Fecal calprotectin is a novel biomarker to predict the clinical outcomes of patients with ruptured intracranial aneurysm.

BACKGROUND: Intracranial aneurysm (IA) is a common cerebrovascular disease and the leading cause of spontaneous subarachnoid hemorrhage. Recent evidence suggests that gut microbiota is involved in the pathophysiological process of IA through the gut-brain axis. However, the role of gut inflammation in the development of IA has yet to be clarified. Our study aimed to investigate whether fecal calprotectin (FC) level, a sensitive marker of gut inflammation, is correlated with the development of IA and the prognosis of patients with ruptured IA (RIA). METHODS: 182 patients were collected from January 2022 to January 2023, including 151 patients with IA and 31 healthy individuals. 151 IA patients included 109 patients with unruptured IA (UIA) and 42 patients with RIA. The FC level was measured by enzyme-linked immunosorbent assay. Other detailed information was obtained from an electronic medical record system. RESULTS: Compared with healthy controls, the FC levels in patients with IA were increased (P < 0.0001). Patients with RIA had significantly higher FC levels than UIA patients (P < 0.0001). Moreover, the FC level in RIA patients with unfavorable outcomes was higher than in RIA patients with favorable outcomes. Logistic regression analysis showed that the elevated FC level was an independent risk factor for a 3-month poor prognosis in patients with RIA (OR=1.005, 95% CI = 1.000 -1.009, P = 0.044). CONCLUSION: Fecal calprotectin level is significantly elevated in IA patients, especially those with RIA. FC is a novel biomarker of 3-month poor outcomes in RIA patients.

Knock-Down of CD24 in Astrocytes Aggravates Oxyhemoglobin-Induced Hippocampal Neuron Impairment.

Subarachnoid hemorrhage (SAH), as one of the most severe hemorrhagic strokes, is closely related to neuronal damage. Neurogenesis is a promising therapy, however, reliable targets are currently lacking. Increasing evidence has indicated that CD24 is associated with the growth of hippocampal neurons and the regulation of neural stem/precursor cell proliferation. To investigate the potential effect of CD24 in astrocytes on neuron growth in the hippocampus, we used a Transwell co-culture system of hippocampal astrocytes and neurons, and oxyhemoglobin (OxyHb) was added to the culture medium to mimic SAH in vitro. A specific lentivirus was used to knock down CD24 expression in astrocytes, which was verified by western blot, quantitative real-time polymerase chain reaction, and immunofluorescent staining. Astrocyte activation, neurite elongation, neuronal apoptosis, and cell viability were also assessed. We first determined the augmented expression level of CD24 in hippocampal astrocytes after SAH. A similar result was observed in cultured astrocytes exposed to OxyHb, and a corresponding change in SHP2/ERK was also noticed. CD24 in astrocytes was then downregulated by the lentivirus, which led to the impairment of axons and dendrites on the co-cultured neurons. Aggravated neuronal apoptosis was induced by the CD24 downregulation in astrocytes, which might be a result of a lower level of brain derived neurotrophic factor (BDNF). In conclusion, the knock-down of CD24 in astrocytes suppressed hippocampal neuron growth, in which the SHP2-ERK signaling pathway and BNDF were possibly involved.

Aucubin alleviates oxidative stress and inflammation via Nrf2-mediated signaling activity in experimental traumatic brain injury.

