Apoptosis In Rat Cortical Neurons Research Articles

SIRT1 Inhibits High Shear Stress-Induced Apoptosis in Rat Cortical Neurons.

Sirtuin1 (SIRT1), one of NAD+-dependent protein deacetylases, is proved to be neuroprotective in aging diseases, but its effect on neuronal apoptosis has not been clarified. To investigate the role of SIRT1 in inhibiting neuronal apoptosis, SIRT1 was interfered or overexpressed in cortical neurons. We exerted overloading laminar shear stress with 10 dyn/cm2 for 4, 8, and 12 h on neurons to cause cortical neuronal apoptosis, and the apoptosis percentage was tested by TUNEL assay. The adenovirus plasmids containing SIRT1 RNA interference or SIRT1 wild type gene were transfected into neurons before shear stress loading. SIRT1 mRNA and protein level were tested by Real-time PCR, immunofluorescence and western blots assay. SIRT1 was primarily expressed in nucleus of cortical neurons, and its mRNA level was significantly increased after 4 h stimulation. SIRT1 RNAi cortical neurons had higher TUNEL positive cells, while SIRT1 overexpression significantly decreased the percentage of died cells induced by shear stress compared to control group. SIRT1 plays a neuroprotective role in shear stress induced apoptosis and could be as potential pharmacological targets against neuronal degeneration in future.

Harpagide from Scrophularia protects rat cortical neurons from oxygen-glucose deprivation and reoxygenation-induced injury by decreasing endoplasmic reticulum stress

Ethnopharmacological relevanceHarpagide is the main ingredient in Scrophularia ningpoensis Hemsl which is used for the therapeutic purpose of treating encephalopathy. Harpagide has shown promise in the treatment of oxygen-glucose deprivation and reoxygenation (OGD/R)-induced brain injury. However, the underlying mechanisms remain unclear. Aim of studyIn this study, we aimed to determine the neuroprotective effect of harpagide on rat cortical neurons under OGD/R conditions that induce the development of ischaemia-reperfusion (I/R). Materials and methodsTo explore the biological function of harpagide in cerebral ischaemia-reperfusion injury (CIRI), The CIRI model was established by oxygen-glucose deprivation and reoxygenation (OGD/R) on rat cortical neurons. It tested cell survival rate by 3-(4,5-dimethylthiazol-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay, apoptosis by flow cytometry, intracellular Ca2+ concentration [Ca2+] i by cofocal laser, and expressions related to endoplasmic reticulum stress (ERS) by RT-PCR and Western blot. ResultsWe found that pretreatment with harpagide (50 μM) prevented OGD/R-induced apoptotic cell death. Harpagide also significantly decreased the gene expression levels and protein production of ERS-related proteins. We found that harpagide also exerted a neuroprotective effect on TG-induced apoptosis in rat cortical neurons and decreased the gene expression levels and protein production of GRP78, caspase-12 and CHOP. We also measured the intracellular calcium ion concentration ([Ca2+]i) in neurons and found that harpagide significantly decreased the [Ca2+]i induced by OGD/R and TG. ConclusionThese results suggest that harpagide protects against OGD/R-induced cell apoptosis, likely by decreasing ERS. Collectively, harpagide was demonstrated to be a prominent suppressor of ERS and prevented the apoptosis of rat cortical neurons. Based on the results, harpagide could potentially serve as a therapeutic agent of ischaemia-like injury associated with excessive ERS and apoptosis.

Anticholinergics otilonium and pinaverium trigger mitochondrial-mediated apoptosis in rat cortical neurons.

Anticholinergics otilonium and pinaverium trigger mitochondrial-mediated apoptosis in rat cortical neurons.

