Oxidative stress induces mitochondrial iron overload and ferroptotic cell death.

Oxidative stress has been shown to induce cell death in a wide range of human diseases including cardiac ischemia/reperfusion injury, drug induced cardiotoxicity, and heart failure. However, the mechanism of cell death induced by oxidative stress remains incompletely understood. Here we provide new evidence that oxidative stress primarily induces ferroptosis, but not apoptosis, necroptosis, or mitochondria-mediated necrosis, in cardiomyocytes. Intriguingly, oxidative stress induced by organic oxidants such as tert-butyl hydroperoxide (tBHP) and cumene hydroperoxide (CHP), but not hydrogen peroxide (H2O2), promoted glutathione depletion and glutathione peroxidase 4 (GPX4) degradation in cardiomyocytes, leading to increased lipid peroxidation. Moreover, elevated oxidative stress is also linked to labile iron overload through downregulation of the transcription suppressor BTB and CNC homology 1 (Bach1), upregulation of heme oxygenase 1 (HO-1) expression, and enhanced iron release via heme degradation. Strikingly, oxidative stress also promoted HO-1 translocation to mitochondria, leading to mitochondrial iron overload and lipid reactive oxygen species (ROS) accumulation. Targeted inhibition of mitochondrial iron overload or ROS accumulation, by overexpressing mitochondrial ferritin (FTMT) or mitochondrial catalase (mCAT), respectively, markedly inhibited oxidative stress-induced ferroptosis. The levels of mitochondrial iron and lipid peroxides were also markedly increased in cardiomyocytes subjected to simulated ischemia and reperfusion (sI/R) or the chemotherapeutic agent doxorubicin (DOX). Overexpressing FTMT or mCAT effectively prevented cardiomyocyte death induced by sI/R or DOX. Taken together, oxidative stress induced by organic oxidants but not H2O2 primarily triggers ferroptotic cell death in cardiomyocyte through GPX4 and Bach1/HO-1 dependent mechanisms. Our results also reveal mitochondrial iron overload via HO-1 mitochondrial translocation as a key mechanism as well as a potential molecular target for oxidative stress-induced ferroptosis in cardiomyocytes.

Melatonin Protects Against Titanium Oxide-Induced Neurotoxicity: Neurochemical, Neurobehavioral, and Histopathological Evidences.

titania (titanium dioxide, TiO2) is known to induce neurotoxicity and CNS dysfunctions. Numerous studies have explored the neuroprotective effects of melatonin against neurotoxicity. This study evaluates the potential of melatonin to protect against titania-induced neurotoxicity and the role of the Keap1/Nrf2/ARE signaling pathway. One group of animals were treated with Titania (0.045 and 0.075 g/rat) alone while the other with added melatonin (1 mg/kg and 3 mg/kg) and behavioral alterations were assessed using OFT (open field test). Neurochemical and histopathological changes were also studied in the hippocampus by analyzing kelch ECH associating protein 1 (Keap1), nuclear factor erythroid 2-related factor 2 (Nrf2), and antioxidant response element (ARE). It was seen that the animals with added Melatonin had improved behavioral scores in the OFT, like anxiety and motor dysfunction triggered by TiO2. Melatonin also reduced lipid peroxidation, ROS, GSSG, IL1ß, TNFα, Bax, and Keap1 levels, but boosted GSH, GPx, GR, SOD,IL10,IL4, Bcl2, Nrf2, and ARE levels and improved quadruple mitochondrial enzyme complex activity in titania-treated animals. Histopathological examination showed melatonin induced cytoprotection against vacuolization and necrosis in granular cells of DG and pyramidal cells of CA1 area of the hippocampus. In our study, pretreatment with melatonin reduced titania-induced neurotoxicity in the hippocampus through a mechanism potentially mediated by the Keap-1/Nrf2/ARE pathway.

Lactation ameliorates neurobehavioral outcomes in the ischemic rat dams.

AIMS: Cardiac arrest and stroke as a life-threatening event that may occur in throughout the female life, especially during pregnancy or after delivery. Previous studies demonstrated that cerebral ischemia during pregnancy or the puerperium is a rare occurrence but is associated with significant mortality and high morbidity. This study was designed to assess the effects of pregnancy and lactation on behavioral deficits, neural density, and angiogenesis in rat dams undergoing global ischemia. MATERIALS AND METHODS: Thirty-two female Wistar rats were divided into four groups: virgin-Sham (Vir-Sham) group, virgin-ischemic (Vir-Isc) group, pregnancy-lactation-sham (P-L-Sham) group, and pregnancy-lactation-ischemic (P-L-Isc) group. Global brain ischemia was induced in ischemic groups by using the 2-vessel occlusion (2-VO) model at the end of lactation phase. Seven days after 2-VO, anxiety-like signals and passive avoidance memory tests were assessed in animals. KEY FINDINGS: We found that the lactation significantly improved memory and reduced anxiety-like signals in P-L-Isc group as compared with Vir-Isc group. Moreover, angiogenesis and neural density significantly increased in the P-L-Isc group as compared with the Vir-Isc group. SIGNIFICANCE: This finding for the first time indicated that lactation protects the maternal brain against ischemic insult partly through promoting angiogenesis and neurogenesis.

