Neurological Deficit Scores Of Rats Research Articles

Inactivation of cGAS signaling pathway mediated by TDP-43 deficiency protects microglia from hypoxia/reoxygenation induced injury

BackgroundMicroglia are damaged during cerebral ischemia–reperfusion (I/R). This study was performed to investigate the regulatory effect of tAR DNA-binding protein-43 (TDP-43) on microglia after cerebral I/R in vitro and in vivo. MethodThe hypoxia/reoxygenation (H/R) treated microglia and rats with middle cerebral artery occlusion surgery were constructed respectively. The TDP-43 expression in brain tissues and microglia of each group was evaluated by qPCR and western blotting methods. Cell viability and cell apoptosis were combined to evaluate the degree of cell injury. As for animal experiments, neurological score and infarct volume were obtained to evaluate neurological injury. ResultsThe levels of TDP-43 in the brain tissues of I/R group were higher than that in sham group. Both TDP-43 and Iba1, a typical microglia marker, were expressed in the brain tissues. TDP-43 was also elevated in microglia with H/R treatment. Inhibition of TDP-43 significantly down-regulated neurological deficit scores of rats after I/R surgery, and weakened the H/R treatment induced injury by promoting cell viability, inhibiting cell apoptosis, down-regulating IL-6 and iNOS levels, and up-regulating Arg-1 and IL-10 levels. Inactivation of cGAS pathway mediated by TDP-43 knockdown protects microglia from H/R treatment induced injury. ConclusionThe highly expressed TDP-43 level is associated with cerebral I/R, and inhibition of TDP-43 protects microglia from H/R induced injury through cGAS pathway in vitro and in vivo.

Hypothermia prevents hippocampal oxidative stress and apoptosis via the GSK-3β/Nrf2/HO-1 signaling pathway in a rat model of cardiac arrest-induced brain damage

ABSTRACT Objectives The present study was undertaken to investigate the effects and related mechanisms of hypothermia on oxidative stress and apoptosis caused by cardiac arrest (CA)-induced brain damage in rats. Methods The CA/CPR model was initiated by asphyxia. Body temperature in the normothermia and hypothermia groups was maintained at 37°C ± 0.2°C and 34°C ± 0.2°C, respectively, by surface cooling with an ice pack. First, neurological deficit scores (NDSs) were assessed, and then hippocampus samples were collected at 24 and 72 h after return of spontaneous circulation (ROSC). Results The NDSs of rats were significantly reduced after CA, and hypothermia ameliorated neurological deficits. Varying degrees of changes in cellular nuclei and mitochondria were observed in the hippocampus following CA; however, morphological changes became less apparent after therapeutic hypothermia. Malondialdehyde (MDA) content and superoxide dismutase (SOD) activity were higher in the hippocampus at 24 h after ROSC. In contrast, hypothermia did not alter MDA content, while SOD activity further increased. Furthermore, hypothermia reversed the caspase-3 enhancement observed in the normothermia group at 24 h after ROSC. CA also inhibited GSK-3β phosphorylation, promoted Nrf2 translocation to the nucleus, and downregulated HO-1 expression. However, hypothermia significantly reversed these CA-induced changes in GSK-3β phosphorylation, Nrf2 translocation, and HO-1 expression. Conclusion Hypothermia attenuated CA-induced neurological deficits and hippocampal morphology changes in rats. The protective effect of hypothermia following CA may have been related to inhibition of oxidative stress and apoptosis, and its underlying mechanisms may have been due, at least in part, to activation of the GSK-3β/Nrf2/HO-1 pathway.

Neuroprotection of Glibenclamide against Brain Injury after Cardiac Arrest via Modulation of NLRP3 Inflammasome.

