Icariin mitigates anxiety-like behaviors induced by hemorrhagic shock and resuscitation via inhibiting of astrocytic activation.

BACKGROUND: Abnormal activation of astrocytes in the amygdala contributes to anxiety after hemorrhagic shock and resuscitation (HSR). Nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB)-associated epigenetic reprogramming of astrocytic activation is crucial to anxiety. A bioactive monomer derived from Epimedium icariin (ICA) has been reported to modulate NF-κB signaling and astrocytic activation. PURPOSE: The present study aimed to investigate the effects of ICA on post-HSR anxiety disorders and its potential mechanism of action. METHODS: We first induced HSR in mice through a bleeding and re-transfusion model and selectively inhibited and activated astrocytes in the amygdala using chemogenetics. Then, ICA (40 mg/kg) was administered by oral gavage once daily for 21 days. Behavioral, electrophysiological, and pathological changes were assessed after HSR using the light-dark transition test, elevated plus maze, recording of local field potential (LFP), and immunofluorescence assays. RESULTS: Exposure to HSR reduced the duration of the light chamber and attenuated open-arm entries. Moreover, HSR exposure increased the theta oscillation power in the amygdala and upregulated NF-κB p65, H3K27ac, and H3K4me3 expression. Contrarily, chemogenetic inhibition of astrocytes significantly reversed these changes. Chemogenetic inhibition in astrocytes was simulated by ICA, but chemogenetic activation of astrocytes blocked the neuroprotective effects of ICA. CONCLUSION: ICA mitigated anxiety-like behaviors induced by HSR in mice via inhibiting astrocytic activation, which is possibly associated with NF-κB-induced epigenetic reprogramming.

Role of SIRTl/Nrf2/HO-l pathway in attenuation of learning and memory impairment by sevoflurane postcondition in a mouse model of hemorrhagic shock and resuscitation / 中国药理学通报

Aim To explore the role of SIRT1/Nrf2 / HO-1 in alleviating the cognitive function impairment by sevoflurane treatment in a mouse model of postoperative cerebral reperfusion. Methods C57BL/6J mice were randomly divided into five groups: sham operation group, hemorrhagic shock reperfusion group, sevoflurane postconditioning group, sevoflurane postcondition-ing + SIRT1 inhibitor group and sevoflurane postconditioning + Nrf2 inhibitor group. Mice were subjected to Morris water maze test after cerebral ischemia reperfusion. The ATP, superoxide dismutase (SOD), ROS and MDA contents in tissue of mice were detected. SIRT1, Nrf2 and HO-1 proteins in tissue were detected by Western blot. Results After hemorrhagic shock, the learning and memory ability of mice was reduced.ATP and SOD concentration in hippocampus was reduced , MDA and ROS concentration increased, and the SIRT, Nrf2 and HO-1 concentration was reduced. Sevoflurane improved the cognitive dysfunction and oxi-dative damage in postoperative mice, and the neuro-protective effect of sevoflurane on hemorrhagic shock and resuscitation mice was weakened followed with SIRT1 and Nrf2 inhibitors. Conclusion Sevoflurane probably alleviates the oxidative reaction damage and cognitive impairment caused by cerebral reperfusion in mice through SIRT1/Nrf2/H0-1 pathway.

Hemorrhagic Shock and Resuscitation Causes Excessive Dopaminergic Signaling in the mPFC and Cognitive Dysfunction.