Pharmacological evidence for lithium-induced neuroprotection against methamphetamine-induced neurodegeneration via Akt-1/GSK3 and CREB-BDNF signaling pathways.

OBJECTIVES: Neurodegeneration is an outcome of Methamphetamine (METH) abuse. Studies have emphasized on the neuroprotective properties of lithium. The current study is designed towards evaluating the role of Akt-1/GSK3 and CREB-BDNF signaling pathways in mediating lithium neuroprotection against METH-induced neurodegeneration in rats. MATERIALS AND METHODS: Sixty adult male rats were randomly divided into five groups: control group (received 0.7 ml normal saline per rat for 28 days), METH group (given 10 mg/kg of METH intraperitoneally for 28 days), groups 3, 4, and 5 (given METH (10 mg/kg) and lithium (75, 150, and 300 mg/kg intraperitoneally, individually for 28 days). Morris water maze (MWM) was used to assess mental functions. In addition to hippocampal neurodegeneration, Brain-derived neurotrophic factor (BDNF), cAMP response element binding (CREB), Glycogen synthase kinase 3 (GSK3), and Protein kinase B (Akt-1) were assessed in isolated hippocampus. RESULTS: METH abuse caused marked disorders in learning and memory that were dramatically improved with various doses of lithium. Furthermore, METH increased lipid peroxidation and the levels of oxidized form of interleukin 1 beta (IL-1ß), glutathione (GSSG), Bax, tumor necrosis factor alpha (TNF-α), and GSK3, while attenuating the extent of glutathione (reduced form (GSH)), P-CREB, Bcl-2, BDNF, and Akt-1 in the hippocampus. Moreover, METH declined superoxide dismutase (SOD), glutathione reductase (GR), and glutathione peroxidase (GPx) activity in the hippocampus. Conversely, lithium attenuated METH-stimulated apoptosis, oxidative stress, and inflammation; while improving the extent of BDNF and P-CREB. CONCLUSION: Probably lithium possesses neuroprotection against METH-stimulated neurodegeneration in the hippocampus via Akt-1/GSK3ß and CREB/BDNF signaling pathways.

Topiramate via NMDA, AMPA/kainate, GABAA and Alpha2 receptors and by modulation of CREB/BDNF and Akt/GSK3 signaling pathway exerts neuroprotective effects against methylphenidate-induced neurotoxicity in rats.

Chronic abuse of methylphenidate (MPH) often causes neuronal cell death. Topiramate (TPM) carries neuroprotective effects, but its exact mechanism of action remains unclear. In the present study, the role of various doses of TPM and its possible mechanisms, receptors and signaling pathways involved against MPH-induced hippocampal neurodegeneration were evaluated in vivo. Thus, domoic acid (DOM) was used as AMPA/kainate receptor agonist, bicuculline (BIC) as GABAA receptor antagonist, ketamine (KET) as NMDA receptor antagonist, yohimbine (YOH) as α2 adrenergic receptor antagonist and haloperidol (HAL) was used as dopamine D2 receptor antagonist. Open field test (OFT) was used to investigate the disturbances in motor activity. Hippocampal neurodegenerative parameters were evaluated. Protein expressions of CREB/BDNF and Akt/GSK3 signaling pathways were also evaluated. Cresyl violet staining was performed to show and confirm the changes in the shape of the cells. TPM (70 and 100 mg/kg) reduced MPH-induced rise in lipid peroxidation, oxidized form of glutathione (GSSG), IL-1ß and TNF-α levels, Bax expression and motor activity disturbances. In addition, TPM treatment increased Bcl-2 expression, the level of reduced form of glutathione (GSH) and the levels and activities of superoxide dismutase, glutathione peroxidase and glutathione reductase enzymes. TPM also inhibited MPH-induced hippocampal degeneration. Pretreatment of animals with DOM, BIC, KET and YOH inhibited TPM-induced neuroprotection and increased oxidative stress, neuroinflammation, neuroapoptosis and neurodegeneration while reducing CREB, BDNF and Akt protein expressions. Also pretreatment with DOM, BIC, KET and YOH inhibited TPM-induced decreases in GSK3. It can be concluded that the mentioned receptors by modulation of CREB/BDNF and Akt/GSK3 pathways, are involved in neuroprotection of TPM against MPH-induced neurodegeneration.

