The protection of Bcl-2 overexpression on rat cortical neuronal injury caused by analogous ischemia/reperfusion in vitro

The role of sex and ovarian hormones in hippocampal damage and cognitive deficits induced by chronic exposure to hypobaric hypoxia

Purpose

This study aims to investigate the role of sex and ovarian hormones in hippocampal damage and cognitive deficits and behavioral dysfunction in rats induced by chronic exposure to hypobaric hypoxia.

Methods

Six-week-old male and female SD rats were housed for 3 months either in a real altitude (4,250 m) environment as the model of chronic hypobaric-hypoxia (CHH) or in a plain as controls. The animal behavioral and hippocampal neurons at subcellular, molecular, and ultrastructural levels were characterized after CHH exposure.

Results

After 3 months of CHH exposure, (1) male CHH rats’ serum testosterone level was lower than male controls’ whereas female CHH rats’ serum estradiol level was higher than female controls’; (2) Morris water maze test finds that male rats showed more learning and spatial memory deficits than female rats; (3) male rats showed more severe hippocampal damage, hippocampal inflammation, oxidative stress and decreased hippocampal integrity (neurogenesis and dendritic spine density) than female rats; (4) Western blot analysis shows that, compared with the male control group, in male CHH group’s hippocampus, expression of nNOS, HO-1, and Bax protein increased whereas that of Bcl-2 protein decreased; (5) Expression of PON2 protein in male rats (CHH and controls) was lower than female rats (CHH and controls). In addition, CHH exposure decreased the expression of PON2 protein in both male and female rats; (6) qPCR analysis reveals that CHH exposure reduced the gene expression of N-methyl-D-aspartate receptor NR2A and NR2B subunits in male rats’ hippocampus. In addition, compared with the sham CHH group, the expression level of PON2 protein decreased in the OVX-CHH group’s hippocampus whereas oxidative stress, neuroinflammation, and degeneration of hippocampal neurons increased in the OVX-CHH group’s hippocampus.

Conclusion

After CHH exposure, male rats were significantly more likely than female rats to develop hippocampal damage, hippocampal neuroinflammation, and cognitive decline and deficits, suggesting that sex and ovarian hormones were significantly involved in regulating the rats’ susceptibility to CHH exposure-induced hippocampal damage.

Taurine Ameliorates Iron Overload-Induced Hepatocyte Injury via the Bcl-2/VDAC1-Mediated Mitochondrial Apoptosis Pathway

Iron overload can induce reactive oxygen species (ROS) burst and liver damage. Taurine can reduce ROS production and ameliorate liver injury caused by iron overload; however, the underlying molecular mechanism remains elusive. Herein, L02 cells treated with 120 μM iron dextran for 48 h showed marked oxidative stress damage and significantly increased apoptosis. Taurine protected hepatocytes by stabilizing mitochondrial membranes and resisting oxidative stress damage caused by iron overload. However, transfection with siRNA Bcl-2 virus abrogated the observed protective effects. Following treatment with taurine, B cell lymphoma-2 (Bcl-2) could inhibit the opening of the mitochondrial permeability transition pore (mPTP), subsequently stabilizing the mitochondrial membrane potential by interacting with voltage-dependent anion channel 1 (VDAC1) of mPTP. The present study is the first to clarify the mechanism underlying taurine-afforded hepatocyte protection against iron overload-induced oxidative stress via Bcl-2-mediated inhibition of mPTP opening and the antiapoptotic pathway.