Peri-operative hemorrhagic shock and resuscitation (HSR), a severe traumatic stress, is closely associated with post-operative anxiety, depression, and cognitive dysfunction, subsequently causing a serious burden on families and society. Following the co-release of corticotropin-releasing factor and catecholamine, traumatic stress activates dopaminergic neurons, increasing the addictive behavior and neurocognitive impairment risks. This study investigates the association between cognitive dysfunction and dopaminergic neurons in the mPFC under HSR conditions. This study established an HSR model by bleeding and re-transfusion in the mice. After HSR exposure, a dopamine D1 receptor antagonist, SKF-83566, was administered intraperitoneally for three consecutive days. Novel object recognition (NOR), conditioned fearing (FC), and conditioned place preference (CPP) were used to assess cognitive changes 16 days after HSR exposure. Local field potential (LFP) in the mPFC was also investigated during the novel object exploration. Compared with the mice exposed to sham, there was a significant decrease in the object recognition index, a reduction in context- and tone-related freezing time, an increase in CPP values, a downregulation of ß-power but upregulation of γ-power in the mPFC in the mice exposed to HSR. Moreover, the mice exposed to HSR showed significantly upregulated TH-positive cell number, cleaved caspase-1- and TH-positive cells, and interleukin (IL)-1ß/18 expression in the mPFC compared with sham; SKF-83566 could partially reverse these alternations. The HSR caused excessive dopaminergic signaling and cognitive dysfunction in the mPFC, a condition that might be ameliorated using a dopamine D1 receptor inhibitor.

Phosphoinositide-3-Kinase/Akt-Endothelial Nitric Oxide Synthase Signaling Pathway Mediates the Neuroprotective Effect of Sevoflurane Postconditioning in a Rat Model of Hemorrhagic Shock and Resuscitation.

BACKGROUND: Although extensive reports have demonstrated the neuroprotection of sevoflurane postconditioning in cases of focal and global cerebral ischemia/reperfusion, the underlying mechanisms are not completely elucidated. This study investigated whether this effect is related to endothelial nitric oxide synthase (eNOS) and mediated by the phosphoinositide-3-kinase pathway in a rat model of hemorrhagic shock and resuscitation. METHODS: Adult male Sprague Dawley rats were subjected to hemorrhagic shock for 60 minutes and then resuscitation for 30 minutes in experimental groups. Sevoflurane postconditioning was performed at the beginning of resuscitation to completion. At 24 hours after resuscitation, the brain infarct volume was evaluated by 2,3,5-triphenyltetrazolium chloride staining. The neuronal morphological changes and apoptosis were determined by hematoxylin and eosin staining and immunohistochemistry analysis, respectively. The activity of phosphorylated Akt and eNOS was evaluated by Western blot analysis. RESULTS: Brain injuries such as the cerebral infarct volume and pathological neuronal changes as well as cell apoptosis were observed in the hippocampus after hemorrhagic shock and resuscitation. Postconditioning with 2.4% sevoflurane significantly attenuated brain injuries. Wortmannin prevented the improvements of neuronal characteristics elicited by sevoflurane postconditioning as well as the hyperactivity of eNOS and phosphorylated Akt. CONCLUSIONS: Sevoflurane postconditioning could attenuate brain injury induced by hemorrhagic shock and resuscitation, and this neuroprotective effect may be partly by upregulation of eNOS through the phosphoinositide-3-kinase/Akt signaling pathway.

The protective effects of sevoflurane postconditioning mediated by SIRTl on learning and memory impairment in liemorrhagic shock and resuscitation mice / 中国药理学通报

Aim To explore the role of the silent information regulator (silent information regulation 1, SIRTl)-mediated apoptotic pathway in the protection of sevoflurane postconditioning in hippocampal neuronal injury of mice induced by hemorrhagic shock resuscitation (HSR). Methods A mouse model of HSR was established. The male C57BL/6J mice were randomly divided into; sham operation group (Sham group), HSR group (Shock group), sevoflurane treatment group (Sevo group), sevoflurane combined with SIRTl specific inhibitor treatment group (EX527 + Sevo group) and EX527 treatment group (EX527 group). The volume of cerebral infarction was detected by TTC staining method. The changes of hippocampal nerve cells in each group of mice were detected by TUNEL staining method. The learning and memory abilities were detected by Morris water maze test. The expression of SIRTl and apoptosis-related protein levels were delected by Western blot analysis. Results The latency of the model mice reaching the platform in Morris water maze test was prolonged, while the movement distance in the target quadrant was similarly reduced. Besides, the cerebral infarction volume remarkably increased. The number of TUNEL staining positive cells increased, and the expression of SIRTl and Bel-2 decreased while the pro-apoptosis protein Bax, and cleaved-caspase 3 expression level increased; sevoflurane treatment improved nerve injury in HSR. After combined treatment with sevoflurane and SIRTl inhibitor EX527, the protective effect of sevoflurane was attenuated on nerve injury in HSR. Conclusion Sevoflurane may play a protective role against hippocampal neuronal injury caused by HSR mediated by SIRTl apoptosis-related pathway.