The Neuroprotective Effect of Curcumin Against Nicotine-Induced Neurotoxicity is Mediated by CREB-BDNF Signaling Pathway.

Nicotine abuse adversely affects brain and causes apoptotic neurodegeneration. Curcumin- a bright yellow chemical compound found in turmeric is associated with neuroprotective properties. The current study was designed to evaluate the role of CREB-BDNF signaling in mediating the neuroprotective effects of curcumin against nicotine-induced apoptosis, oxidative stress and inflammation in rats. Sixty adult male rats were divided randomly into six groups. Group 1 received 0.7 ml/rat normal saline, group 2 received 6 mg/kg nicotine. Groups 3, 4, 5 and 6 were treated concurrently with nicotine (6 mg/kg) and curcumin (10, 20, 40 and 60 mg/kg i.p. respectively) for 21 days. Open Field Test (OFT) was used to evaluate the motor activity. Hippocampal oxidative, anti-oxidant, inflammatory and apoptotic factors were evaluated. Furthermore, phosphorylated brain cyclic adenosine monophosphate (cAMP) response element binding protein (P-CREB) and brain derived neurotrophic factor (BDNF) levels were studied at gene and protein levels. We found that nicotine disturbed the motor activity in OFT and simultaneous treatment with curcumin (40 and 60 mg/kg) reduced the nicotine-induced motor activity disturbances. In addition, nicotine treatment increased lipid peroxidation and the levels of GSH, IL-1ß, TNF-α and Bax, while reducing Bcl-2, P-CREB and BDNF levels in the hippocampus. Nicotine also reduced the activity of superoxide dismutase, glutathione peroxidase and glutathione reductase in hippocampus. In contrast, various doses of curcumin attenuated nicotine-induced apoptosis, oxidative stress and inflammation; while elevating P-CREB and BDNF levels. Thus, curcumin via activation of P-CREB/BDNF signaling pathway, confers neuroprotection against nicotine-induced inflammation, apoptosis and oxidative stress.

Effect of Lactation on myocardial vulnerability to ischemic insult in rats / Efeito da Lactação sobre a Vulnerabilidade do Miocárdio ao Insulto Isquêmico em Ratas

Abstract Background: Cardiovascular diseases are the leading cause of mortality and long-term disability worldwide. Various studies have suggested a protective effect of lactation in reducing the risk of cardiovascular diseases. Objective: This study was designed to assess the effects of pregnancy and lactation on the vulnerability of the myocardium to an ischemic insult. Methods: Eighteen female rats were randomly divided into three groups: ischemia-reperfusion (IR), in which the hearts of virgin rats underwent IR (n = 6); lactating, in which the rats nursed their pups for 3 weeks and the maternal hearts were then submitted to IR (n = 6); and non-lactating, in which the pups were separated after birth and the maternal hearts were submitted to IR (n = 6). Outcome measures included heart rate (HR), left ventricular developed pressure (LVDP), rate pressure product (RPP), ratio of the infarct size to the area at risk (IS/AAR %), and ventricular arrhythmias - premature ventricular contraction (PVC) and ventricular tachycardia (VT). Results: The IS/AAR was markedly decreased in the lactating group when compared with the non-lactating group (13.2 ± 2.5 versus 39.7 ± 3.5, p < 0.001) and the IR group (13.2 ± 2.5 versus 34.0 ± 4.7, p < 0.05). The evaluation of IR-induced ventricular arrhythmias indicated that the number of compound PVCs during ischemia, and the number and duration of VTs during ischemia and in the first 5 minutes of reperfusion in the non-lactating group were significantly (p < 0.05) higher than those in the lactating and IR groups. Conclusion: Lactation induced early-onset cardioprotective effects, while rats that were not allowed to nurse their pups were more susceptible to myocardial IR injury.