Glibenclamide (GBC) improves cerebral outcome after cardiac arrest (CA) in rats. We aim to investigate the effect of GBC on electrophysiological recovery and to explore the mechanism of neuroprotective effects of GBC on the acute stage of brain injury after the return of spontaneous circulation (ROSC) in a rodent model of CA. 16 anesthetized male Wistar rats subjected to 8-min asphyxia-CA were randomly assigned to the GBC or control group (N=8 each group). GBC was administered with a loading dose of 10ug/kg i. p. injection 10 min after ROSC and followed with a maintaining dose of 1.6ug/kg per 8 hours throughout the first 24 hours. Quantitative measures of EEG-information quantity (qEEG-IQ) and neurological deficit score (NDS) were used to predict and evaluate the functional outcome. There was a significant improvement of NDS in rats treated with GBC compared with the control group (p <; 0.01). Compared to the control group, the rats treated with GBC showed qEEG-IQ scores that indicated better recovery (p <; 0.001). Meanwhile, early QEEG-IQ was significantly correlated with 72-hr NDS as early as 45min after ROSC. Furthermore, on the molecular basis, the NLRP3 inflammasome was strongly activated in the hippocampal CA1 area 3 days after CA in control rats, which was suppressed with GBC treatment. Taken together, GBC treatment markedly improved electrophysiological and neurologic outcomes of the acute brain injury after CA. These neuroprotective effects may be associated with the attenuation of inflammatory response via down-regulation of NLRP3 inflammasome signal.

Monomethyl fumarate protects cerebral hemorrhage injury in rats via activating microRNA-139/Nrf2 axis.

Monomethyl fumarate (MF) exerts anti-inflammatory and antioxidant capacities. Whether microRNA-139 and nuclear factor (erythroid-derived 2)-like 2 (Nrf2) are involved in the pharmacological activity of MF remain unclear. We aim to elucidate the potential function of MF in intracerebral hemorrhage (ICH), and its possible mechanism. Twenty-four Sprague Dawley (SD) rats were randomly assigned into sham group, ICH group and MF group, with 8 rats in each group. Rats in ICH and MF group were subjected to ICH procedures. Rat brain tissues were harvested at 48 h after ICH procedures. Evans blue extravasation was performed to evaluate ICH-induced rat brain damage. Content of cerebral edema and neurological deficit were examined to reflect the neuronal pathological lesions. Reactive oxygen species (ROS) content in rat brain was examined by immunofluorescence. Activities of oxidative stress indexes in rat brain homogenate were detected using relative commercial kits. MicroRNA-139 expression in rat brain was quantified by quantitative Real-time polymerase chain reaction (qRT-PCR). Finally, protein levels of Nrf2, HO-1, NQO1 and nuclear factor-kappa B (NF-κB) in rat brain tissues were examined by Western blot. Compared with rats in sham group, neurological deficit scores of rats in ICH group were lower. Disruption of blood-brain barrier and brain tissue edema of rats were pronounced in ICH group. However, MF pretreatment markedly alleviated the above mentioned cerebral lesions. In addition, MF pretreatment increased activities of SOD, GSH and CAT, but decreased MDA and ROS contents in rat brain homogenate relative to those in ICH group (p<0.05). Western blot analysis found that expression levels of Nrf2, HO-1 and NQO-1 were markedly upregulated after MF pretreatment, while the expression level of NF-κB was downregulated. At the cellular level, we altered microRNA-139 expression in SH-SY5Y cells by transfection of microRNA-139 mimics or inhibitor. Overexpression of microRNA-139 remarkably increased Nrf2 expression and decreased NF-κB expression. Treatment of high-dose MF upregulated Nrf2, downregulated NF-κB and decreased ROS content in SH-SY5Y cells. MF protects ICH in rats by inhibiting oxidative stress and inflammatory response through activating microRNA-139/Nrf2 axis.

Forsythiaside A protects against focal cerebral ischemic injury by mediating the activation of the Nrf2 and endoplasmic reticulum stress pathways.

Ischemic stroke is a common type of stroke with a high mortality and morbidity rate. Preventing and controlling cerebral ischemic injury is particularly important. Forsythiaside A (FA) has been reported to have anti‑inflammatory and antioxidant activities. The aim of the present study was to explore the impact of FA on middle cerebral artery occlusion (MCAO)‑induced cerebral ischemic injury in rats. The results indicated that FA markedly increased the percent survival and decreased the neurological deficit score in rats with cerebral ischemic injury. Furthermore, cell apoptosis was significantly inhibited by FA administration, which was accompanied by decreased caspase‑3 and caspase‑9 expression. A marked increase in the expression levels of nuclear factor‑erythroid 2‑related factor 2 (Nrf2), NAD(P)H quinone dehydrogenase 1 and glutathione‑s‑transferase was detected in FA‑treated rats. In addition, treatment with FA reduced malonaldehyde expression, and enhanced the expression of superoxide dismutase and glutathione. Furthermore, endoplasmic reticulum (ER) stress was vastly alleviated by FA treatment, as evidenced by the increased expression of B‑cell lymphoma 2, apoptosis regulator and the downregulated expression of phosphorylated (phospho)‑protein kinase RNA‑like ER kinase (PERK)/PERK, phospho‑inositol‑requiring enzyme 1 (IRE1α)/IRE1α and CCAAT‑enhancer‑binding proteins homologous protein. Taken together, the present study demonstrated that FA attenuated cerebral ischemic damage via mediation of the activation of Nrf2 and ER stress pathways. These data may provide ideas for novel treatment strategies of cerebral ischemic damage.