Role of ERK signaling pathway in inhibition of OGD/R-induced apoptosis in rat cortical neurons by sevoflurane: the relationship with mPTP

Objective To evaluate the role of extracellular signal-regulated kinase(ERK)signaling pathway in inhibition of oxygen-glucose deprivation and restoration(OGD/R)-induced apoptosis in rat cortical neurons by sevoflurane and the relationship with mitochondrial permeability transition pore(mPTP). Methods The rat cortical neurons were cultured in vitro and seeded in 6-well or 12-well culture plates.The neurons were randomly divided into 4 groups(n=18 each)using a random number table: control group(group C); OGD/R group(group O); sevoflurane group(group OS); sevoflurane+ ERK1/2 inhibitor PD98059 group(group OSP). The neurons were subjected to O2-glucose deprivation for 90 min followed by restoration of O2-glucose supply for 24 h in group O. The neurons were incubated with 2% sevoflurane for 2 h after OGD/R in group OS.OGD/R was performed at 1 h after ERK1/2 inhibitor PD98059 30 μmol/L was added, and the neurons were incubated with 2% sevoflurane for 2 h after OGD/R in group OSP.At 24 h of restoration of O2-glucose supply, the expression of phosphorylated ERK1/2(p-ERK1/2)in neurons was measured by Western blot, the neuronal apoptosis was detected using Annexin V-FITC/PI double staining combined with flow cytometry, and the opening of mPTP was determined through measuring the optical density at 540 nm.The apoptosis rate was calculated. Results Compared with group C, the expression of p-ERK1/2 in neurons was significantly up-regulated, and the apoptosis rate and mPTP opening were significantly increased in group O(P<0.05). Compared with group O, the expression of p-ERK1/2 in neurons was significantly up-regulated, and the apoptosis rate and mPTP opening were significantly decreased in group OS(P<0.05). Compared with group OS, the expression of p-ERK1/2 in neurons was significantly down-regulated, and the apoptosis rate and mPTP opening were significantly increased in group OSP(P<0.05). Conclusion The mechanism by which sevoflurane inhibits OGD/R-induced apoptosis in rat cortical neurons is related to inhibition of mPTP opening after activation of ERK signaling pathway. Key words: Extracellular signal-regulated MAP kinases; Mitochondrial membrane transport proteins; Anesthetics, inhalation; Neurons; Apoptosis

The Role of Secretory Phospholipase A2 in the Central Nervous System and Neurological Diseases

Secretory phospholipase A2 (sPLA2s) are small secreted proteins (14-18 kDa) and require submillimolar levels of Ca(2+) for liberating arachidonic acid from cell membrane lipids. In addition to the enzymatic function, sPLA2 can exert various biological responses by binding to specific receptors. Physiologically, sPLA2s play important roles on the neurotransmission in the central nervous system and the neuritogenesis in the peripheral nervous system. Pathologically, sPLA2s are involved in the neurodegenerative diseases (e.g., Alzheimer's disease) and cerebrovascular diseases (e.g., stoke). The common pathology (e.g., neuronal apoptosis) of Alzheimer's disease and stroke coexists in the mixed dementia, suggesting common pathogenic mechanisms of the two neurological diseases. Among mammalian sPLA2s, sPLA2-IB and sPLA2-IIA induce neuronal apoptosis in rat cortical neurons. The excess influx of calcium into neurons via L-type voltage-dependent Ca(2+) channels mediates the two sPLA2-induced apoptosis. The elevated concentration of intracellular calcium activates PKC, MAPK and cytosolic PLA2. Moreover, it is linked with the production of reactive oxygen species and apoptosis through activation of the superoxide producing enzyme NADPH oxidase. NADPH oxidase is involved in the neurotoxicity of amyloid β peptide, which impairs synaptic plasticity long before its deposition in the form of amyloid plaques of Alzheimer's disease. In turn, reactive oxygen species from NADPH oxidase can stimulate ERK1/2 phosphorylation and activation of cPLA2 and result in a release of arachidonic acid. sPLA2 is up-regulated in both Alzheimer's disease and cerebrovascular disease, suggesting the involvement of sPLA2 in the common pathogenic mechanisms of the two diseases. Thus, our review presents evidences for pathophysiological roles of sPLA2 in the central nervous system and neurological diseases.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) induces microglial nitric oxide production and subsequent rat primary cortical neuron apoptosis through p38/JNK MAPK pathway