Ecto-5'-nucleotidase (CD73) inhibits dorsal root ganglion neuronal apoptosis by promoting the Ado/cAMP/PKA/CREB pathway

Spinal cord injury (SCI) is a serious affliction that can lead to insufficient blood supply to the spinal cord, resulting in nutrient and energy deficiency in nerve cells such as neurons. In the present study, a spinal cord injury mouse model was constructed using wild-type (WT) and ecto-5'-nucleotidase (CD73)^-/- mice. The results of TUNEL and immunofluorescence assays indicated that the apoptosis of neurons in CD73^-/- mice was increased after spinal cord injury. Dorsal root ganglion (DRG) neurons from WT and CD73^-/- mice were cultured in low glucose and hypoxic conditions to simulate the effects of spinal cord injury on neurons. Subsequently, a western blot assay was used to detect the expression of CD73, caspase-3 and Bcl-2. Flow cytometry was used to detect cell apoptosis and the corresponding kits were used to detect changes in lactate dehydrogenase (LDH), superoxide dismutase (SOD), malondialdehyde (MDA), reactive oxygen species (ROS), adenosine triphosphate (ATP) and cell activity. The results revealed that the apoptosis level of CD73-overexpressing DRG neurons was decreased under anoxia and glucose deficiency. The release of LDH, MDA and the production of ROS in CD73 DRG neurons was decreased, while the synthesis of ATP, the activity of SOD and cell activity increased after hypoxia-hypoglycemia treatment. Additional cellular studies demonstrated that blocking the expression and hydrolase activity of CD73 with α,β-methylene ADP (APCP) could counteract the protective effect of CD73 on neuronal apoptosis, while adenosine (Ado) could rescue the increased apoptosis caused by CD73 deletion. In addition, the cAMP/ protein kinase A (PKA)/cAMP response element-binding protein (CREB) signaling pathway was also positively regulated by CD73 and Ado. In conclusion, CD73 could inhibit DRG neuronal apoptosis by promoting the Ado/cAMP/PKA/CREB pathway.

Flavonoids as key bioactive components of Oxytropis falcata bunge, a traditional anti-inflammatory and analgesic Tibetan medicine

The traditional Tibetan medicine Oxytropis falcata Bunge, in the Leguminosae family, is widely used in the west area owing to its significant anti-inflammatory and analgesic activities. O. falcata is rich in flavonoids, which are the main secondary metabolites and key bioactive components of this plant. Up to now, 91 flavonoids have been isolated from O. falcata, including isoflavone, flavone, flavonone, flavonol, homoisoflavonoid, chalcone, dihydrochalcone, chalcone dimers, and pterocarpans. The flavonoids in O. falcata have good anti-inflammatory and analgesic activities, which are comparable to those of a positive drug control (indomethacin). Furthermore, these flavonoids exhibit antibacterial, antioxidant, antitumour, anti-cardiovascular disease, and haemostatic activities. However, to date, O. falcata has not been reviewed comprehensively. Herein, the main secondary metabolites, biosynthetic pathways, and bioactivities of O. falcata are discussed.

Neuroprotective Effects of Purple Sweet Potato Balinese Cultivar in Wistar Rats With Ischemic Stroke

BACKGROUND:

Purple sweet potato (Ipomoea Batatas L.) is one of the sources for anthocyanin, which promotes the health through antioxidant, anti-inflammatory, anti-cancer, neuroprotection, and anti-apoptosis activities. Oxidative stress has been shown to be the cause of apoptosis in ischemic stroke.

AIM:

The objective of this research was to delineate the pleiotropic effects of anthocyanin for neuroprotection during an acute stroke event.

METHODS:

Anthocyanin was extracted from Balinese cultivar of purple sweet potato and subsequently administered to rat models of induced ischemic stroke (labelled as treatment group), as well as a placebo (labelled as a control group). Several parameters were in turn evaluated, i.e. the activities of anti-apoptotic (Bcl-2) as well as pro-apoptotic (cytochrome c, caspase-3) molecules, and apoptosis rate. Bcl-2 levels were determined using the histochemical method, cytochrome c and caspase-3 via ELISA method, while apoptosis rate was measured by TdT-medicated Dutp-Nick End Labeling (TUNEL) assay.

