Electroacupuncture preconditioning protects against focal cerebral ischemia/reperfusion injury via suppression of dynamin-related protein 1

Electroacupuncture preconditioning at acupoint Baihui(GV20) can reduce focal cerebral ischemia/reperfusion injury. However, the precise protective mechanism remains unknown. Mitochondrial fission mediated by dynamin-related protein 1(Drp1) can trigger neuronal apoptosis following cerebral ischemia/reperfusion injury. Herein, we examined the hypothesis that electroacupuncture pretreatment can regulate Drp1, and thus inhibit mitochondrial fission to provide cerebral protection. Rat models of focal cerebral ischemia/reperfusion injury were established by middle cerebral artery occlusion at 24 hours after 5 consecutive days of preconditioning with electroacupuncture at GV20(depth 2 mm, intensity 1 m A, frequency 2/15 Hz, for 30 minutes, once a day). Neurological function was assessed using the Longa neurological deficit score. Pathological changes in the ischemic penumbra on the injury side were assessed by hematoxylin-eosin staining. Cellular apoptosis in the ischemic penumbra on the injury side was assessed by terminal deoxyribonucleotidyl transferase-mediated d UTP-digoxigenin nick end labeling staining. Mitochondrial ultrastructure in the ischemic penumbra on the injury side was assessed by transmission electron microscopy. Drp1 and cytochrome c expression in the ischemic penumbra on the injury side were assessed by western blot assay. Results showed that electroacupuncture preconditioning decreased expression of total and mitochondrial Drp1, decreased expression of total and cytosolic cytochrome c, maintained mitochondrial morphology and reduced the proportion of apoptotic cells in the ischemic penumbra on the injury side, with associated improvements in neurological function. These data suggest that electroacupuncture preconditioning-induced neuronal protection involves inhibition of the expression and translocation of Drp1.

Effect of tetramethylpyrazine on the spatial learning and memory function of rats after focal cerebral ischemia

BACKGROUND: Tetramethylpyrazine (TMP) presents the effect of anti-platelet aggregation, reduces arterial resistance, increases cerebral blood flow, and improves microcirculation. OBJECTIVE: To observe the effects of TMP on the learning and memory abilities and the number of neurons in cortex and hippocampus after focal cerebral ischemia in rats DESIGN: A randomized controlled trial. SETTING: Department of Human Anatomy and Histological Embryology, School of Medicine, Xi’an Jiaotong University. MATERIALS: Fifty adult male Sprague-Dawley rats, weighing 250-300 g were supplied by the Experimental Animal Center, School of Medicine, Xi’an Jiaotong University. TMP was purchased from Wuxi Seventh Pharmaceutical Co.Ltd (Lot Number: 2004051106, Specification: 2 mL/piece). METHODS: The experiments were carried out in School of Medicine of Xi’an Jiaotong University from June 2004 to May 2005. The 50 rats were randomly divided into five groups according to the random number table method: sham-operated group, cerebral ischemia control group, low-dose TMP group, middle-dose TMP group and high-dose TMP group, 10 rats in each group. Rats in the TMP groups were immediately treated with intraperitoneal injection of TMP of 40, 80 and 120 mg/kg respectively, and those in the sham-operated group and cerebral ischemia control group were injected intraperitoneally by isovolume saline, once a day for 14 days successively. On the 15th day, the spatial learning and memory abilities of the rats were assessed with the Morris water maze test, and then the changes of neuron numbers in cortex and hippocampus were observed by Nissl staining of brain sections. MAIN OUTCOME MEASURES: The results of Morris water maze test and the changes of neuron numbers in cortex and hippocampus by Nissl staining of brain sections were observed. RESULTS: Finally 39 rats were involved in the analysis of results, and the other 11 died of excessive anesthesia or failure in model establishment. ① The rats in the cerebral ischemia control group manifested obvious spatial cognitive deficits in the place navigation trial and spatial probe trial. The mean values of escape latency in the sham-operated group, low, middle and high-dose TMP groups were obviously shorter than that in the cerebral ischemia control group [(23.92±2.21), (41.84±3.74), (39.50±3.80), (31.38±3.72), (61.60±3.61) s, P < 0.05-0.01]. In the spatial probe trial, significant differences in the percentage of time spending in the former platform quadrant and frequency of crossing the former platform site in the sham-operated group, lose, middle and high-dose TMP groups were obviously higher or more than those in the cerebral ischemia control group [(36.27±3.42) %, (35.84±2.54)%, (38.43±3.08)%, (36.51±1.96)%, (22.24±3.46)%; (11±1), (10±1), (8±1), (8±1), (4±1) times, P < 0.01]. ② In the morphological observation, the numbers of neurons in ipsilateral (left) parietal cortex in the sham-operated group, low, middle and high-dose TMP groups were obviously more than that in the cerebral ischemia control group [(98±8), (65±5), (53±6), (57±6), (37±6)/0.625 mm2, P < 0.01], but the number of neurons in left hippocampus had no obvious differences among the groups (P > 0.05). CONCLUSION: TMP can improve obviously the spatial learning and memory function after permanent focal cerebral ischemia in rats, and the neuroprotective role of the drug in cortex may be involved in its mechanism.