Protective effects of ghrelin on brain mitochondria after cardiac arrest and resuscitation

Mitochondrial dysfunction plays a critical role in brain injury after cardiac arrest (CA) and cardiopulmonary resuscitation (CPR). Our recent study demonstrated that ghrelin protected against post-resuscitation brain injury with an elevated expression of mitochondrial uncoupling protein 2 (UCP2). However, the effects of ghrelin on mitochondrial dysfunction after CA are not clear. In the present study, the protective role of ghrelin was evaluated on mitochondrial dysfunction and the subsequent damage induced by CA in rats. In addition, mitochondrial unfolded protein response (UPRmt), an intrinsic cytoprotective pathway, was observed at the same time. Either vehicle (saline) or ghrelin (80 μg/kg) was injected blindly immediately after 6 min of CA and successful resuscitation. Neurological deficit was evaluated 6 h after CA and then cortex was collected for assessments. As a result, we found that ghrelin significantly improved the neurological deficit score in rats after CA. The functional analysis of isolated mitochondria revealed that ghrelin improved the mitochondrial ATP synthesis capacity and significantly reduced the reactive oxygen species (ROS) leakage after 6 h of CA. Concomitantly, we observed an increased ATP level and an attenuated oxidative stress in ghrelin treated animals. Moreover, ghrelin markedly improved the mitochondrial morphology compared with the vehicle animals. Further research revealed that ghrelin treatment significantly activated the UPRmt as demonstrated by the increased expression of heat shock protein 60 (HSP60), heat shock protein 10 (HSP10), caseinolytic protease 1 (CLPP1), and high-temperature requirement protein A2 (HTRA2). Our results suggest that ghrelin protected against cerebral mitochondria dysfunction after CA and the mechanism may involve a UPRmt pathway.

Effect of exercise preconditioning on cell apoptosis and expression of Mitokatp passage protein Kir6.2 and SUR1 in rats with cerebral ischemia-reperfusion

To implore the effect and mechanism of exercise preconditioning on neurological deficits in rats with cerebral ischemia-reperfusion (MCAO/R). Thirty-six healthy Sprague-Dawley rats were divided into model group, sham operation group and exercise preconditioning group according to the random number table. Each group consisted of 12 rats ( n = 12). A rat model of cerebral ischemia-reperfusion (MCAO/R) was established by modified suture method. After 2 h, 12 h, 24 h of reperfusion, neurological impairment was evaluated by neurological deficit score. After 24 h reperfusion, the expressions of mitoKATP channel protein Kir6.2 and SUR1 were detected by Western blot, the cerebral cell apoptosis was detected by TUENL assay. Compared with model group, neurological deficit scores of rats in exercise preconditioning group were significantly decreased ( P < 0.05). Compared with model group, exercise preconditioning group Kir6.2, SUR1 protein level and TUNEL-positive cells decreased significantly ( P < 0.05). Exercise preconditioning may improve neurological impairment after cerebral ischemia by regulating the expression of mitoK ATP channel proteins Kir6.2, SUR1 and cell apoptosis.

The impact of chronic intermittent hypoxia on the expression of intercellular cell adhesion molecule-1 and vascular endothelial growth factor in the ischemia-reperfusion rat model.