It has been widely accepted that microglia, which are the innate immune cells in the brain, upon activation can cause neuronal damage. In the present study, we investigated the role of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in regulating microglial nitric oxide production and its role in causing neuronal damage. The study revealed that TCDD stimulates the expression of inducible nitric oxide synthase (iNOS) as well as the production of nitric oxide (NO) in a dose- and time-dependent manner. Further, a rapid activation of p38 and JNK MAPKs was found in HAPI microglia following TCDD treatment. Blockage of p38 and JNK kinases with their specific inhibitors, SB202190 and SP600125, significantly reduced TCDD-induced iNOS expression and NO production. In addition, it was demonstrated through treating rat primary cortical neurons with media conditioned with TCDD treated microglia that microglial iNOS activation mediates neuronal apoptosis. Lastly, it was also found that p38 and JNK MAPK inhibitors could attenuate the apoptosis of rat cortical neurons upon exposure to medium conditioned by TCDD-treated HAPI microglial cells. Based on these observations, we highlight that the p38/JNK MAPK pathways play an important role in TCDD-induced iNOS activation in rat HAPI microglia and in the subsequent induction of apoptosis in primary cortical neurons.

Cold-inducible RNA binding protein inhibits H2O2-induced apoptosis in rat cortical neurons

Objective The expression cold-inducible RNA-binding protein (CIRP) is significantly enhanced in neurons under hypothermia,but its roles remain unclear.This study aims to investigate whether the cerebral protection under hypothermia is mediated by the CIRP-mediated inhibition of neuronal apoptosis.Methods Primary rat cortical neurons were isolated,cultured,and transduced with lentiviral CIRP-RNAi.Apoptosis of the transduced neurons was induced with 100 μmol/L H2O2.The treated cells were divided into two groups,and cultured in 37℃ or 32℃ incubator respectively.Cell viability was detected by MTT colorimetric assay.Neuronal apoptosis was detected by flow cytometry after labeling the cells with Hoechst 33342 and Annexin V-FITC/PI.The protein expressions of CIRP,activated Caspase-3,and thioredoxin (TRX) were detected by Western blot.Results Under 32℃,CIRP protein was significantly induced in cortical neurons; the expression of activated Caspase-3 was decreased,while the TRX expression was increased.The rate of neuronal apoptosis was (4.5 ± 0.8) ％.Under 37 ℃,CIRP expression was evidently reduced in cortical neurons; the expression of activated caspase-3 was significantly enhanced,and TRX expression was reduced.The rate of neuronal apoptosis reaches (53.5 ± 1.7) ％ (P＜ 0.05,compared to that in 32 ℃ group).Conclusions The induction of CIRP protein in rat cortical neurons under hypothermia inhibits H2O2-induced neuronal apoptosis and thereby exerts neuroprotective effect,which forms one of the cerebral protective pathways under hypothermia. Key words: Cold-inducible RNA-binding protein; Neurons; Cerebral cortex ; Apoptosis; Hypothermia

In Vitro Activities of Kissorphin, a Novel Hexapeptide KiSS-1 Derivative, in Neuronal Cells

The primary products of the metastasis-suppressor KiSS-1 gene are the kisspeptin (KP) peptides that stimulate gonadotrophin-releasing-hormone (GnRH) release via GPR-54 receptor activation. Recent studies have suggested that the KP-10 peptide also activates neuropeptide FF (NPFF) receptors. The aim of the current study was to determine the activities of the KiSS-1 derivative kissorphin (KSO), which contains the first six amino acids of the KP-10 peptide, is C-terminally amidated, and shares amino acid similarities with the biologically active NPFF 3–8 sequence. The KSO peptide inhibited forskolin-stimulated cyclic adenosine monophosphate (cAMP) production in ND7/23 neuroblastoma cells via an action that could be inhibited by the NPFF receptor antagonist RF9. Release of GnRH by LA-N-1 neuroblastoma cells was not altered by the KSO peptide. In ND7/23 neuroblastoma cells, the KSO peptide was able to reduce forskolin neuroprotection against H2O2 toxicity. The KSO peptide was also able to prevent prostaglandin E2-induced apoptosis in rat cortical neurons. The NPFF receptor antagonist RF9 could inhibit these actions of the KSO peptide in oxidative stress and apoptosis models. In conclusion, the kissorphin peptide, comprising the amino acid sequence Tyr-Asn-Trp-Asn-Ser-Phe-NH2, has NPFF-like biological activity without showing any GnRH releasing activity and inhibits forskolin-activated cAMP release.