Vascular endothelial growth factor induced angiogenesis following focal cerebral ischemia/reperfusion injury in rabbits

BACKGROUND: Therapeutic angiogenesis has opened up new pathway for the treatment of ischemic cerebrovascular disease in recent years. The exploration of the effect of vascular endothelial growth factor (VEGF) on inducing angiogenesis following ischemia/reperfusion injury can provide better help for the long-term treatment of cerebrovascular disease in clinic. OBJECTIVE: To observe the effect of VEGF on inducing angiogenesis following focal cerebral ischemia /reperfusion injury in rabbits through the angiogenesis of microvessels reflected by the expression of the factors of vascular pseudohemophilia.DESIGN: A randomized controlled animal trial.SETTING: Department of Medical Imaging, Second Hospital of Hebei Medical University.MATERIALS: Sixty-five healthy male New Zealand rabbits of clean degree, weighing (2.6±0.2) kg, aged 4.5-5 months, were used. The polyclonal antibody against vascular pseudohemophilia (Beijing Zhongshan Company), recombinant VEGF165 (Peprotech Company, USA), biotinylated second antibody and ABC compound (Wuhan Boster Company) were applied.METHODS: The experiments were carried out in the Laboratory of Neuromolecular Imaging and Neuropathy, Second Hospital of Hebei Medical University from May to August in 2005. ① The rabbits were randomly divided into three groups: sham-operated group (n=15), control group (n=25) and VEGF-treated group (n=25). In the control group and VEGF-treated group, models were established by middle cerebral artery occlusion (MCAO) induced focal cerebral ischemia/reperfusion. In the VEGF-treated group, VEGF165 (2.5 mg/L) was stereotactically injected into the surrounding regions of the infarcted sites immediately after the 2-hour ischemia/reperfusion; Saline of the same dosage was injected in the control group. But the rabbits in the sham-operated group were only drilled but not administrated. ② The experimental indexes were observed on the 3rd, 7th, 14th, 28th and 70th days of the experiment respectively, 3 rabbits in the sham-operated group and 5 in the control group and VEGF-treated group were observed at each time point. The brain tissues in the surrounding regions of the infarcted sites were collected. The positive expressions of the factors of vascular pseudohemophilia in vascular endothelial cells were analyzed with immunohistochemical method. The microvessels in unit statistical field were counted with the imaging analytical software. MAIN OUTCOME MEASURES: The changes of microvascular density in the brain tissue and the positive expressions of the factors of vascular pseudohemophilia in the surrounding regions of the infarcted sites were observed on the 3rd, 7th, 14th, 28th and 70th days of the experiment.RESULTS: All the 65 New Zealand rabbits were involved in the analysis of results without deletion. ① Changes of the number of microvessels at different time points in each group: There were no obvious changes at different time points in the sham-operated group. The numbers of microvessels at 7 and 14 days were obviously more in the control group than in the sham-operated group [(6.0±1.1), (9.0±0.9) microvessels; (3.0±1.1), (3.0±1.1) microvessels; P < 0.05-0.01], and those at 3, 7, 14 and 28 days were obviously more in the VEGF-treated group than in the control group [(8.3±2.0), (13.4±1.4), (15.5±2.3), (6.8±1.0) microvessels; (3.4±0.6), (6.0±1.1), (9.0±0.9), (3.2±0.8) microvessels; P < 0.01]. ② Positive expressions of the factors of vascular pseudohemophilia in the surrounding regions of infarcted sites: There were no obvious changes at different time points in the sham-operated group. In the control group, the changing law of the expressions was the same as that for the number of microvessels that the expression began to mildly increase at 7 days, reached the peak value at 14 days, and began to reduce at 28 days. In the VEGF-treated group, the expression was obviously increased at 3 days, also reached the peak value at 14 days, and reduced to the normal level at 70 days, but the expressions were obviously stronger than those in the control group at the same time points.CONCLUSION: Angiogenesis can be obviously induced in rabbits after the focal cerebral ischemia/reperfusion injury is treated with VEGF for 18 days.