BACKGROUND: Aucubin (Au), an iridoid glycoside from natural plants, has antioxidative and anti-inflammatory bioactivities; however, its effects on a traumatic brain injury (TBI) model remain unknown. We explored the potential role of Au in an H2O2-induced oxidant damage in primary cortical neurons and weight-drop induced-TBI in a mouse model. METHODS: In vitro experiments, the various concentrations of Au (50 µg/ml, 100 µg/ml, or 200 µg/ml) were added in culture medium at 0 h and 6 h after neurons stimulated by H2O2 (100 µM). After exposed for 12 h, neurons were collected for western blot (WB), immunofluorescence, and M29,79-dichlorodihydrofluorescein diacetate (DCFH-DA) staining. In vivo experiments, Au (20 mg/kg or 40 mg/kg) was administrated intraperitoneally at 30 min, 12 h, 24 h, and 48 h after modeling. Brain water content, neurological deficits, and cognitive functions were measured at specific time, respectively. Cortical tissue around focal trauma was collected for WB, TdT-mediated dUTP Nick-End Labeling (TUNEL) staining, Nissl staining, quantitative real time polymerase chain reaction (q-PCR), immunofluorescence/immunohistochemistry, and enzyme linked immunosorbent assay (ELISA) at 72 h after TBI. RNA interference experiments were performed to determine the effects of nuclear factor erythroid-2 related factor 2 (Nrf2) on TBI mice with Au (40 mg/kg) treatment. Mice were intracerebroventricularly administrated with lentivirus at 72 h before TBI establishment. The cortex was obtained at 72 h after TBI and used for WB and q-PCR. RESULTS: Au enhanced the translocation of Nrf2 into the nucleus, activated antioxidant enzymes, suppressed excessive generation of reactive oxygen species (ROS), and reduced cell apoptosis both in vitro and vivo experiments. In the mice model of TBI, Au markedly attenuated brain edema, histological damages, and improved neurological and cognitive deficits. Au significantly suppressed high mobility group box 1 (HMGB1)-mediated aseptic inflammation. Nrf2 knockdown in TBI mice blunted the antioxidant and anti-inflammatory neuroprotective effects of the Au. CONCLUSIONS: Taken together, our data suggest that Au provides a neuroprotective effect in TBI mice model by inhibiting oxidative stress and inflammatory responses; the mechanisms involve triggering Nrf2-induced antioxidant system.

Peroxiredoxin 1/2 protects brain against H2O2-induced apoptosis after subarachnoid hemorrhage.

Recent studies suggest that peroxiredoxin1/2 (Prx1/2) may be involved in the pathophysiology of postischemic inflammatory responses in the brain. In this study, we assessed the distribution and function of Prx1/2 in mice after experimental subarachnoid hemorrhage (SAH). We investigated the distribution of Prx1/2 in the brains of mice both in vivo and in vitro using immunofluorescence staining. The expression of Prx1/2 after SAH was determined by Western blot. Adenanthin was used to inhibit Prx1/2 function, and Prx1/2 overexpression was achieved by injecting adeno-associated virus. Oxidative stress and neuronal apoptosis were assessed both in vivo and in vitro. The neurologic function, inflammatory response, and related cellular signals were analyzed. The results showed that Prx1 was mainly expressed in astrocytes, and Prx2 was abundant in neurons. The expression of Prx1/2 was elevated after SAH, and their expression levels peaked before proinflammatory cytokines. Inhibiting Prx1/2 promoted neuronal apoptosis by increasing the hydrogen peroxide (H2O2) levels via the apoptosis signal-regulating kinase 1/p38 pathway. By contrast, overexpression of Prx1/2 attenuated oxidative stress and neuronal apoptosis after SAH. Thus, early expression of Prx1/2 may protect the brain from oxidative damage after SAH and may provide a novel target for treating SAH.-Lu, Y., Zhang, X.-S., Zhou, X.-M., Gao, Y.-Y., Chen, C.-L., Liu, J.-P., Ye, Z.-N., Zhang, Z.-H., Wu, L.-Y., Li, W., Hang, C.-H. Peroxiredoxin 1/2 protects brain against H2O2-induced apoptosis after subarachnoid hemorrhage.

Inhibition of Elevated Hippocampal CD24 Reduces Neurogenesis in Mice With Traumatic Brain Injury.

