one in Group Sham received no intervention. During the period of reperfusion, the rabbit's blood samples were collected for enzyme-linked immunoabsorbent assay (ELISA) examinations of MDA, NO, GSH-Px and SOD. At 48 h after reperfusion, the lumbar spinal cords were harvested for immunohistochemical, real-time polymerase chain reaction (PCR) and western blot studies to detect the caspase-3 and p53 expressions.Results: The activities of serum MDA and NO showed significant reductions in the DADLE group as compared with the control group. By contrast, the levels of serum GSH-Px and SOD were significantly higher in the DADLE group than those in the NS group. In addition, caspase-3 and p53 expression were significantly increased in the NS group, while DADLE mitigated these changes.Conclusions: The protective effects of DADLE at the dosage of 0.05 mg/kg may be related to its antioxidant and antiapoptosis properties in the rabbit model of spinal cord I/R injury.

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.

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.

Neuroprotective Effect of Ulinastatin on Spinal Cord Ischemia-Reperfusion Injury in Rabbits.

Ulinastatin (UTI), a trypsin inhibitor, is isolated and purified from human urine and has been shown to exert protective effect on myocardial ischemia reperfusion injury in patients. The present study was aimed at investigating the effect of ulinastatin on neurologic functions after spinal cord ischemia reperfusion injury and the underlying mechanism. The spinal cord IR model was achieved by occluding the aorta just caudal to the left renal artery with a bulldog clamp. The drugs were administered immediately after the clamp was removed. The animals were terminated 48 hours after reperfusion. Neuronal function was evaluated with the Tarlov Scoring System. Spinal cord segments between L2 and L5 were harvested for pathological and biochemical analysis. Ulinastatin administration significantly improved postischemic neurologic function with concomitant reduction of apoptotic cell death. In addition, ulinastatin treatment increased SOD activity and decreased MDA content in the spinal cord tissue. Also, ulinastatin treatment suppressed the protein expressions of Bax and caspase-3 but enhanced Bcl-2 protein expression. These results suggest that ulinastatin significantly attenuates spinal cord ischemia-reperfusion injury and improves postischemic neuronal function and that this protection might be attributable to its antioxidant and antiapoptotic properties.

Modification of the minimally invasive model for regional drug protection against spinal cord ischemia-reperfusion injury in rabbits

Objective To establish a minimally invasive model for regional aorta-infused drug protection against spinal cord ischemia-reperfusion injury in rabbits.Methods Spinal cord ischemia was induced in New Zealand rabbits by infrarenal abdominal aorta occlusion with different balloon catheters or an artery clamp for 30 min.During ischemia,normal saline or lidocaine 40 mg/kg was consecutively infused into the occluded aortic segments via a polycarbonate catheter through the femoral artery.Thereafter,blood flow was regained for reperfusion.Neurological function was assessed according to Tarlov scales postoperatively.L4-5 segements of the spinal cord were harvested at 48 h after reperfusion for histopathologic evaluation,and the total number of normal motor neurons in the anterior horn was counted.Results The 4F SwanGanz balloon catheter combined with a polycarbonate catheter was appropriate for modeling.Tarlov scores,the incidence of paraplegia (87.5％ in normal saline groups; 25.0％ vs.12.5％ in lidocaine groups) and the number of normal motor neurons [0 (0-1.75) vs.1 (0-2.00) in normal saline groups ; 8.5 (2.25-12.00) vs.9.0 (4.75-10.75) in lidocaine groups] were similar between balloon occlusion and aorta clamping while the same solution was infused (P ＞ 0.05).Conclusion The 4F Swan-Ganz balloon catheter combined with a polycarbonate catheter can be used to establish the minimally invasive model for regional drug protection against spinal cord ischemia-reperfusion instead of conventional aorta clamping in rabbits. Key words: Spinal cord ischemia; Reperfusion injury ; Aorta occlusion ; Models,animal

Effects of drug volume on the model for regional drug protection against spinal cord ischemiareperfusion injury in rabbits