RESULTS:

Bcl-2 expression demonstrated significantly higher Bcl-2 expression in the treatment compared with control group (median 31.2 vs. 1.1; p = 0.001). Accordingly, pro-apoptotic cytochrome c and caspase-3 levels were also found significantly lower in the treatment as opposed to control group (mean 4.17 vs. 8.06; p = 0.001; mean 3.81 vs. 8.02; p = 0.001). Ultimately, apoptosis rate was found markedly lower among treatment than control groups (mean 3.81 vs. control 21.97; p = 0.003).

CONCLUSION:

The results of this study indicated a significant neuroprotective effect of anthocyanin derived from Balinese cultivar of PSP. Anthocyanin was able to increase and reduce anti-apoptotic and pro-apoptotic protein levels, respectively, resulting in lesser cellular apoptotic rate when compared with placebo. The potential mechanism was thought mainly due to its anti-oxidant properties.

Physiological and Biological Responses to Short-Term Intermittent Hypobaric Hypoxia Exposure: From Sports and Mountain Medicine to New Biomedical Applications

In recent years, the altitude acclimatization responses elicited by short-term intermittent exposure to hypoxia have been subject to renewed attention. The main goal of short-term intermittent hypobaric hypoxia exposure programs was originally to improve the aerobic capacity of athletes or to accelerate the altitude acclimatization response in alpinists, since such programs induce an increase in erythrocyte mass. Several model programs of intermittent exposure to hypoxia have presented efficiency with respect to this goal, without any of the inconveniences or negative consequences associated with permanent stays at moderate or high altitudes. Artificial intermittent exposure to normobaric hypoxia systems have seen a rapid rise in popularity among recreational and professional athletes, not only due to their unbeatable cost/efficiency ratio, but also because they help prevent common inconveniences associated with high-altitude stays such as social isolation, nutritional limitations, and other minor health and comfort-related annoyances. Today, intermittent exposure to hypobaric hypoxia is known to elicit other physiological response types in several organs and body systems. These responses range from alterations in the ventilatory pattern to modulation of the mitochondrial function. The central role played by hypoxia-inducible factor (HIF) in activating a signaling molecular cascade after hypoxia exposure is well known. Among these targets, several growth factors that upregulate the capillary bed by inducing angiogenesis and promoting oxidative metabolism merit special attention. Applying intermittent hypobaric hypoxia to promote the action of some molecules, such as angiogenic factors, could improve repair and recovery in many tissue types. This article uses a comprehensive approach to examine data obtained in recent years. We consider evidence collected from different tissues, including myocardial capillarization, skeletal muscle fiber types and fiber size changes induced by intermittent hypoxia exposure, and discuss the evidence that points to beneficial interventions in applied fields such as sport science. Short-term intermittent hypoxia may not only be useful for healthy people, but could also be considered a promising tool to be applied, with due caution, to some pathophysiological states.

Downregulation of TRB3 protects neurons against apoptosis induced by global cerebral ischemia and reperfusion injury in rats

Global cerebral ischemia and reperfusion injury (GCI/R) can lead to neuronal apoptosis and contributes to permanent neurological sequelae. However, the underlying mechanism is largely unknown. Therefore, the present study aimed to assess the effects of GCI/R on the tribbles homolog 3 (TRB3) and to explore the role of TRB3 in GCI/R. The GCI/R model was developed in Sprague-Dawley male rats by four-vessel occlusion. Subsequently, the expressions of TRB3, endoplasmic reticulum stress markers, and apoptosis-associated proteins were examined by western blot at 1h, 6h, 12h, 24h, and 72h after GCI/R. TRB3 short-hairpin RNA (shRNA) lentivirus was constructed and used to investigate the role of TRB3 in GCI/R-induced neuronal apoptosis. GCI/R increased the level of TRB3, endoplasmic reticulum stress markers, and pro-apoptotic proteins. The level of protein kinase B (Akt) phosphorylation was reduced during GCI/R. Administration of TRB3 shRNA lentivirus attenuated GCI/R-induced up-regulation of TRB3, endoplasmic reticulum stress, and neuronal apoptosis. Furthermore, TRB3 shRNA lentivirus reversed the reduced level of Akt phosphorylation induced by GCI/R. These data implied that TRB3 participated in the GCI/R-induced neuronal apoptosis. Knocking down TRB3 attenuated endoplasmic reticulum stress, enhanced Akt phosphorylation, and protected neurons from apoptosis in response to GCI/R. These results demonstrated that the downregulation of TRB3 may be a promising approach for treating GCI/R.