Cold-inducible RNA binding protein inhibits H2O2-induced apoptosis in rat cortical neurons

Objective: The expression cold-inducible RNA-binding protein (CIRP) is significantly enhanced in neurons under hypothermia, but its roles remain unclear. This study aims to investigate whether the cerebral protection under hypothermia is mediated by the CIRP-mediated inhibition of neuronal apoptosis. Methods: Primary rat cortical neurons were isolated, cultured, and transduced with lentiviral CIRP-RNAi. Apoptosis of the transduced neurons was induced with 100μmol/L H2O2, the treated cells were divided into two groups, and cultured in 37°C or 32°C incubator respectively. Cell viability was detected by MTT colorimetric assay. Neuronal apoptosis was detected by flow cytometry after labeling the cells with Hoechst 33342 and Annexin V-FITC/PI. The protein expressions of CIRP, activated caspase-3, and thioredoxin (TRX) were detected by Western blot. Results: Under 32°C, CIRP protein is significantly induced in cortical neurons; the expression of activated caspase-3 decreases, while the TRX expression increases. The rate of neuronal apoptosis is 4.5±0.8%. Under 37°C, CIRP expression is evidently reduced in cortical neurons; the expression of activated caspase-3 is significantly enhanced with reduced level of TRX expression. The rate of neuronal apoptosis reaches 53.5±1.7% (P<0.05, compared to that in 32°C group). Conclusions: The induction of CIRP protein in rat cortical neurons under hypothermia inhibits H2O2-induced neuronal apoptosis and thereby exerts neuroprotective effect, which forms one of the cerebral protective pathways under hypothermia.

Temporal relationship of autophagy and apoptosis in neurons challenged by low molecular weight β-amyloid peptide

Alzheimer's disease (AD) is an aging-related progressive neurodegenerative disorder. Previous studies suggested that various soluble Aβ species are neurotoxic and able to activate apoptosis and autophagy, the type I and type II programmed cell death, respectively. However, the sequential and functional relationships between these two cellular events remain elusive. Here we report that low molecular weight Aβ triggered cleavage of caspase 3 and poly (ADP-ribose) polymerase to cause neuronal apoptosis in rat cortical neurons. On the other hand, Aβ activated autophagy by inducing autophagic vesicle formation and autophagy related gene 12 (ATG12), and up-regulated the lysoso-mal machinery for the degradation of autophagosomes. Moreover, we demonstrated that activation of autophagy by Aβ preceded that of apoptosis, with death associated protein kinase phosphorylation as the potential molecular link. More importantly, under Aβ toxicity, neurons exhibiting high level of autophagosome formation were absent of apoptotic features, and inhibition of autophagy by 3-methylade-nine advanced neuronal apoptosis, suggesting that autophagy can protect neurons from Aβ-induced apoptosis.