Objective To compare the effects of different drug volume on the model for regional aorta-infused drug protection against spinal cord ischemia-reperfusion injury in rabbits.Methods Spinal cord ischemia model was induced in New Zealand white rabbits by infrarenal abdominal aorta occlusion with a balloon catheter for 30 min.Another polycarbonate catheter was inserted into the abdominal aorta with the tip close to the site of occlusion via the femoral artery.During the ischemic period,nothing (V0 group) or different volume (1.5,3.0 or 6.0 ml/kg) of normal saline containing methylene blue (V1.5,V3 and V6 groups) was consecutively infused into the occluded aortic segments via the polycarbonate catheter at different rate of 3.0,6.0,or 12.0 ml/(kg·h).The bilateral common iliac arteries were clamped simultaneouly to prevent drug solution leakage.Thirty min later,blood flow was regained for reperfusion.The change of mean aortic pressure distal to the occluded site was measured throughout the operation.Neurological function was assessed according to the modified Tarlov scales at the moment of palinesthesia and 6,24 and 48 h after reperfusion.Lumbar segements of the spinal cord (L4-5) were harvested at 48 h after reperfusion for histopathologic evaluation,and the total number of normal motor neurons in the anterior horn was counted.Results The abdominal aorta was not completely occluded in V6 group.In V3 and V6 groups,the distal aortic pressure during ischemia was higher than in V0 and V1.5 groups with (41.0 ± 5.5) and (49.4 ± 4.5) vs.(17.9±2.6) and (22.5±1.7) mmHg [1 mmHg=0.133kPa,P＜0.05],while the difference value between ischemia and the first 10 min of reperfusion was lower than in V0 and V1.5 groups with (44.9±8.9)and (32.3±9.4) vs.(62.5±6.3) and (61.8±4.5) mmHg (P＜0.05).Tarlovscores were higher in V6 group than in V0 group at all intervals (P ＜ 0.05).The number of normal motor neurons was greater in V6 group than in V0 group with 10 (5.0-12.0) vs.0 (0-4.5) (P＜0.05).There was no significant difference between other groups and V0 group (P ＞ 0.05).Conclusion Drug volume lower than 3 ml/kg can ensure the model stability of spinal cord injury when infused into the occluded aortic segments during the ischemic period.The optimal volume was 1.5 ml/kg. Key words: Spinal cord ischemia; Reperfusion injury; Arterial infusions; Models,animal

Effects of curcumin on acute spinal cord ischemia-reperfusion injury in rabbits

The object of this study was to conduct a prospective, randomized, laboratory investigation of the neuroprotective effects of curcumin functionally, biochemically, and histologically in an experimental acute spinal cord ischemia-reperfusion injury on rabbits. Eighteen rabbits were randomly assigned to 1 of 3 groups: the sham group, the ischemia-reperfusion group, or the curcumin group. Spinal cord ischemia was induced by applying an infrarenal aortic cross-clamp for 30 minutes. At 48 hours after ischemia, neurological function was evaluated with modified Tarlov criteria. Biochemical changes in the spinal cord and plasma were observed by measuring levels of malondialdehyde (MDA), advanced oxidation protein products (AOPP), glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), nitrite/nitrate, and tumor necrosis factor-α (TNF-α). Histological changes were examined with H & E staining. Immunohistochemical staining with antibodies against caspase-3 was performed to evaluate cell apoptosis after ischemia. In the curcumin group, neurological outcome scores were statistically significantly better compared with the ischemia-reperfusion group. In the ischemia-reperfusion group, MDA, AOPP, and nitrite/nitrate levels were significantly elevated in the spinal cord tissue and the plasma by the induction of ischemia-reperfusion. The curcumin treatment significantly prevented the ischemia-reperfusion-induced elevation of nitrite/nitrate and TNF-α. In addition, the spinal cord tissue and the plasma SOD, GSH, and CAT levels were found to be preserved in the curcumin group and not statistically different from those of the sham group. Histological evaluation of the tissues also demonstrated a decrease in axonal damage, neuronal degeneration, and glial cell infiltration after curcumin administration. Although further studies including different dose regimens and time intervals are required, curcumin could attenuate a spinal cord ischemia-reperfusion injury in rabbits via reducing oxidative products and proinflammatory cytokines, as well as increasing activities of antioxidant enzymes and preventing apoptotic cell death.

Monitoring somatosensory evoked potentials in spinal cord ischemia-reperfusion injury.