Resumo Fundamento: As doenças cardiovasculares são a principal causa de mortalidade e invalidez a longo prazo a nível mundial. Diversos estudos têm sugerido um efeito protetor da lactação na redução do risco para doenças cardiovasculares. Objetivo: Este estudo foi desenvolvido para avaliar os efeitos da gestação e da lactação sobre a vulnerabilidade do miocárdio ao insulto isquêmico. Métodos: Dezoito ratas foram divididas aleatoriamente em três grupos: isquemia-reperfusão (IR), no qual os corações de ratas virgens foram submetidos à IR (n = 6); lactantes, no qual as ratas amamentaram seus filhotes por 3 semanas e os corações maternos foram, em seguida, submetidos à IR (n = 6); e não lactantes, no qual os filhotes foram separados após o nascimento e os corações maternos foram submetidos à IR (n = 6). As medidas de desfecho incluíram frequência cardíaca (FC), pressão desenvolvida no ventrículo esquerdo (PDVE), duplo produto (DP), razão do tamanho do infarto sobre a área sob risco (TI/ASR %) e arritmias ventriculares - contração ventricular prematura (CVP) e taquicardia ventricular (TV). Resultados: O TI/ASR foi substancialmente menor no grupo de lactantes quando comparado ao grupo de não lactantes (13,2 ± 2,5 versus 39,7 ± 3,5, p < 0,001) e ao grupo IR (13,2 ± 2,5 versus 34,0 ± 4,7, p < 0,05). A avaliação das arritmias ventriculares induzidas pela IR indicou que o número de CVPs compostas na isquemia, e o número e a duração das TVs na isquemia e nos primeiros 5 minutos de reperfusão no grupo de não lactantes foram significativamente (p < 0,05) mais elevados do que os encontrados nos grupos IR e de lactantes. Conclusão: A lactação induziu o aparecimento precoce de efeitos cardioprotetores, enquanto ratas que não foram permitidas a amamentar seus filhotes se mostraram mais suscetíveis à lesão miocárdica por IR.

Effect of Lactation on myocardial vulnerability to ischemic insult in rats.

Background: Cardiovascular diseases are the leading cause of mortality and long-term disability worldwide. Various studies have suggested a protective effect of lactation in reducing the risk of cardiovascular diseases. Objective: This study was designed to assess the effects of pregnancy and lactation on the vulnerability of the myocardium to an ischemic insult. Methods: Eighteen female rats were randomly divided into three groups: ischemia-reperfusion (IR), in which the hearts of virgin rats underwent IR (n = 6); lactating, in which the rats nursed their pups for 3 weeks and the maternal hearts were then submitted to IR (n = 6); and non-lactating, in which the pups were separated after birth and the maternal hearts were submitted to IR (n = 6). Outcome measures included heart rate (HR), left ventricular developed pressure (LVDP), rate pressure product (RPP), ratio of the infarct size to the area at risk (IS/AAR %), and ventricular arrhythmias - premature ventricular contraction (PVC) and ventricular tachycardia (VT). Results: The IS/AAR was markedly decreased in the lactating group when compared with the non-lactating group (13.2 ± 2.5 versus 39.7 ± 3.5, p < 0.001) and the IR group (13.2 ± 2.5 versus 34.0 ± 4.7, p < 0.05). The evaluation of IR-induced ventricular arrhythmias indicated that the number of compound PVCs during ischemia, and the number and duration of VTs during ischemia and in the first 5 minutes of reperfusion in the non-lactating group were significantly (p < 0.05) higher than those in the lactating and IR groups. Conclusion: Lactation induced early-onset cardioprotective effects, while rats that were not allowed to nurse their pups were more susceptible to myocardial IR injury.

Fundamento: As doenças cardiovasculares são a principal causa de mortalidade e invalidez a longo prazo a nível mundial. Diversos estudos têm sugerido um efeito protetor da lactação na redução do risco para doenças cardiovasculares. Objetivo: Este estudo foi desenvolvido para avaliar os efeitos da gestação e da lactação sobre a vulnerabilidade do miocárdio ao insulto isquêmico. Métodos: Dezoito ratas foram divididas aleatoriamente em três grupos: isquemia-reperfusão (IR), no qual os corações de ratas virgens foram submetidos à IR (n = 6); lactantes, no qual as ratas amamentaram seus filhotes por 3 semanas e os corações maternos foram, em seguida, submetidos à IR (n = 6); e não lactantes, no qual os filhotes foram separados após o nascimento e os corações maternos foram submetidos à IR (n = 6). As medidas de desfecho incluíram frequência cardíaca (FC), pressão desenvolvida no ventrículo esquerdo (PDVE), duplo produto (DP), razão do tamanho do infarto sobre a área sob risco (TI/ASR %) e arritmias ventriculares - contração ventricular prematura (CVP) e taquicardia ventricular (TV). Resultados: O TI/ASR foi substancialmente menor no grupo de lactantes quando comparado ao grupo de não lactantes (13,2 ± 2,5 versus 39,7 ± 3,5, p < 0,001) e ao grupo IR (13,2 ± 2,5 versus 34,0 ± 4,7, p < 0,05). A avaliação das arritmias ventriculares induzidas pela IR indicou que o número de CVPs compostas na isquemia, e o número e a duração das TVs na isquemia e nos primeiros 5 minutos de reperfusão no grupo de não lactantes foram significativamente (p < 0,05) mais elevados do que os encontrados nos grupos IR e de lactantes. Conclusão: A lactação induziu o aparecimento precoce de efeitos cardioprotetores, enquanto ratas que não foram permitidas a amamentar seus filhotes se mostraram mais suscetíveis à lesão miocárdica por IR.