Effect of calcitonin gene-related peptide and nerve growth factor on spatial learning and memory abilities of rats following focal cerebral ischemia/reperfusion

BACKGROUND: Calcitonin gene-related peptide (CGRP) and nerve growth actor (NGF) cam improve spatial learning and memory abilities of rats with cerebral ischemia/reperfusion; however, the effect of combination of them on relieving learning and memory injury following cerebral ischemia/reperfusion should be further studied. OBJECTIVE: To study the effects of exogenous CGRP and NGF on learning and memory abilities of rats with focal cerebral ischemia/reperfusion. DESIGN: Randomized controlled animal study. SETTING: Department of Neurosurgery, the Second Hospital of Xiamen; Department of Neurosurgery, the Second Affiliated Hospital of China Medical University; Department of Neurobiology, Basic Medical College of China Medical University. MATERIALS: A total of 30 healthy male SD rats, aged 8 weeks, of clean grade, weighing 250-300 g, were provided by Experimental Animal Department of China Medical University. All rats were randomly divided into sham-operation group, ischemia/reperfusion group and treatment group with 10 in each group. The main reagents were detailed as the follows: 100 g/L chloral hydrate, 0.5 mL CGRP (2 mg/L, Sigma Company, USA), and NGF (1× 106 U/L, 0.5 mL, Siweite Company, Dalian). METHODS: The experiment was carried out in the Department of Neurobiology, Basic Medical College of China Medical University from February to July 2005. Rat models of middle cerebral artery occlusion were established by method of occlusion, 2 hours after that rats were anesthetized and the thread was slightly drawn out for 10 mm under direct staring to perform reperfusion. Rats in the ischemia/reperfusion group received intraperitoneal injection of 1 mL saline via the abdomen at two hours later, while rats in the treatment group at 2 hours later received intraperitoneal injection of 2 mg/L CGRP (0.5 mL) and 1×106 U/L NGF (0.5 mL) once a day for 10 successive days. First administration was accomplished within 15 minutes after ischemia/reperfusion. Rats in the sham-operation group were separated of the vessels without occlusion or administration. The neural function was evaluated with Zea Longa 5-grade scale. Animals with the score of one, two and three points received Morris water-maze test to measure searching time on platform (omitting platform-escaping latency). Meanwhile, leaning and memory abilities of animals were reflected through testing times of passing through platform per minute. MAIN OUTCOME MEASURES: Experimental results of omitting platform-escaping latency and spatial probe. RESULTS: Three and two rats in the ischemia/reperfusion group and treatment group respectively were not in accordance with the criteria in the process, and the rest were involved in the final analysis. ① Comparisons of platform-escaping latency during Morris water-maze test in all the three groups: Ten days after modeling, the platform-escaping latency in the ischemia/reperfusion group was obviously longer than that in sham-operation group (P < 0.01), and was significantly shorter than that in the treatment group (P < 0.01). ② Comparisons of times of passing through platform in all the three groups: Times of passing through platform were remarkably less in the ischemia/reperfusion group than those in the sham-operation group [(1.79±0.39), (4.30±0.73) times/minute, P < 0.01], and those were markedly more in the treatment group than the ischemia/reperfusion group [(3.16±1.03), (1.79±0.39) times/minute, P < 0.01]. CONCLUSION: CGRP and NGF are capable of ameliorating the abilities of spatial learning and memory in MCAO rats, which indicates that CGRP and NGF can protect ischemic neurons.