Acetaminophen attenuates lipopolysaccharide-induced cognitive impairment through antioxidant activity

Background

Considerable evidence has shown that neuroinflammation and oxidative stress play an important role in the pathophysiology of postoperative cognitive dysfunction (POCD) and other progressive neurodegenerative disorders. Increasing evidence suggests that acetaminophen (APAP) has unappreciated antioxidant and anti-inflammatory properties. However, the impact of APAP on the cognitive sequelae of inflammatory and oxidative stress is unknown. The objective of this study is to explore whether APAP could have neuroprotective effects on lipopolysaccharide (LPS)-induced cognitive impairment in mice.

Methods

A mouse model of LPS-induced cognitive impairment was established to evaluate the neuroprotective effects of APAP against LPS-induced cognitive impairment. Adult C57BL/6 mice were treated with APAP half an hour prior to intracerebroventricular microinjection of LPS and every day thereafter, until the end of the study period. The Morris water maze was used to assess cognitive function from postinjection days 1 to 3. Animal behavioural tests as well as pathological and biochemical assays were performed to evaluate LPS-induced hippocampal damage and the neuroprotective effect of APAP.

Results

Mice treated with LPS exhibited impaired performance in the Morris water maze without changing spontaneous locomotor activity, which was ameliorated by treatment with APAP. APAP suppressed the accumulation of pro-inflammatory cytokines and microglial activation induced by LPS in the hippocampus. In addition, APAP increased SOD activity, reduced MDA levels, modulated glycogen synthase kinase 3β (GSK3β) activity and elevated brain-derived neurotrophic factor (BDNF) expression in the hippocampus. Moreover, APAP significantly decreased the Bax/Bcl-2 ratio and neuron apoptosis in the hippocampus of LPS-treated mice.

Conclusions

Our results suggest that APAP may possess a neuroprotective effect against LPS-induced cognitive impairment and inflammatory and oxidative stress via mechanisms involving its antioxidant and anti-inflammatory properties, as well as its ability to inhibit the mitochondrial permeability transition (MPT) pore and the subsequent apoptotic pathway.

[Effects of umbilical cord blood mononuclear cells transplantation via lateral ventricle on the neural apoptosis and the expression of Bax and Bcl-2 proteins in neonatal rats with hypoxic-ischemic brain damage]

OBJECTIVE

To explore the effects of umbilical cord blood mononuclear cells (UCBMC) transplantation on the neuronal apoptosis and the expression of Bcl-2 and Bax proteins in neonatal rats with hypoxic-ischemic brain damage (HIBD).

METHODS

Seven-day-old Sprague-Dawley neonatal rats were randomly divided into normal control (N)+normal saline (NS), HIBD+NS, N+UCBMC, and HIBD+UCBMC groups. HIBD model was prepared using the classical Rice-Vannucci method. Twenty-four hours after HIBD, UCBMC were transplanted in the N+UCBMC and HIBD+UCBMC groups. Seven days after transplantation, NeuN/Cleaved-Caspase-3 double immunofluorescence staining and TUNEL methods were used to observe neural apoptosis in the cortex. The expression levels of Bax and Bcl-2 proteins were examined by Western blot analysis.