Acetaminophen Induces Apoptosis in Rat Cortical Neurons

BackgroundAcetaminophen (AAP) is widely prescribed for treatment of mild pain and fever in western countries. It is generally considered a safe drug and the most frequently reported adverse effect associated with acetaminophen is hepatotoxicity, which generally occurs after acute overdose. During AAP overdose, encephalopathy might develop and contribute to morbidity and mortality. Our hypothesis is that AAP causes direct neuronal toxicity contributing to the general AAP toxicity syndrome.Methodology/Principal FindingsWe report that AAP causes direct toxicity on rat cortical neurons both in vitro and in vivo as measured by LDH release. We have found that AAP causes concentration-dependent neuronal death in vitro at concentrations (1 and 2 mM) that are reached in human plasma during AAP overdose, and that are also reached in the cerebrospinal fluid of rats for 3 hours following i.p injection of AAP doses (250 and 500 mg/Kg) that are below those required to induce acute hepatic failure in rats. AAP also increases both neuronal cytochrome P450 isoform CYP2E1 enzymatic activity and protein levels as determined by Western blot, leading to neuronal death through mitochondrial–mediated mechanisms that involve cytochrome c release and caspase 3 activation. In addition, in vivo experiments show that i.p. AAP (250 and 500 mg/Kg) injection induces neuronal death in the rat cortex as measured by TUNEL, validating the in vitro data.Conclusions/SignificanceThe data presented here establish, for the first time, a direct neurotoxic action by AAP both in vivo and in vitro in rats at doses below those required to produce hepatotoxicity and suggest that this neurotoxicity might be involved in the general toxic syndrome observed during patient APP overdose and, possibly, also when AAP doses in the upper dosing schedule are used, especially if other risk factors (moderate drinking, fasting, nutritional impairment) are present.

Secalonic acid A reduced colchicine cytotoxicity through suppression of JNK, p38 MAPKs and calcium influx

There are few articles about the cytotoxicity evoked by secalonic acid A (SAA) in some tumor cells. It has not yet been reported whether SAA has any action on neurons of the central nervous system. The aim of this study was to investigate the protective effect of SAA against apoptosis of rat cortical neurons induced by colchicine. The protective action of SAA on the cortical neurons treated with colchicine at 1 μM was examined by Hoechst 33258, LDH release and flow cytometry methods. The results from the above tests indicated that SAA at 3 and 10 μM significantly prevented colchicine-induced apoptosis of the cortical neurons. Further studies from Western blot and confocal microscopy experiments showed that the activation of JNK, p38 MAPKs and caspase-3 during neuron apoptosis triggered by 1 μM colchicine could be obviously suppressed by SAA; on the other hand, an increase in the intracellular free Ca 2+ by 1 μM colchicine in the cortical neuron was blocked evidently by SAA. The above results suggested that SAA could antagonize the cytotoxicity of colchicine in the rat cortical neurons, which may be through inhibition of phosphorylation of JNK and p38 MAPKs, calcium influx, and the activation of caspase-3.

Apocynum venetum leaf extract protects rat cortical neurons from injury induced by oxygen and glucose deprivation in vitro

This study aimed to investigate the protective effect of Apocynum venetum leaf extract (AVLE) on an in vitro model of ischemia-reperfusion induced by oxygen and glucose deprivation (OGD) and further explored the possible mechanisms underlying protection. Cell injury was assessed by morphological examination using phase-contrast microscopy and quantified by measuring the amount of lactate dehydrogenase (LDH) leakage; cell viability was measured by XTT reduction. Neuronal apoptosis was determined by flow cytometry, and electron microscopy was used to study morphological changes of neurons. Caspase-3,-8, and-9 activation and Bcl-2/Bax protein expression were determined by Western blot analysis. We report that treatment with AVLE (5 and 50µg/mL) effectively reduced neuronal cell death and relieved cell injury induced by OGD. Moreover, AVLE decreased the percentage of apoptotic neurons, relieved neuronal morphological damage, suppressed overexpression of active caspase-3 and-8 and Bax, and inhibited the reduction of Bcl-2 expression. These findings indicate that AVLE protects against OGD-induced injury by inhibiting apoptosis in rat cortical neurons by down-regulating caspase-3 activation and modulating the Bcl-2/Bax ratio.