Sevoflurane postconditioning improves spatial learning and memory ability involving mitochondrial permeability transition pore in hemorrhagic shock and resuscitation rats.

BACKGROUND: Hemorrhagic shock induces the cognitive deficiency. Sevoflurane postconditioning has been documented to provide neuroprotection against ischemic-reperfusion injury by suppressing apoptosis. Mitochondrial permeability transition pore (mPTP) plays an important role in apoptosis, but it is unknown if the protective effect of sevoflurane postconditioning on hemorrhagic shock and resuscitation is associated with the change of mPTP opening. Hence, the aim of the study was to find out the precise mechanism of the sevoflurane postconditioning. METHODS: Sprague Dawley rats were subjected to hemorrhage shock for 60 min and then exposed to 2.4% sevoflurane for 30 min at the instant of reperfusion. Additionally, an opener (atractyloside) or an inhibitor (cyclosporine A) of mPTP was used in the animal model before sevoflurane postconditioning. Rats were randomly assigned into groups of Sham, Shock, Shock+Sevoflurane, Shock+Atractyloside, Shock+Sevoflurane+Atractyloside, Shock+Cyclosporin A, and Shock+Sevoflurane+Cyclosporin A treatment. Rat behavior was assessed for 5 days by Morris water maze 72 hr after surgery, and then hippocampus CA1 region was immunohistochemically stained. Brains were harvested 24 hr after surgery to detect the protein expression levels of Bcl-2, Bax, and cytochrome C by Western blot, the changes of mPTP opening, and mitochondrial membrane potential (MMP). RESULTS: We found that sevoflurane postconditioning significantly improved rats' spatial learning and memory ability, down-regulated the expression of Bax, cytochrome C, and caspase-3, up-regulated the expression of Bcl-2, decreased the mPTP opening, and increased the MMP. The neuroprotective effect of sevoflurane postconditioning was abolished by atractyloside, but cyclosporin A played the similar protective role as sevoflurane postconditioning. CONCLUSION: These findings proved that sevoflurane postconditioning improved spatial learning and memory ability in hemorrhage shock and resuscitation rats, the mechanism of which may be related to block mPTP opening, increase MMP, and reduce neuron apoptosis in the hippocampus.

Hydrogen gas inhalation ameliorates lung injury after hemorrhagic shock and resuscitation.

BACKGROUND: Hemorrhagic shock and resuscitation (HSR) is known to cause inflammatory reactions in the lung parenchyma and acute lung injury, increasing the risk of complications that can lead to death. Hydrogen gas has shown to inhibit the formation and eliminate reactive oxygen species (ROS), which are known to cause reperfusion injury. Hence, the purpose of this study was to investigate the protective effect of 2% inhaled hydrogen gas on post-HSR lung injury. METHODS: Rats weighing 300-500 g were divided into three groups: sham, HSR, and hydrogen (H2)/HSR groups. In the latter two groups, HSR was induced via femoral vein cannulation. Gas containing 2% hydrogen gas was inhaled only by those in the H2/HSR group. Lung tissue and abdominal aorta blood were obtained for histologic examination and arterial blood gas analyses, respectively. Neutrophil infiltration and proinflammatory mediators were also measured. RESULTS: PO2 was lower in the HSR and H2/HSR groups than in the sham group. Blood lactate level was not significantly different between the sham and H2/HSR groups, but it was significantly higher in the HSR group. Infiltration of inflammatory cells into the lung tissues was more frequent in the HSR group. Myeloperoxidase (MPO) activity was significantly different among the three groups (highest in the HSR group). All proinflammatory mediators, except IL-6, showed a significant difference among the three groups (highest in the HSR group). CONCLUSIONS: Inhalation of 2% hydrogen gas after HSR minimized the extent of lung injury by decreasing MPO activity and reducing infiltration of inflammatory cells into lung tissue.