In the adult rodents' brain, CD24 expression is restricted to immature neurons located in the neurogenesis areas. Our previous studies have confirmed that CD24 expression could be markedly elevated in the cerebral cortex after traumatic brain injury (TBI) both in humans and in mice. Although there is a close relationship between CD24 and neurogenesis, it remains unknown about the specific role of CD24 in neurogenesis areas after TBI. Here, the expression of CD24 was detected in the ipsilateral hippocampus by the Western blotting and real-time quantitative polymerase chain reaction. RNA interference was applied to investigate the effects of CD24 on post-traumatic neurogenesis. Brain sections were labeled with CD24 and doublecortin (DCX) via immunofluorescence. The Morris water maze test was used to assess cognitive functions. The results indicated that both mRNA and protein levels of CD24 were markedly elevated in the hippocampus after TBI. Meanwhile, TBI could cause a decrease of DCX-positive cells in the dentate gyrus of the hippocampus. Downregulation of CD24 significantly inhibited the phosphorylation of Src homology region 2-containing protein tyrosine phosphatase 2 in the ipsilateral hippocampus. Meanwhile, inhibition of CD24 could reduce the number of DCX-positive cells in the dentate gyrus area and impair cognitive functions of the TBI mice. These data suggested that hippocampal expression of CD24 might positively regulate neurogenesis and improve cognitive functions after TBI.

A decision tree built with parameters obtained by computed tomographic pulmonary angiography is useful for predicting adverse outcomes in non-high-risk acute pulmonary embolism patients.

BACKGROUND: Acute pulmonary embolism (APE) is one of the leading causes of death in cardiovascular disease. The 30-day mortality can still be 1.7-15% in non-high-risk APE patients. Some non-high-risk patients can progress into the high-risk group and even die, which is referred to as an adverse outcome. Promoting the diagnosis and predictive ability of adverse short-term prognosis was still a problem that needed to be solved. Computed tomography pulmonary angiography (CTPA) may be a way to promote the predictive ability. Our aim to develop predictive tools based on parameters obtained by computed tomographic pulmonary angiography (CTPA) in the form of a decision tree for use in non-high-risk acute pulmonary embolism (APE) patients. METHODS: Adverse outcome was defined within 30 days after admission to the hospital. A decision tree was built to predict adverse outcomes based on discriminating factors screened from cardiac volume and clot characteristics from recursive partitioning analysis and compared with simplified pulmonary embolism severity index (sPESI), Bova scores and risk stratification. The area under the receiver operating characteristic curve (ROC-AUC) was used to confirm the predictive ability. RESULTS: A total of 38 patients with and 303 patients without adverse outcomes were enrolled. Right ventricular/left ventricular (RV/LV) volume ratio, central pulmonary artery (CPA) embolism and right atria/left atria (RA/LA) volume ratio were used as splits in the decision tree to predict adverse outcomes in all patients. The ROC-AUC was 0.858. In CPA embolism patients, a recursive partitioning analysis was performed with cardiac volume and novel clot burden, but only the obstructing area (OA) ratio was included as a discriminating factor to build a second decision tree. The ROC-AUC for the second decision tree was 0.810. The decision trees were superior to those of sPESI, Bova scores and risk stratification, and there were no significant differences between the two decision trees. CONCLUSIONS: A decision tree built by CTPA parameters can predict adverse outcomes in non-high-risk APE patients.

The Adrenal Lipid Droplet is a New Site for Steroid Hormone Metabolism.

Steroid hormones play essential roles for living organisms. It has been long and well established that the endoplasmic reticulum (ER) and mitochondria are essential sites for steroid hormone biosynthesis because several steroidogenic enzymes are located in these organelles. The adrenal gland lipid droplet (LD) proteomes from human, macaque monkey, and rodent are analyzed, revealing that steroidogenic enzymes are also present in abundance on LDs. The enzymes found include 3ß-hydroxysteroid dehydrogenase (HSD3B) and estradiol 17ß-dehydrogenase 11 (HSD17B11). Analyses by Western blot and subcellular localization consistently demonstrate that HSD3B2 is localized on LDs. Furthermore, in vitro experiments confirm that the isolated LDs from HeLa cell stably expressing HSD3B2 or from rat adrenal glands have the capacity to convert pregnenolone to progesterone. Collectively, these data suggest that LDs may be important sites of steroid hormone metabolism. These findings may bring novel insights into the biosynthesis and metabolism of steroid hormones and the development of treatments for adrenal disorders.