RESULTS

There were more NeuN⁺ cleaved Caspase-3⁺DAPI⁺ and TUNEL⁺DAPI⁺ cells in the HIBD+NS group compared with the N+NS and N+UCBMC groups (P<0.01). There were less NeuN⁺ cleaved Caspase-3⁺DAPI⁺ and TUNEL⁺DAPI⁺ cells in the HIBD+UCBMC group compared with the HIBD+NS group (P<0.01). The concentration of Bax protein was higher and that of Bcl-2 proteins was lower in the HIBD+NS group compared with the N+NS and N+UCBMC groups (P<0.01). The concentration of Bax protein in HIBD+UCBMC group was lower than that in the HIBD+NS group (P<0.01). The concentration of Bcl-2 protein was higher compared with the HIBD+NS, N+NS and N+UCBMC groups (P<0.05).

CONCLUSIONS

UCBMC transplantation via lateral ventricle can upregulate the expression of Bcl-2 protein and down-regulate the expression of Bax protein, thus alleviating brain neural apoptosis in neonatal rats with HIBD.

Traditional Chinese medicine targeting apoptotic mechanisms for esophageal cancer therapy

Esophageal cancer is one of the most common types of cancer in the world, and it demonstrates a distinct geographical distribution pattern in China. In the last decade, inducing apoptosis with traditional Chinese medicine (TCM) has become an active area in both fundamental and clinical research on cancer therapy. In this review, we summarize the molecular mechanisms by which TCM induces apoptosis in esophageal cancer cells. These mechanisms are generally related but not limited to targeting the extrinsic death receptor pathway, the intrinsic mitochondrial pathway, and the endoplasmic reticulum (ER) stress pathway. By using different monomers and composite prescriptions of TCM, it is possible to modulate the ratio of Bcl-2/Bax, regulate the expression of caspase proteases and mitochondrial transmembrane potential, increase the expression of Fas and p53, down-regulate NF-κB pathway and the expression of Chop and survivin, and block cell cycle progression.

miR-135a inhibition protects A549 cells from LPS-induced apoptosis by targeting Bcl-2

Acute lung injury (ALI) is a severe clinical condition with high morbidity and mortality. Apoptosis is a key pathologic feature of ALI, and Bcl-2 plays an important role during the pathogenesis of ALI via the regulation of apoptosis. However, the regulation of Bcl-2 during ALI, particularly through microRNAs, remains unclear. We hypothesize that certain miRNAs may play deleterious or protective roles in ALI via the regulation of Bcl-2. The LPS stimulation of A549 cells was used to mimic ALI in vitro. First, we confirmed that Bcl-2 is involved in LPS-induced apoptosis in A549 cells. Then, bioinformatic analyses and quantitative real-time polymerase chain reaction assays were performed to screen for miRNAs targeting Bcl-2. We observed that miR-135a was markedly increased in LPS-challenged A549 cells. miR-135a inhibition markedly restored Bcl-2 expression and protected A549 cells from LPS-induced apoptosis. Furthermore, bioinformatic analysis and luciferase activity assays were conducted to confirm that miR-135a binds directly to the 3'-untranslated region of Bcl-2 and suppresses its expression. Interestingly, the inhibition of miR-135a did not attenuate apoptosis under LPS-treated conditions when Bcl-2 was knocked down. Therefore, we suggest that miR-135a regulation of LPS-induced apoptosis in A549 cells may depend in part on the regulation of Bcl-2. The miR-135a/Bcl-2 signaling pathway may be a novel therapeutic target for the prevention of ALI.

Neuroprotective effect of TAT PTD-Ngb fusion protein on primary cortical neurons against hypoxia-induced apoptosis