P.2.d.017 Effect of antidepressants on apoptosis of rat cortical neurons subjected to oxygen–glucose deprivation in vitro

During puberty, attention turns away from same-sex socialization to focus on the opposite sex. How the brain mediates this change in perception and motivation is unknown. Polysialylated neural cell adhesion molecule (PSA-NCAM) virtually disappears from most of the central nervous system after embryogenesis, but it remains elevated in discrete regions of the adult brain. One such brain area is the posterodorsal subnucleus of the medial amygdala (MePD). The MePD has been implicated in male sexual attraction, measured here as the preference to investigate female odors. We hypothesize that PSA-NCAM gates hormone-dependent plasticity necessary for the emergence of males' attraction to females. To evaluate this idea, we first measured PSA-NCAM levels across puberty in several brain regions, and identified when female odor preference normally emerges in male Syrian hamsters. We found that MePD PSA-NCAM staining peaks shortly before the surge of pubertal androgen and the emergence of preference. To test the necessity of PSA-NCAM for female odor preference, we infused endo-neuraminidase-N into the MePD to deplete it of PSAs before female odor preference normally appears. This blocked female odor preference, which suggests that PSA-NCAM facilitates behaviorally relevant, hormone-driven plasticity.

Ginsenoside Rd prevents glutamate‐induced apoptosis in rat cortical neurons

1. The role of voltage-independent Ca(2+) entry in cell apoptosis has recently received considerable attention. It has been found that ginsenoside Rd significantly inhibits voltage-independent Ca(2+) entry. The aim of the present study was to investigate the protective effects of ginsenoside Rd against glutamate-induced apoptosis of rat cortical neurons. 2. Ginsenoside Rd significantly reduced glutamate-induced apoptotic morphological changes and DNA laddering. In comparison, nimodipine only had a weak effect. 3. Ginsenoside Rd (1, 3 and 10 micromol/L) concentration-dependently inhibited caspase 3 activation and expression of the p20 subunit of active caspase 3 (by 30 +/- 10%, 41 +/- 9% and 62 +/- 19%, respectively, compared with glutamate alone; P < 0.05), whereas 1 micromol/L nimodipine had no effect. 4. Glutamate decreased cell viability to 37.4 +/- 4.7 (n = 8) and evoked cell apoptosis. Ginsenoside Rd (1, 3, 10 and 30 micromol/L) concentration-dependently inhibited glutamate-induced cell death, increased cell viability and reduced apoptotic percentage (from 47.5 +/- 4.9% to 37.4 +/- 6.9%, 28.3 +/- 5.2% and 22.5 +/- 5.6%, respectively; P < 0.05). At 1 micromol/L, nimodipine had no effect on cell viability. Furthermore, although 1, 3, 10, 30 and 60 micromol/L ginsenoside Rd concentration-dependently inhibited glutamate-induced Ca(2+) entry by 8 +/- 2%, 24 +/- 4%, 40 +/- 7%, 49 +/- 8% and 50 +/- 8% (P < 0.05), respectively, nimodipine had no effect. 5. In conclusion, the results indicate that ginsenoside Rd prevents glutamate-induced apoptosis in rat cortical neurons and provide further evidence of the potential of voltage-independent Ca(2+) channel blockers as new neuroprotective drugs for the prevention of neuronal apoptosis and death induced by cerebral ischaemia.

Tanshinone IIB, a primary active constituent from Salvia miltiorrhiza, exerts neuroprotective effect via inhibition of neuronal apoptosis in vitro

Tanshinone IIB (TSB) is a major active constituent of the roots of Salvia miltiorrhiza (Danshen) widely used in the treatment of stroke and coronary heart disease in Asian countries. This study investigated the in vitro neuroprotective effects of TSB and the underlying mechanism. Co-treatment with TSB significantly inhibited the cytotoxicity and apoptosis of rat cortical neurons induced by staurosporine in a concentration-dependent manner. Consistently, TSB significantly reduced the DNA laddering caused by staurosporine in a concentration-dependent manner. TSB also suppressed the elevated Bax protein and decreased bcl-2 and caspase-3 proteins induced by staurosporine in rat cortical neurons. These findings indicated that TSB had a neuroprotective effect via inhibition of apoptosis. Further studies are warranted to investigate the role of other apoptosis-related signaling proteins and reperfusion-related mechanisms in the protective effect of TSB on neurons.