Peroxiredoxin 2 activates microglia by interacting with Toll-like receptor 4 after subarachnoid hemorrhage.

BACKGROUND: Peroxiredoxin (Prx) protein family have been reported as important damage-associated molecular patterns (DAMPs) in ischemic stroke. Since peroxiredoxin 2 (Prx2) is the third most abundant protein in erythrocytes and the second most protein in the cerebrospinal fluid in traumatic brain injury and subarachnoid hemorrhage (SAH) patients, we assessed the role of extracellular Prx2 in the context of SAH. METHODS: We introduced a co-culture system of primary neurons and microglia. Prx2 was added to culture medium with oxyhemoglobin (OxyHb) to mimic SAH in vitro. Neuronal cell viability was assessed by lactate dehydrogenase (LDH) assay, and neuronal apoptosis was determined by TUNEL staining. Inflammatory factors in culture medium were measured by ELISA, and their mRNA levels in microglia were determined by qPCR. Toll-like receptor 4 knockout (TLR4-KO) mice were used to provide TLR4-KO microglia; ST-2825 was used to inhibit MyD88, and pyrrolidine dithiocarbamate (PDTC) was used to inhibit NF-κB. Related cellular signals were analyzed by Western blot. Furthermore, we detected the level of Prx2 in aneurysmal SAH patients' cerebrospinal fluids (CSF) and compared its relationship with Hunt-Hess grades. RESULTS: Prx2 interacted with TLR4 on microglia after SAH and then activated microglia through TLR4/MyD88/NF-κB signaling pathway. Pro-inflammatory factors were expressed and released, eventually caused neuronal apoptosis. The levels of Prx2 in SAH patients positively correlated with Hunt-Hess grades. CONCLUSIONS: Extracellular Prx2 in CSF after SAH is a DAMP which resulted in microglial activation via TLR4/MyD88/NF-κB pathway and then neuronal apoptosis. Prx2 in patients' CSF may be a potential indicator of brain injury and prognosis.

Estimation of right ventricular dysfunction by computed tomography pulmonary angiography: a valuable adjunct for evaluating the severity of acute pulmonary embolism.

To evaluate the feasibility and the efficacy of computed tomography pulmonary angiography (CTPA) in differentiating acute pulmonary embolism (PE) patients with or without right ventricular dysfunction and to evaluate the severity of right ventricular dysfunction in acute PE patients with CPTA. We retrospectively collected and measured the following parameters: right ventricular diameter by short axis in the axial plane (RVDaxial), left ventricular diameter by short axis in the axial plane (LVDaxial), right ventricular diameter by level on the reconstructed four-chamber views (RVD4-CH), left ventricular diameter by level on the reconstructed four-chamber views (LVD4-CH), main pulmonary artery diameter (MPAD), ascending aorta diameter (AOD), coronary sinus diameter (CSD), superior vena cava diameter (SVCD), inferior vena cava (IVC) reflux and interventricular septum deviation by CTPA, and we calculated the RVDaxial/LVDaxial, RVD4-CH/LVD4-CH and MPAD/AOD ratios in acute PE patients. We assessed right ventricular function and pulmonary artery systolic pressure (PASP) by echocardiography (ECHO) and then divided the patients into two groups: group A had right ventricular dysfunction, and group B did not have right ventricular dysfunction. We utilized a logistic regression model to analyse the relationship between right ventricular dysfunction and the measurement parameters obtained from CTPA, and we constructed the ROC curve to confirm the optimal cut-off value of the statistically significant parameter in the logistic regression model. After an initial screening, 113 acute PE patients were enrolled in our study. Among them, 42 patients showed right ventricular dysfunction (37.2 %), and 71 patients showed no right ventricular dysfunction (62.8 %). The difference between the patients with right ventricular dysfunction and patients without right ventricular dysfunction was statistical significant in RVD4-CH/LVD4-CH ratio. Logistic regression model analysis revealed that RVDaxial/LVDaxial ratio and interventricular septum deviation were correlated to right ventricular dysfunction with statistical significance (p = 0.001 and 0.03 respectively). RVDaxial/LVDaxial > 1.02 (95 % CI: 0.818-0.958, p < 0.0001, sensitivity: 90.2 %, specificity: 88.7 %) and RVD4-CH/LVD4-CH ratio > 0.999 (95 % CI 0.722-0.898, p < 0.0001) were determined as the optimal cut-off values following ROC analysis. There was a positive correlation between the MPAD/AOD ratio and PASP (r = 0.408, p = 0.01). Based on the analysis of the parameters obtained by CTPA, the RVDaxial/LVDaxial ratio and interventricular septum deviation could be utilized for predicting right ventricular dysfunction. The MPAD/AOD ratio is a potential adjunct to judge the severity of right ventricular dysfunction in acute PE.