Hypoxic-ischemic injury increases neuroglobin (Ngb) expression in the brain. In our previous study, we have generated a transactivator-of-transcription protein-transduction domain-neuroglobin fusion protein (TAT PTD-Ngb) that successfully mediated exogenous Ngb expression in the primary neurons. In this study, we further investigated the role of TAT PTD-Ngb in protecting neurons against hypoxia-induced apoptosis and explored the possible mechanism. The primary cultured neurons were divided into four groups: (1) the normal group (no hypoxic injury); (2) the vehicle group (vehicle treatment and hypoxia injury); (3) the TAT PTD-Ngb group (TAT PTD-Ngb treatment and hypoxia injury); and (4) the Ngb group (Ngb treatment and hypoxia injury). Translocation of TAT PTD-Ngb into neurons was detected using fluorescent immunostaining against His-tag as early as 30 min after incubation. MTT assay showed that the TAT PTD-Ngb group had significantly increased cell viability compared to the vehicle or Ngb group after hypoxia. The result of transmission electron microscopy (TEM) also displayed rescued ultrastructure in TAT PTD-Ngb neurons compared to that of apoptotic neurons. In addition, TAT PTD-Ngb neurons showed significantly increased expression of anti-apoptotic Bcl-2 protein and decreased activities of caspase-3 and caspase-9 in response to hypoxia. These results suggest that TAT PTD-Ngb fusion protein protects primary cortical neurons against hypoxia-induced injury possibly through suppressing mitochondria apoptotic pathway.

Pharmacological postconditioning with diazoxide attenuates ischemia/reperfusion-induced injury in rat liver

It has been demonstrated that ischemic postconditioning (IPO) is capable of attenuating ischemia/reperfusion (I/R) injury in the heart. However, the novel role of pharmacological postconditioning in the liver remains unclear. In this study, the hypothesis that diazoxide postconditioning reduces I/R-induced injury in rat liver was tested. Rats were assigned randomly to the sham-operated control, I/R (occlusion of the porta hepatis for 60 min, followed by a persistent reperfusion for 120 min), diazoxide ischemic postconditioning (DIPO; occlusion of the porta hepatis for 60 min, then treatment with diazoxide for 10 min reperfusion, followed by a persistent reperfusion for 110 min) or 5-hydroxydecanoate (5-HD)+DIPO (occlusion of the porta hepatis for 60 min, then treatment with diazoxide and 5-HD for 10 min reperfusion, followed by a persistent reperfusion for 110 min) groups. The alanine aminotransferase (ALT) and aspartate transaminase (AST) levels were assayed. The expression levels of protein kinase c-ε (pkc-ε), cytochrome c (cyt-c), caspase-3 and bcl-2 protein were determined by western blotting. The serum levels of ALT and AST and expression levels of cyt-c and caspase-3 were significantly lower in the DIPO group (P<0.05). However, the protein expression levels of pkc-ε and bcl-2 were markedly increased in the DIPO group (P<0.05). 5-HD abrogated the protective effects of DIPO. The data of the present study provide the first evidence that DIPO protects the liver from I/R injury by opening the mitochondrial K_ATP channels, activating and upregulating pkc-ε and inhibiting the activation of the apoptotic pathway by decreasing the release of cyt-c and the expression of caspase-3 and increasing bcl-2 expression.

Targeting C/EBP homologous protein with siRNA attenuates cerebral vasospasm after experimental subarachnoid hemorrhage

Endothelial apoptosis plays a major role in the development of cerebral vascular spasm after subarachnoid hemorrhage (SAH). C/EBP homologous protein (CHOP) orchestrates apoptosis in a variety of cell types in response to endoplasmic reticulum (ER) stress, implicated in the brain injury after SAH. However, the role of CHOP in the mechanism of cerebral vasospasm (CVS) after SAH remains unexplored. The aim of this study was to evaluate the effect of CHOP silencing on endothelial apoptosis and CVS following subarachnoid hemorrhage in the rat. The study was conducted on 65 rats and employed endovascular perforation model of SAH. CHOP siRNAs were injected 24 h prior to the hemorrhage. At 72 h after SAH brains with basilar arteries (BA) were collected from euthanized rats for laboratory investigations. Triple fluorescence stain revealed expression of CHOP in cerebral vascular endothelia after SAH. Marked reduction of CHOP protein and the reduction of its downstream signaling effectors, bim and caspase-3, were found in BA with Western blot analysis. CHOP silencing reduced number of apoptotic endothelial cells in BA, and increased BA diameter after SAH. The amelioration of CVS was associated with reduced neuronal injury in cerebral tissues. In conclusion, CHOP siRNA treatment can effectively combat apoptotic mechanisms of cerebral vasospasm set in motion by subarachnoid bleeding.