Effects of Tribulus terrestris L. saponion on apoptosis of cortical neurons induced by hypoxia-reoxygenation in rats

To observe the effects of Tribulus terrestris L. saponion (TTLS) on apoptosis in cortical neurons induced by hypoxia-reoxygenation in rats. Primary culture of rat cortical neurons was performed in vitro. A model of apoptosis of cortical neurons was established by hypoxia and reoxygenation. Hypoxia for 3 h in neural cells was induced with mixture of 95% N(2) and 5% CO(2), and then reoxygenation in neural cells was induced with mixture of 95% O(2) and 5% CO(2) for 12 h. Different concentrations of TTLS were administered to traditional Chinese herbal medicine-treated group separately during hypoxia and reoxygenation. The apoptosis rate was analyzed quantitatively by flow cytometry with Annexin V-FITC and propidium iodide staining. Mitochondria membrane potential was observed by a confocal laser-scanning microscope with JC-1 fluorescence. Caspase-3/7 activity in cytoplasm was measured by fluorescent plate reader. Bax protein expression was observed by immunohistochemical technique. The percentage of apoptosis was significantly increased, mitochondria membrane potential was obviously decreased, fluorescence of caspase-3/7 activity was increased, and Bax protein was abundantly expressed followed by 3 h of hypoxia and 12 h of reoxygenation (P<0.01). TTLS could inhibit the depression of membrane potential induced by hypoxia and reoxygenation, decrease the activity of caspase-3/7, reduce the expression of Bax protein, and inhibit the apoptosis of the cortical neurons. Hypoxia and reoxygenation can induce apoptosis of rat cortical neurons. TTLS can decrease the apoptosis induced by hypoxia and reoxygenation. The mechanism might be related to stabilization of mitochondria membrane potential, inhibition of caspase activity and reduction of Bax protein expression.

PACAP38 protects against sodium nitroprusside-induced apoptosis in rat cortical neurons

PACAP38 protects against sodium nitroprusside-induced apoptosis in rat cortical neurons

PACAP38 protects against sodium nitroprusside‐induced apoptosis in rat cortical neurons

PACAP38 protects against sodium nitroprusside‐induced apoptosis in rat cortical neurons

Street heroin induces mitochondrial dysfunction and apoptosis in rat cortical neurons

Cortical function has been suggested to be highly compromised by repeated heroin self-administration. We have previously shown that street heroin induces apoptosis in neuronal-like PC12 cells. Thus, we analysed the apoptotic pathways involved in street heroin neurotoxicity using primary cultures of rat cortical neurons. Our street heroin sample was shown to be mainly composed by heroin, 6-monoacetylmorphine and morphine. Exposure of cortical neurons to street heroin induced a slight decrease in metabolic viability, without loss of neuronal integrity. Early activation of caspases involved in the mitochondrial apoptotic pathway was observed, culminating in caspase 3 activation, Poly-ADP Ribose Polymerase (PARP) cleavage and DNA fragmentation. Apoptotic morphology was completely prevented by the non-selective caspase inhibitor z-VAD-fmk, indicating an important role for caspases in neurodegeneration induced by street heroin. Ionotropic glutamate receptors, opioid receptors and oxidative stress were not involved in caspase 3 activation. Interestingly, street heroin cytotoxicity was shown to be independent of a functional mitochondrial respiratory chain, as determined using NT-2 rho(0) cells. Nonetheless, in street heroin-treated cortical neurons, cytochrome c was released, accompanied by a decrease in mitochondrial potential and Bcl-2/Bax. Pure heroin hydrochloride similarly decreased metabolic viability but only slightly activated caspase 3. Altogether, our data suggest an important role for mitochondria in mediating street heroin neurotoxic effects.