The aim of this study was to investigate the effect and mechanism of chronic intermittent hypoxia (CIH) on cerebral injury using the ischemia-reperfusion rat model. In total, 36 SD rats were divided into three groups: pseudo-surgery group (sham group), ischemia-reperfusion (IR) group (CIR group), and CIH intervention group (CIH group). The IR model was established using the suture-occluded method. CIH intervention was performed starting at 12 weeks prior to the establishment of the IR model for rats in the CIH group. Ultra-microstructure was examined using an electron microscope. Expression of intercellular cell adhesion molecule-1 (ICAM-1) and vascular endothelial growth factor (VEGF) in rat brain tissue was evaluated by immunohistochemical methods and western blot assays. The neurological deficit scores of rats in the CIH group were higher than those in the CIR group (p < 0.05). Using electron microscopy, we observed more severe edema around the capillaries of the rat brain that resulted in more pressure on the vascular wall of the capillaries in the CIH group compared to the CIR group. The expression of ICAM-1 and VEGF in rat brain tissue was rare in the sham group, but was significantly elevated in the CIR group (p < 0.05) and even higher in the CIH group, compared to the CIR group. Hence, the brain injury in ischemia-reperfusion rat models following CIH intervention may be related to the increased expression of ICAM-1 and VEGF.

Effect of bone marrow mesenchymal stem cells on angiogenesis in rats after brain injury

To explore the effect of bone marrow mesenchymal stem cells (BM-MSCs) on angiogenesis in rats after brain injury. Brain injury model of rats was established with freely fall method. A total of 50 Sprague-Dawley (SD) rats were randomly divided into a transplanted group and a control group (n=25 in each group). BM-MSCs were injected in lateral ventricle in the transplanted group, and normal saline was injected in the control group. Modified method for neurological deficit scores (mNSS) was performed at the 1, 3, 7, 21, 14 d after the operation. Flow cytometry were performed to detect CD34 and CD133 double-labeled peripheral blood cells in preoperative or 3, 6, 12, 24 h, and 3, 7 d after the operation. Expression of neuron-specific enolase (NSE) and CD31 in the brain tissues near injury area was detected by immunohistochemical SP method. There was significant difference in the MNSS scores between the 2 groups (F=5.997, P<0.05), and the difference at the different time points in each group was significant (F=37.106, P<0.01). The mNSS scores in the control group were higher than those in the transplanted group at the 7, 14, 21 d after the operation (P<0.05). The CD34 and CDl33 double positive cells (DPCs) were present in rats' peripheral blood. DPCs's numbers in peripheral blood in the control group were declined at 3 h after the sugery, they were increased and reached the highest point at 6 h after the surgery, and decreased gradually and reached normal levels at 24 h after the surgery. The same tendency was achieved in the transplanted group, and the DPCs's numbers were increased until 24 h after the surgery, which were significantly higher in the transplanted group than those in the control group at 24 h after the surgery (P<0.05). The NSE expression in the transplanted group was significantly greater than that in the control group in 7 and 14 d after the surgery (P<0.05). The expression of CD31 in the transplanted group was significantly higher than that in the control group in 3 and 7 d after the surgery (P<0.05). BM-MSCs transplantation can increase the number of peripheral blood endothelial progenitor cells after traumatic brain injury in rats and sustain for 24 h, which in turn up-regulate the angiogenesis and neuronal marker, and improve the neurological function.

Reduction in Ischemic Cerebral Infarction is Mediated through Golgi Phosphoprotein 3 and Akt/mTOR Signaling Following Salvianolate Administration

Salvianolate has been reported to possess protective properties. However, its specific mechanisms have yet to be identified. Our study aimed to identify the molecular mechanism of antioxidative stress function of salvianolate on rat ischemia and reperfusion brain tissues. Rats were randomly distributed into three experimental groups: sham, model and intervention . All animal neurobehavioral tests were performed at the end of 72-h reperfusion per Longa's method, and rats with a score of 0 (no neurological deficit) or 4 (severe neurological deficit with impaired consciousness) were excluded. Brain slices were obtained after 72 h of reperfusion and stained with triphenyltetrazolium chloride. Western blot analysis and quantitative real-time polymerase chain reaction (qRT-PCR) were used to determine levels of GOLPH3, Akt/p-Akt, and mTOR/p-mTOR expressions in ischemic cortex. Salvianolate (18mg/kg intraperitoneal injection) significantly decreased the neurological deficit scores of rats in groups of 72 h I/R and reduced the number of TUNELpositive cells in the cerebral cortex when given at onset and at 24 and 48 h after reperfusion, leading to decreased cerebral infarction in rats after ischemia/reperfusion injury. Results of Western blot and qRT-PCR showed that salvianolate could significantly upregulate the expression of Golgi phosphoprotein-3 as well as the phosphorylation of Akt and mTOR. Above findings indicate that salvianolate exerts potent and long-term neuroprotective effects in the model of cerebral I/R, and Golgi phosphoprotein-3 and its downstream activation of Akt/mTOR signaling pathway may provide a new insight for the antioxidative effect of salvianolate.