The neuroprotection of electro-acupuncture via the PGC-1α/TFAM pathway in transient focal cerebral ischemia rats

ATP depletion is one of the pathological bases in cerebral ischemia.Electro-acupuncture(EA)is widely used in clinical practice for ischemia.However,the mechanism of EA remains unclear.The purpose of this study was to investigate whether EA could activate the AMPK/PGC-1α/TFAM signaling pathway and,consequently,increase the preservation of ATP in rats with ischemia.In this study,48 rats were randomly divided into four groups as a sham-operation control group(sham group),a middle cerebral artery occlusion group(MCAO group),an EA group,and an EA group blocked by the AMPK inhibitor compound C(EA+CC group)(N=12/group).The rats of the EA group and EA+CC group received the EA treatment for 7 days.The rats that belonged in the two remaining groups were only grasped in the same condition.Then,their brain tissues were collected for further detection.When compared with other groups,EA significantly reduced neurological deficits score and increased motor function.The cerebral infarction volume was significantly reduced in the EA group according to TTC staining.With western blot,we found that EA improved the ratio of p-AMPKα/AMPKα(P<0.05),however,there is no difference between the MCAO group and sham group(P>0.05).In addition,EA also increased the expression of PGC-1αand TFAM(all P<0.05).By Elisa,we observed that EA increased the preservation of ATP(P<0.05)and mitochondrial respiratory enzymes,including Complex I(P<0.05),Complex IV(P<0.05),but not Complex III(P>0.05).In summary,we conclude that EA may protect against ischemic damage in MCAO rats,improve the preservation of ATP and mitochondrial respiratory enzymes.This effect may be positively regulated by the activation of the PGC-1α/TFAM signaling pathway.

Time-dependent changes of glial fibriliary acidic protein and cytosolic phospholipase A2 in hippocampal area of focal cerebral ischemia/reperfusion in rats

BACKGROUND: Interaction between astrocyte and neuron may two-dimensionally influence on ischemic injury; however, glial fibriliary acidic protein (GFAP) and cytosolic phospholipase A2 (cPLA2) are both important markers to reflect changes of astrocyte and neuron after cerebral ischemia, respectively. OBJECTIVE: To observe the changes of GFAP and positive cPLA2 cells in hippocampal area of model rats with focal cerebral ischemia in various phases of cerebral ischemia/reperfusion. DESIGN: Randomized contrast observation.SETTING: Department of Basic Medical Science, Medical College of Wuhan Polytechnic University; Faculty of Human Anatomy and Histology & Embryology, Medical College of Wuhan University. MATERIALS: The experiment was carried out in the Department of Basic Medical Science, Medical College of Wuhan Industry College from May to June 2004. A total of 28 healthy SD rats of either gender and weighing 200-250 g were provided by Animal Department of Medical College of Jianghan University.METHODS: All 28 rats were randomly divided into 7 groups, including sham operation group, 2-, 6-, 12-, 24- and 48-reperfusion groups, and triphenyltetrazolium chloride (TTC) group, with 4 in each group. Two hours after ischemia, ischemia/reperfusion models were established in left middle cerebral artery (MCA); common carotid artery was ligated and line cork was inserted into it with the depth of (1.8±0.5) cm. Rats in sham operation group were inserted with the depth of 1.0 cm, and other operations were as the same as those in 2-hour ischemia/reperfusion groups. Models in TTC group were established as the same as those in 2-hour ischemia/24-hour reperfusion group, and they were used to evaluate the therapeutic effect. Changes of GFAP and cPLA2 in hippocampal area in various phases were detected with immunohistochemical method. MAIN OUTCOME MEASURES: Changes of GFAP and positive cPLA2 cells in hippocampal area of rats with focal cerebral ischemia in various phases of ischemia/reperfusion. RESULTS: All 28 rats were involved in the final analysis without any loss. ① Animal models successfully showed the effect of focal cerebral ischemia. ② Changes of GFAP and cPLA2 in hippocampal area in various phases: Two hours after ischemia/reperfusion, changes of GFAP and cPLA2 were increased gradually, reached at peak at 24 hours, and decreased gradually. CONCLUSION: Courses of GFAP and cPLA2 are changed at the onset of focal cerebral ischemia, and this suggests that both of them participate in injury or protection of brain tissue of focal cerebral ischemia.