It remains unclear whether spinal cord ischemia-reperfusion injury caused by ischemia and other non-mechanical factors can be monitored by somatosensory evoked potentials. Therefore, we monitored spinal cord ischemia-reperfusion injury in rabbits using somatosensory evoked potential detection technology. The results showed that the somatosensory evoked potential latency was significantly prolonged and the amplitude significantly reduced until it disappeared during the period of spinal cord ischemia. After reperfusion for 30–180 minutes, the amplitude and latency began to gradually recover; at 360 minutes of reperfusion, the latency showed no significant difference compared with the pre-ischemic value, while the somatosensory evoked potential amplitude in-creased, and severe hindlimb motor dysfunctions were detected. Experimental findings suggest that changes in somatosensory evoked potential latency can reflect the degree of spinal cord ischemic injury, while the amplitude variations are indicators of the late spinal cord reperfusion injury, which provide evidence for the assessment of limb motor function and avoid iatrogenic spinal cord injury.

Ischemic Preconditioning Protects against Spinal Cord Ischemia-Reperfusion Injury in Rabbits by Attenuating Blood Spinal Cord Barrier Disruption

Ischemic preconditioning has been reported to protect against spinal cord ischemia-reperfusion (I-R) injury, but the underlying mechanisms are not fully understood. To investigate this, Japanese white rabbits underwent I-R (30 min aortic occlusion followed by reperfusion), ischemic preconditioning (three cycles of 5 min aortic occlusion plus 5 min reperfusion) followed by I-R, or sham surgery. At 4 and 24 h following reperfusion, neurological function was assessed using Tarlov scores, blood spinal cord barrier permeability was measured by Evan’s Blue extravasation, spinal cord edema was evaluated using the wet-dry method, and spinal cord expression of zonula occluden-1 (ZO-1), matrix metalloproteinase-9 (MMP-9), and tumor necrosis factor-α (TNF-α) were measured by Western blot and a real-time polymerase chain reaction. ZO-1 was also assessed using immunofluorescence. Spinal cord I-R injury reduced neurologic scores, and ischemic preconditioning treatment ameliorated this effect. Ischemic preconditioning inhibited I-R-induced increases in blood spinal cord barrier permeability and water content, increased ZO-1 mRNA and protein expression, and reduced MMP-9 and TNF-α mRNA and protein expression. These findings suggest that ischemic preconditioning attenuates the increase in blood spinal cord barrier permeability due to spinal cord I-R injury by preservation of tight junction protein ZO-1 and reducing MMP-9 and TNF-α expression.

Beneficial effects of hydrogen-rich saline against spinal cord ischemia-reperfusion injury in rabbits

Hydrogen-rich saline (HS) is reported to be a new therapeutic agent in ischemia-reperfusion (I/R)-induced organ damage. The present study was designed to investigate the beneficial effects of HS against spinal cord I/R injury and its associated mechanisms. Spinal cord ischemia was induced by infrarenal aortic occlusion for 20min in male New Zealand white rabbits. Different doses of HS were intravenously (i.v.) administered at 5min before or after the beginning of reperfusion. Moreover, the roles of mitochondrial ATP-sensitive potassium channels (mitoKATP), oxidative stress, inflammatory cytokines and apoptosis was assessed. Here, we found that I/R-challenged rabbits exhibited significant spinal cord injury characterized by the decreased numbers of normal motor neurons and hind-limb motor dysfunction, which was significantly ameliorated by 5mL/kg and 10mL/kg HS treatment before reperfusion or 10mL/kg HS treatment after reperfusion. However, the protective effects of HS treatment in spinal cord I/R injury were partially abolished by the selective mitoKATP channel blocker 5-hydroxydecanoate (5-HD). Moreover, we showed that the beneficial effects of 10mL/kg HS treatment against spinal cord I/R damage were associated with the decreased levels of oxidative products [8-iso-prostaglandin F2α (8-iso-PGF2α) and malondialdehyde (MDA)] and pro-inflammatory cytokines [tumor necrosis factor-alpha (TNF-α) and high-mobility group box 1 (HMGB1)], as well as the increased activities of antioxidant enzymes [superoxide dismutase (SOD) and catalase (CAT)] in serum at 6h, 12h, 24h, 48h and 72h after reperfusion and in spinal cord at 72h after reperfusion. Furthermore, HS treatment (10mL/kg) reduced caspase-3 activity in the spinal cord of this model. Thus, HS may be an effective therapeutic agent for spinal cord I/R injury via activation of mitoKATP channels as well as reduction of oxidative stress, inflammatory cytokines and apoptosis.