Regenerative Neurogenesis After Ischemic Stroke Promoted by Nicotinamide Phosphoribosyltransferase-Nicotinamide Adenine Dinucleotide Cascade.

BACKGROUND AND PURPOSE: Nicotinamide adenine dinucleotide (NAD) is a ubiquitous fundamental metabolite. Nicotinamide phosphoribosyltransferase (Nampt) is the rate-limiting enzyme for mammalian NAD salvage synthesis and has been shown to protect against acute ischemic stroke. In this study, we investigated the role of Nampt-NAD cascade in brain regeneration after ischemic stroke. METHODS: Nampt transgenic (Nampt-Tg) mice and H247A mutant enzymatic-dead Nampt transgenic (ΔNampt-Tg) mice were subjected with experimental cerebral ischemia by middle cerebral artery occlusion. Activation of neural stem cells, neurogenesis, and neurological function recovery were measured. Besides, nicotinamide mononucleotide and NAD, two chemical enzymatic product of Nampt, were administrated in vivo and in vitro. RESULTS: Compared with wild-type mice, Nampt-Tg mice showed enhanced number of neural stem cells, improved neural functional recovery, increased survival rate, and accelerated body weight gain after middle cerebral artery occlusion, which were not observed in ΔNampt-Tg mice. A delayed nicotinamide mononucleotide administration for 7 days with the first dose at 12 hours post middle cerebral artery occlusion did not protect acute brain infarction and neuronal deficit; however, it still improved postischemic regenerative neurogenesis. Nicotinamide mononucleotide and NAD(+) promoted proliferation and differentiation of neural stem cells in vitro. Knockdown of NAD-dependent deacetylase sirtuin 1 (SIRT1) and SIRT2 inhibited the progrowth action of Nampt-NAD axis, whereas knockdown of SIRT1, SIRT2, and SIRT6 compromised the prodifferentiation effect of Nampt-NAD axis. CONCLUSIONS: Our data demonstrate that the Nampt-NAD cascade may act as a centralizing switch in postischemic regeneration through controlling different sirtuins and therefore represent a promising therapeutic target for long-term recovery of ischemic stroke.

Expression of Cytoplasmic Gelsolin in Rat Brain After Experimental Subarachnoid Hemorrhage.