Therapeutic effect of carbon monoxide-releasing molecule-3 on acute lung injury after hemorrhagic shock and resuscitation.

Hemorrhagic shock and resuscitation (HSR) induces a pulmonary inflammatory response and frequently causes acute lung injury. Carbon monoxide-releasing molecule-3 (CORM-3) has been reported to liberate and deliver CO under physiological conditions, which exerts organ-protective effects during systemic insults. The present study aimed to determine whether the administration of CORM-3 following HSR exerts a therapeutic effect against HSR-induced lung injury without any detrimental effects on oxygenation and hemodynamics. To induce hemorrhagic shock, rats were bled to a mean arterial blood pressure of 30 mmHg for 45 min and then resuscitated with the shed blood. CORM-3 or a vehicle was intravenously administered immediately following the completion of resuscitation. The rats were divided into four groups, including sham, HSR, HSR/CORM-3 and HSR/inactive CORM-3 groups. Arterial blood gas parameters and vital signs were recorded during HSR. The histopathological changes to the lungs were evaluated using a lung injury score, while pulmonary edema was evaluated on the basis of the protein concentration in bronchoalveolar lavage fluid and the lung wet/dry ratio. We also investigated the pulmonary expression levels of inflammatory mediators and apoptotic markers such as cleaved caspase-3 and transferase-mediated dUTP-fluorescein isothiocyanate nick-end labeling (TUNEL) staining. Although HSR caused significant lung histopathological damage and pulmonary edema, CORM-3 significantly ameliorated this damage. CORM-3 also attenuated the HSR-induced upregulation of tumor necrosis factor-α, inducible nitric oxide synthase and interleukin-1ß genes, and the expression of interleukin-1ß and macrophage inflammatory protein-2. In addition, the expression of interleukin-10, an anti-inflammatory cytokine, was inversely enhanced by CORM-3, which also reduced the number of TUNEL-positive cells and the expression of cleaved caspase-3 following HSR. Although CORM-3 was administered during the acute phase of HSR, it did not exert any influence on arterial blood gas analysis data and vital signs during HSR. Therefore, treatment with CORM-3 ameliorated HSR-induced lung injury, at least partially, through anti-inflammatory and anti-apoptotic effects, without any detrimental effects on oxygenation and hemodynamics.

Effects of sevoflurane postconditioning on oxidative stress and expression of SIRTl/PGC-1α of hippocampus in a rat model of hemorrhagic shock and resuscitation / 中国药理学通报

Aim To investigate the effects of sevoflurane postconditioning on oxidative stress and the expression of silent information regulation (SIRT1) and peroxisome proliferator-activated receptor γ coactivator la (PGC-1α) in hippocampus of rats subjected to hemorrhagic shock and resuscitation. Methods Male SD rats were randomly divided into sham surgery group (Sham group), shock and resuscitation group (Shock group) and 2.4% sevoflurane postconditioning group (Sevo group). The rats in Sevo group were inhaled 2.4% sevoflurane when received resuscitation after hemorrhagic shock, while rats in Sham and Shock group were treated with 95% O2 and 5% CO2 in the corresponding period. MAP and arterial blood gases were measured at TO (start bleeding), Tl (30 min after bleeding),T2 (start resuscitation), and T3 (30 min after resuscitation). After 24h of surgery,rats with successful model were chosen for the detection of various indexes. The content of malonaldehyde (MDA) in hippocampus and the activity of superoxide dismutase (SOD) in mitochondria isolated from hippocampal tissue were detected. Western blot was used to analyze the protein relative expression levels of SIRT1 and PGC-la in hippocampus. Results Compared with Sham group, the content of MDA increased, the activity of SOD decreased, and the expression of SIRT1 and PGC-1α a increased in Shock group (P < 0. 05). Compared with Shock group, the content of MDA decreased, the activity of SOD increased, and the expression of SIRT1 and PGC-1α increased in Sevo group (P < 0. 05). Conclusions Sevoflurane postconditioning can alleviate oxidative stress in hippocampus of a model rat of hemorrhagic shock and resuscitation, which may be correlated with the up-regulation of the protein relative expression levels of SIRT1 and PGC-1α.