Effects of mild hypothermia on the ROS and expression of caspase-3 mRNA and LC3 of hippocampus nerve cells in rats after cardiopulmonary resuscitation.

Cardiac arrest (CA) is a common and serious event in emergency medicine. Despite recent improvements in resuscitation techniques, the survival rate of patients with CA is unchanged. The present study was undertaken to observe the effect of mild hypothermia (MH) on the reactive oxygen species (ROS) and the effect of neurological function and related mechanisms. Sixty-five healthy male Sprague Dawley (SD) adult rats were randomly (random number) divided into 2 groups: blank control group (n=5) and CPR group (n=60). CA was induced by asphyxia. The surviving rats were randomly (random number) divided into two groups: normothermia CPR group (NT) and hypothermia CPR group (HT). Normothermia of 37 °C was maintained in the NT group after return of spontaneous circulation (ROSC), hypothermal intervention of 32 °C was carried out in the HT group for 4 hours immediately after ROSC. Both the NT and HT groups were then randomly divided into 2 subgroups 12 hours and 24 hours after ROSC (NT-12, NT-24, HT-12, HT-24 subgroups). During observation, the neurological deficit scores (NDSs) was recorded, then the bilateral hippocampi were obtained from rats' head, and monoplast suspension of fresh hippocampus tissue was made immediately to determine the level of intracellular ROS by flow cytometry. Transmission electron microscope was used to observe the ultramicro changes of cellular nucleus and mitochondria. Reverse transcription-polymerase chain reaction (RT-PCR) was used to determine the expression of caspase-3 mRNA, and western-blotting (WB) was used to determine the level of LC3 in frozen hippocampus tissue. Measured data were analyzed with paired sample t test and One-Way ANOVA. Of 60 rats with CA, 44 (73%) were successfully resuscitated and 33 (55%) survived until the end of the experiment. The NDSs of rats in the NT and HT groups were more significantly reduced than those in the BC group (F=8.107, P<0.05), whereas the NDSs of rats in the HT-12 and HT-24 subgroups were significantly increased in comparison with those NDSs of rats in the NT-12 and NT-24 subgroups, respectively (t=9.692, P<0.001; t=14.374, P<0.001). The ROS in hippocampus nerve cells in the NT and HT groups significantly increased compared to the BC group (F=16.824, P<0.05), whereas the ROS in the HT-12 and HT-24 subgroups significantly reduced compared with that ROS in the NT-12 and NT-24 subgroups, respectively (t=9.836, P<0.001; t=7.499, P<0.001). The expression of caspase-3 mRNA in hippocampus nerve cells in the NT and HT groups were significantly increased compared to the BC group (F=24.527, P<0.05), whereas the expression of caspase-3 mRNA in rats of the HT-12 and HT-24 subgroups was significantly reduced compared to the NT-12 and NT-24 subgroups, respectively (t=6.935, P<0.001; t=4.317, P<0.001). The expression of LC3B-II/I in hippocampus nerve cells of rats in the NT and HT groups significantly increased compared to the BC group (F=6.584, P<0.05), whereas the expression of LC3B-II/I in rats of the HT-12 and HT-24 subgroups significantly reduced compared to the NT-12 and NT-24 subgroups, respectively (t=10.836, P<0.001; t=2.653, P=0.02). Ultrastructure damage of nucleus and mitochondria in the NT group was more evident than in the BC group, and eumorphism of nucleus and mitochondria were maintained in rats of the HT group compared with the NT group. Mild hypothermia lessened the injury of nerve cells and improved the neurological function of rats that survived from cardiac arrest by reducing the ROS production of nerve cells and inhibiting the expression of caspase-3 mRNA and LC3, leading to cellular apoptosis and massive autophagy in rats that survived from cardiac arrest after CPR.