Convincing evidence indicates that apoptosis contributes to the unfavorable prognosis of subarachnoid hemorrhage (SAH), a significant cause of morbidity and case fatality throughout the world. Gelsolin (GSN) is a Ca(2+)-dependent actin filament severing, capping, and nucleating protein, as well as multifunctional regulator of cell structure and metabolism, including apoptosis. In the present study, we intended to investigate the expression pattern and cell distribution of GSN in rat brain after experimental SAH. GSN expression was examined in sham group and at 3, 6, 12 h, day 1 (1 day), 2, 3, 5, and 7 days after SAH by Western blot analysis as well as real-time polymerase chain reaction. Immunohistochemistry and immunofluorescence were performed to detect the localization of GSN. The level of GSN protein expression was significantly decreased in SAH group and reached a bottoming point on 1 day after SAH. GSN mRNA level was significantly decreased in SAH groups in comparison with the sham group, and reached a minimum value at 12 h after SAH. Immunohistochemistry showed that GSN was constitutively and obviously expressed in the cortex of the normal rat brain and significantly decreased in the rat cortex after SAH. In addition, immunofluorescence results revealed that GSN expression could be found in both neurons and microglias, as well as in glialfibrillary acidic protein-positive astrocytes. The decreased expression of GSN could mainly be found in neurons and astrocytes as well, and GSN-positive microglias showed different cell morphological characteristics. Interestingly, the protein and gene levels of GSN seemed to be constant in the rat hippocampus of sham and SAH groups. These findings suggested a potential role of GSN in the pathophysiology of the brain at the early stage of SAH.

Tert-butylhydroquinone Ameliorates Early Brain Injury After Experimental Subarachnoid Hemorrhage in Mice by Enhancing Nrf2-Independent Autophagy.

Evidence has shown that the activation of the autophagy pathway after experimental subarachnoid hemorrhage (SAH) protects against neuronal damage. Tert-butylhydroquinone (tBHQ), a commonly used nuclear factor erythroid 2-related factor 2 (Nrf2) activator, was found to significantly enhance autophagy activation. The aim of this study was to explore the effect of tBHQ treatment on early stage brain injury at 24 h after SAH. The results showed that tBHQ treatment failed to stimulate an effective anti-oxidative effect at 24 h after the SAH operation, but succeeded in ameliorating early brain injury, including alleviated brain edema, BBB disruption, neuronal degeneration and neurological deficits. Further exploration found that tBHQ treatment significantly increased the expression of Beclin-1 and the ratio of microtubule-associated protein 1 light chain 3 (LC3)-II to LC3-I, suggesting that autophagy was enhanced after tBHQ treatment. Moreover, tBHQ treatment restored Bcl-2 and Bax expression and reduced caspase-3 cleavage, suggesting the protective effect of tBHQ treatment in ameliorating brain injury after SAH. Furthermore, tBHQ enhanced autophagy activation, decreased neuronal degeneration and improved the neurological score after SAH in Nrf2-deficient mice. Taken together, these findings suggest that tBHQ treatment exerts neuro-protective effects against EBI following SAH by enhancing Nrf2-independent autophagy. Therefore, tBHQ is a promising therapeutic agent against EBI following SAH.

ACE2 and Ang-(1-7) protect endothelial cell function and prevent early atherosclerosis by inhibiting inflammatory response.

BACKGROUND: Angiotensin-converting enzyme 2 (ACE2) is a counter-regulator against ACE by converting angiotensin II (Ang-II) to Ang-(1-7), but the effect of ACE2 and Ang-(1-7) on endothelial cell function and atherosclerotic evolution is unknown. We hypothesized that ACE2 overexpression and Ang-(1-7) may protect endothelial cell function by counterregulation of angiotensin II signaling and inhibition of inflammatory response. METHODS: We used a recombinant adenovirus vector to locally overexpress ACE2 gene (Ad-ACE2) in human endothelial cells in vitro and in apoE-deficient mice in vivo. The Ang II-induced MCP-1, VCAM-1 and E-selectin expression, endothelial cell migration and adhesion of human monocytic cells (U-937) to HUVECs by ACE2 gene transfer were evaluated in vitro. Accelerated atherosclerosis was studied in vivo, and atherosclerosis was induced in apoE-deficient mice which were divided randomly into four groups that received respectively a ACE2 gene transfer, Ad-ACE2, Ad-EGFP, Ad-ACE2 + A779, an Ang-(1-7) receptor antagonist, control group. After a gene transfer for 4 weeks, atherosclerotic pathology was evaluated. RESULTS: ACE2 gene transfer not only promoted HUVECs migration, inhibited adhesion of monocyte to HUVECs and decreased Ang II-induced MCP-1, VCAM-1 and E-selectin protein production in vitro, but also decreased the level of MCP-1, VCAM-1 and interleukin 6 and inhibit atherosclerotic plaque evolution in vivo. Further, administration of A779 increased the level of MCP-1, VCAM-1 and interleukin 6 in vivo and led to further advancements in atherosclerotic extent. CONCLUSIONS: ACE2 and Ang-(1-7) significantly inhibit early atherosclerotic lesion formation via protection of endothelial function and inhibition of inflammatory response.