Sevoflurane postconditioning improves the spatial learning and memory impairments induced by hemorrhagic shock and resuscitation through suppressing IRE1α-caspase-12-mediated endoplasmic reticulum stress pathway.

Severe hemorrhagic shock induces cognitive dysfunction by promoting cell death mediated by activating endoplasmic reticulum (ER) stress. Sevoflurane postconditioning prevents neuronal apoptosis against cerebral ischemia/reperfusion injury. It is unknown if this protective effect on hemorrhagic shock and resuscitation rats (HSR) is associated with ER stress attenuation. Male adult Sprague-Dawley rats were subjected HSR by removing 40% blood volume within 30 min, and 60 min later the animals were resuscitated with infusion of the removing blood in 30 min. Sevoflurane postconditioning was performed by inhaling sevoflurane at three different concentrations (0.5, 1.0, 1.5 MAC) at the onset of resuscitation for 30 min. Severe hypotension (mean arterial pressure 40-45 mmHg) occurred in the shock session for 60 min accompanying with significantly elevated lactate, decreased BE and pH values in arterial blood gas analysis. There were impaired spatial learning and memory following HSR indicated by persistently longer escape latency and lower correct rate, as well as less duration and crossing in the target quadrant by using Morris water maze and Y-maze tests. In the hippocampal CA1 region, there was significantly higher activity of caspase-3 induced by HSR. HSR also elevated the expression of inositol-requiring enzyme 1α (IRE1α) and caspase-12 in the hippocampus by western blot analysis. Sevoflurane postconditioning at 1.0 and 1.5 MAC significantly reversed these changes. These findings suggested that sevoflurane postconditioning could improve spatial learning and memory deficits induced by severe hemorrhagic shock and subsequent resuscitation. The suppression of endoplasmic reticulum stress provided critical contribution in neural apoptosis mediated by IRE1α-caspase-12 pathway.

The effects of pretreatment with lipo-PGE1 on expression of Caspase-3 of kidney after hemorrhagic shock and resuscitation in rats / 中华急诊医学杂志

Objective To observe the effects of pretreatment in rats with prostaglandin E1 on expression of kidney caspase-3, and TNF-α mRNA and iNOS mRNA after hemorrhagic shock and resuscitation(HSR). Method Totally 32 male S-D rots were randomly divided into four groups: group A (normal group, n=8), rats didn't receive any treatment; group B(sham, n=8), rats were pretreated with normal saline and underwent all experi-mentation procedures except bleeding; group C (HSR, n=8): rats were anesthetized with intraperitoneal sodium pentobarbital(30 mg/kg) and then subjected to hemorrhagic shock followed by resuscitation; group D (lipo-PGEl +HSR, n=8): rats were pretreated with lipo-PGEl one hour before HSR. The expressions of TNF-α mRNA and iNOS mRNA was measured by Northern blotting analysis and the expression of caspase-3 at 6 hours was determined by immunohistochemistry after HSR. Data were analyzed by ANOVA (SNK-q test), and P<0.05 was considered as significantly different. Results There were no differences in TNF-α mRNA and iNOS mRNA between normal group and sham group [(0.029±0.002) vs. (0.030±0.003),(0.029±0.002) vs. (0.030±0.003), P> 0.05]. HSR led to overexpression of caspase-3. The expression of kidney TNF-α mRNA and iNOS mRNA also increased in HSR group, compared with normal group [(0.651±0.028) vs. (0.030±0.003), (0.524±0.022) vs. (0.026±0.003), P<0.05] and sham group[(0.651±0.028) vs. (0.029±0.002), (0.524±0.022) vs. (0.025±0.003), P<0.05]. Pre-treatment with lipo-PGEl markedly reduced the expression of Caspase-3, which was consitent with decrease in expressions of TNF-α mRNA and iNOS mRNA 6 hours after HSR[(0.250± 0.019) vs. (0.651±0.028), (0.203±0.020) vs. (0.524±0.022), P<0.050]. Conclusions Lipo-PGEl could reduce the expressions of kidney Caspase-3 after HSR. The mechanisms might be attributed to inhibiting the expression of TNF-α mRNA and iNOS mRNA.