Intrathecal transplantation of bone marrow stromal cells attenuates blood-spinal cord barrier disruption induced by spinal cord ischemia-reperfusion injury in rabbits

Intrathecal administration of bone marrow stromal cells has been found to produce beneficial effects on ischemia-reperfusion injury to the spinal cord. The blood-spinal cord barrier is critical to maintain spinal cord homeostasis and neurologic function. However, the effects of bone marrow stromal cells on the blood-spinal cord barrier after spinal cord ischemia-reperfusion injury are not well understood. This study investigated the effects and possible mechanisms of bone marrow stromal cells on blood-spinal cord barrier disruption induced by spinal cord ischemia-reperfusion injury. This was a prospective animal study conducted at the Central Laboratory of the First Affiliated Hospital, China Medical University. The study used 81 Japanese white rabbits (weight, 1.8-2.6 kg). Spinal cord ischemia-reperfusion injury was induced in rabbits by infrarenal aortic occlusion for 30 minutes. Two days before the injury was induced, bone marrow stromal cells (1 × 10(8) in 0.2-mL phosphate-buffered saline) were transplanted by intrathecal injection. Hind-limb motor function was assessed using Tarlov criteria, and motor neurons in the ventral gray matter were counted by histologic examination. The permeability of the blood-spinal cord barrier was examined using Evans blue (EB) and lanthanum nitrate as vascular tracers. The expression and localization of tight junction protein occludin were assessed by Western blot, real-time polymerase chain reaction, and immunofluorescence analysis. Matrix metalloproteinase-9 (MMP-9) and tumor necrosis factor-α (TNF-α) expression were also measured. Intrathecal transplantation of bone marrow stromal cells minimized the neuromotor dysfunction and histopathologic deficits (P < .01) and attenuated EB extravasation at 4 hours (5.41 ± 0.40 vs 7.94 ± 0.36 μg/g; P < .01) and 24 hours (9.03 ± 0.44 vs 15.77 ± 0.89 μg/g; P < .01) after spinal cord ischemia-reperfusion injury. In addition, bone marrow stromal cells treatment suppressed spinal cord ischemia-reperfusion injury-induced decreases in occludin (P < .01). Finally, bone marrow stromal cells reduced the excessive expression of MMP-9 and TNF-α (P < .01). Pre-emptive intrathecal transplantation of bone marrow stromal cells stabilized the blood-spinal cord barrier integrity after spinal cord ischemia-reperfusion injury in a rabbit model of transient aortic occlusion. This beneficial effect was partly mediated by inhibition of MMP-9 and TNF-α and represents a potential therapeutic approach to mitigating spinal cord injury after aortic occlusion. Clinical thoracoabdominal aorta surgery may trigger spinal cord ischemia-reperfusion injury, resulting in paraplegia as well as bladder, bowel, and sexual dysfunction. Transplantation of bone marrow stromal cells has attracted increasing attention in the field of nervous system protection, but its mechanisms have not been elucidated completely. The blood-spinal cord barrier plays a crucial role to maintain normal spinal cord function. This study suggested that intrathecal transplantation of bone marrow stromal cells stabilized blood-spinal cord barrier integrity through inhibiting the upregulation of matrix metalloproteinase-9 and tumor necrosis factor-a and ameliorated spinal cord ischemia-reperfusion injury. This may provide a novel train of thought to enhance the protective effects of bone marrow stromal cells on spinal cord injury.

Neuroprotective effects of gabapentin on spinal cord ischemia-reperfusion injury in rabbits

Extensive research has been focused on neuroprotection after spinal cord trauma to alleviate the effects of secondary injury. This study aims to investigate the neuroprotective effects of gabapentin in an experimental spinal cord ischemia reperfusion injury. Thirty-two adult male New Zealand white rabbits received spinal cord ischemic injury using the aortic occlusion model. Animals were divided into 4 groups (sham, control, low-dose, and high-dose treatment groups; 8 rabbits in each group). High (200 mg/kg) and low (30 mg/kg) doses of gabapentin were administered to the animals in the treatment groups after spinal cord ischemic injury. Neurological status of the animals, ultrastructural findings in injured tissue samples, and levels of tissue injury markers in these 2 groups were compared with findings in the animals that did not receive the ischemic procedure (sham-operated group) and those that received normal saline after administration of ischemia. Regarding levels of tissue injury marker levels after ischemic injury, animals in the gabapentin-treated groups demonstrated better results than animals in the other groups. The ultrastructural findings and caspase-3 activity were similar. The treatment groups demonstrated better results than the other groups. Gabapentin demonstrated significant neuroprotection after early phases of ischemic injury. Further studies with different experimental settings including neurological outcome are required to achieve conclusive results.