SIRT1 inhibition by sirtinol aggravates brain edema after experimental subarachnoid hemorrhage.

Secondary brain injury following subarachnoid hemorrhage (SAH) is poorly understood. We utilized a rat model of SAH to investigate whether SIRT1 has a protective role against brain edema via the tumor suppressor protein p53 pathway. Experimental SAH was induced in adult male Sprague-Dawley rats by prechiasmatic cistern injection. Brain SIRT1 protein levels were examined in the sham controls and in rats 6, 12, 24, 48, and 72 hr after SAH induction. The SIRT1 inhibitor sirtinol was administered by intracerebroventricular infusion. Neurological functions, blood-brain barrier (BBB) disruption, and brain water content were assessed. Endothelial cell apoptosis, caspase 3 protein expression, p53 acetylation, and matrix metalloproteinase-9 (MMP-9) activity were examined. Compared with the control, SIRT1 protein expression increased remarkably, reaching a maximum at 24 hr after SAH. Sirtinol treatment significantly lowered SIRT1 expression, accompanied by deteriorated neurologic function, BBB disruption, brain edema, increased endothelial cell apoptosis, and increased MMP-9 gelatinase activity compared with the rats treated with vehicle only. Our results suggest that increased expression of endogenous SIRT1 may play a neuroprotective role against brain edema after SAH.

Puerarin ameliorates oxidative stress in a rodent model of traumatic brain injury.

BACKGROUND: A wealth of evidence has suggested that oxidative stress is involved in the secondary brain injury after traumatic brain injury (TBI). Recently, numerous in vivo and in vitro studies were reported that puerarin could inhibit oxidative stress through the activation of phosphatidylinositol 3-kinase (PI3K)-Akt pathway. It is unknown, however, whether puerarin can provide neuroprotection and reduce oxidative stress after TBI. The present study investigated the effects of puerarin on the TBI-induced neurodegeneration, oxidative stress, and the possible role of PI3K-Akt pathway in the neuroprotection of puerarin, in a rat model of TBI. MATERIALS AND METHODS: Rats were randomly distributed into various subgroups undergoing the sham surgery or TBI procedures. Puerarin (200 mg/kg) was given intraperitoneally at 10 min before injury and PI3K-Akt pathway inhibitor LY294002 was also administered intracerebroventricular in one subgroup. All rats were killed at 24 h after TBI for examination. RESULTS: Our data indicated that puerarin could significantly reduce TBI-induced neuronal degeneration, accompanied by the partial restoration of the redox disturbance and enhanced expression of phospho-Akt in the pericontusional cortex after TBI. Moreover, PI3K-Akt pathway inhibitor LY294002 could partially abrogate the neuroprotection of puerarin in rats with TBI. CONCLUSIONS: These results indicate that puerarin can ameliorate oxidative neurodegeneration after TBI, at least in part, through the activation of PI3K-Akt pathway.

Resveratrol prevents neuronal apoptosis in an early brain injury model.