Amyloid β-induced ER stress is enhanced under mitochondrial dysfunction conditions

Previously we reported that endoplasmic reticulum (ER)-mitochondria crosstalk is involved in amyloid-β (Aβ)-induced apoptosis. Now we show that mitochondrial dysfunction affects the ER stress response triggered by Aβ using cybrids that recreate the defect in mitochondrial cytochrome c oxidase (COX) activity detected in platelets from Alzheimer's disease (AD) patients. AD and control cybrids were treated with Aβ or classical ER stressors and the ER stress-mediated apoptotic cell death pathway was accessed. Upon treatment, we found increased glucose-regulated protein 78 (GRP78) levels and caspase-4 activation (ER stress markers) which were more pronounced in AD cybrids. Treated AD cybrids also exhibited decreased cell survival as well as increased caspase-3-like activity, poli-ADP-ribose-polymerase (PARP) levels and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive apoptotic cells. Finally, we showed that Aβ-induced caspase-3 activation in both cybrid cell lines was prevented by dantrolene, thus implicating ER Ca(2+) release in ER stress-mediated apoptosis. Our results demonstrate that mitochondrial dysfunction occurring in AD patients due to COX inhibition potentiates cell susceptibility to Aβ-induced ER stress. This study further supports the close communication between ER and mitochondria during apoptosis in AD.

Ischemia induces endoplasmic reticulum stress and cell apoptosis in human brain

In animal models, endoplasmic reticulum (ER) stress and apoptosis take place around cerebral infarction areas during ischemia, which presumably protect tissues from necroses-induced injury as well as promote cells toward death. We examined whether these pathological changes, especially temporal occurrence, were present in patients who suffered from cerebral ischemia. The studies by immunohistochemistry show that ER chaperone glucose-regulated protein (GRP78) and caspase-9 elevate around infarction areas. The experiments by terminal deoxynucleotidy transferase-mediated 2'-deoxyuridine 5'-triphosphate-biotin nick-end labeling (TUNEL) illustrate that TUNEL-positive cells are higher around infarction tissues than controls. Moreover, GRP78, caspase-9 and TUNEL cells emerge one after another during ischemia. In conclusion, ER stress, apoptosis initiation and DNA fragment develop sequentially in ischemic human brain. ER stress during excessive ischemia stimulates apoptotic cell death beyond activating a defense for nerve cells being away from injury.

Acetaminophen reduces mitochondrial dysfunction during early cerebral postischemic reperfusion in rats

Acetaminophen, a popular analgesic and antipyretic, has been found to be effective against neuronal cell death in in vivo and in vitro models of neurological disorders. Acute neuronal death has been attributed to loss of mitochondrial permeability transition coupled with mitochondrial dysfunction. The potential impact of acetaminophen on acute injury from cerebral ischemia-reperfusion has not been studied. We investigated the effects of acetaminophen on cerebral ischemia-reperfusion-induced injury using a transient global forebrain ischemia model. Male Sprague-Dawley rats received 15mg/kg of acetaminophen intravenously during ischemia induced by hypovolemic hypotension and bilateral common carotid arterial occlusion, which was followed by reperfusion. Acetaminophen reduced tissue damage, degree of mitochondrial swelling, and loss of mitochondrial membrane potential. Acetaminophen maintained mitochondrial cytochrome c content and reduced activation of caspase-9 and incidence of apoptosis. Our data show that acetaminophen reduces apoptosis via a mitochondrial-mediated mechanism in an in vivo model of cerebral ischemia-reperfusion. These findings suggest a novel role for acetaminophen as a potential stroke therapeutic.