BACKGROUND: Resveratrol has been shown to attenuate cerebral vasospasm after subarachnoid hemorrhage (SAH); however, no study has explored its neuroprotective effect in early brain injury (EBI) after experimental SAH. The aim of this study was to evaluate the antiapoptotic function of resveratrol in EBI and its relationship with the PI3K/Akt survival pathway. METHODS: Experimental SAH was induced in adult male rats by prechiasmatic cistern injection. Control and SAH rats were divided into six groups and treated with low (20 mg/kg) or high (60 mg/kg) concentrations of resveratrol with or without LY294002 cotreatment. Brain samples of the rats were analyzed by immunohistochemistry, immunofluorescence staining, Western blotting, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) apoptosis assays. RESULTS: High-concentration but not low-concentration resveratrol treatment in SAH rats led to a significant increase in phosphorylated Akt (p-Akt) protein levels compared with SAH rats without treatment. In addition, p-Akt-positive cells mainly colocalized with NeuN-positive cells. Neuronal apoptosis in SAH rat brain was attenuated by high-concentration resveratrol treatment. The antiapoptotic effect of resveratrol in SAH rats could be partially abrogated by the PI3K/Akt signaling inhibitor LY294002. CONCLUSIONS: Our results show that resveratrol has an antiapoptotic effect in EBI and that resveratrol might act through the PI3K/Akt signaling pathway.

Astaxanthin offers neuroprotection and reduces neuroinflammation in experimental subarachnoid hemorrhage.

BACKGROUND: Neuroinflammation has been proven to play a crucial role in early brain injury pathogenesis and represents a target for treatment of subarachnoid hemorrhage (SAH). Astaxanthin (ATX), a dietary carotenoid, has been shown to have powerful anti-inflammation property in various models of tissue injury. However, the potential effects of ATX on neuroinflammation in SAH remain uninvestigated. The goal of this study was to investigate the protective effects of ATX on neuroinflammation in a rat prechiasmatic cistern SAH model. METHODS: Rats were randomly distributed into multiple groups undergoing the sham surgery or SAH procedures, and ATX (25 mg/kg or 75 mg/kg) or equal volume of vehicle was given by oral gavage at 30 min after SAH. All rats were sacrificed at 24 h after SAH. Neurologic scores, brain water content, blood-brain barrier permeability, and neuronal cell death were examined. Brain inflammation was evaluated by means of expression changes in myeloperoxidase, cytokines (interleukin-1ß, tumor necrosis factor-α), adhesion molecules (intercellular adhesion molecule-1), and nuclear factor kappa B DNA-binding activity. RESULTS: Our data indicated that post-SAH treatment with high dose of ATX could significantly downregulate the increased nuclear factor kappa B activity and the expression of inflammatory cytokines and intercellular adhesion molecule-1 in both messenger RNA transcription and protein synthesis. Moreover, these beneficial effects lead to the amelioration of the secondary brain injury cascades including cerebral edema, blood-brain barrier disruption, neurological dysfunction, and neuronal degeneration. CONCLUSIONS: These results indicate that ATX treatment is neuroprotective against SAH, possibly through suppression of cerebral inflammation.

Astaxanthin alleviates early brain injury following subarachnoid hemorrhage in rats: possible involvement of Akt/bad signaling.

Apoptosis has been proven to play a crucial role in early brain injury pathogenesis and to represent a target for the treatment of subarachnoid hemorrhage (SAH). Previously, we demonstrated that astaxanthin (ATX) administration markedly reduced neuronal apoptosis in the early period after SAH. However, the underlying molecular mechanisms remain obscure. In the present study, we tried to investigate whether ATX administration is associated with the phosphatidylinositol 3-kinase-Akt (PI3K/Akt) pathway, which can play an important role in the signaling of apoptosis. Our results showed that post-SAH treatment with ATX could cause a significant increase of phosphorylated Akt and Bad levels, along with a significant decrease of cleaved caspase-3 levels in the cortex after SAH. In addition to the reduced neuronal apoptosis, treatment with ATX could also significantly reduce secondary brain injury characterized by neurological dysfunction, cerebral edema and blood-brain barrier disruption. In contrast, the PI3K/Akt inhibitor, LY294002, could partially reverse the neuroprotection of ATX in the early period after SAH by downregulating ATX-induced activation of Akt/Bad and upregulating cleaved caspase-3 levels. These results provided the evidence that ATX could attenuate apoptosis in a rat SAH model, potentially, in part, through modulating the Akt/Bad pathway.