Curcumin confers neuroprotection against alcohol-induced hippocampal neurodegeneration via CREB-BDNF pathway in rats.

BACKGROUND: Alcohol abuse causes severe damage to the brain neurons. Studies have reported the neuroprotective effects of curcumin against alcohol-induced neurodegeneration. However, the precise mechanism of action remains unclear. METHODS: Seventy rats were equally divided into 7 groups (10 rats per group). Group 1 received normal saline (0.7ml/rat) and group 2 received alcohol (2g/kg/day) for 21days. Groups 3, 4, 5 and 6 concurrently received alcohol (2g/kg/day) and curcumin (10, 20, 40 and 60mg/kg, respectively) for 21days. Animals in group 7 self- administered alcohol for 21days. Group 8 treated with curcumin (60mg/kg, i.p.) alone for 21days. Open Field Test (OFT) was used to investigate motor activity in rats. Hippocampal oxidative, antioxidative and inflammatory factors were evaluated. Furthermore, brain cyclic adenosine monophosphate (cAMP) response element binding protein (CREB) and brain derived neurotrophic factor (BDNF) levels were studied at gene level by reverse transcriptase polymerase chain reaction (RT-PCR). In addition, protein expression for BDNF, CREB, phosphorylated CREB (CREB-P), Bax and Bcl-2 was determined by western blotting. RESULT: Voluntary and involuntary administration of alcohol altered motor activity in OFT, and curcumin treatment inhibited this alcohol-induced motor disturbance. Also, alcohol administration augmented lipid peroxidation, mitochondrial oxidized glutathione (GSSG), interleukin-1 beta (IL-1ß), tumor necrosis factor-alpha (TNF-α) and Bax levels in isolated hippocampal tissues. Furthermore, alcohol-induced significant reduction were observed in reduced form of glutathione (GSH), superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione reductase (GR) activities and CREB, BDNF and Bcl-2 levels. Also curcumin alone did not change the behavior and biochemical and molecular parameters. CONCLUSION: Curcumin can act as a neuroprotective agent against neurodegenerative effects of alcohol abuse, probably via activation of CREB-BDNF signaling pathway.

Effects of acute doses of methylphenidate on inflammation and oxidative stress in isolated hippocampus and cerebral cortex of adult rats.

Methylphenidate (MPH) is a stimulatory agent in brain with unknown long-term consequences. In this study, MPH-induced neurodegeneration in adult rat brain was assessed. Rats were acutely treated with different doses of MPH. Open Field Test was used to investigate anxiety and depression levels. Inflammatory factors and anti-oxidant activity were also evaluated in isolated hippocampus and cerebral cortex. MPH treated groups (10 and 20 mg/kg) demonstrated anxiety and depression like behavior in OFT. MPH significantly increased lipid peroxidation, GSSG level, IL-1ß and TNF-α in isolated tissues. In addition, MPH at the same doses (10 and 20 mg/kg) reduced GSH, superoxide dismutase, glutathione peroxidase and glutathione reductase activity significantly in hippocampus and cerebral cortex. In conclusion, acute administration of high doses of MPH can cause oxidative and inflammatory changes in brain cells and induce neurodegeneration in hippocampus and cerebral cortex of adult rats.

Study of the effects of controlled morphine administration for treatment of anxiety, depression and cognition impairment in morphine-addicted rats.

BACKGROUND: Morphine dependency usually results in undesired outcomes such as anxiety, depression, and cognitive alterations. In this study, morphine was used to manage morphine dependence-induced anxiety, depression, and learning and memory disturbances. MATERIALS AND METHODS: Forty rats were divided equally into five groups. Group 1 received saline for 21 days. Groups 2-5 were dependent by increasing administration of morphine (15-45 mg/kg) for 7 days. For the next 14 days, morphine was administered as the following regimen: Group 2: once daily; 45 mg/kg (positive controls), Group 3: the same dose with an increasing interval (6 h longer than the previous intervals each time), Group 4: the same dose with an irregular intervals (12, 24, 36 h intervals interchangeably), and Group 5: decreasing doses once daily (every time 2.5 mg/kg less than the former dosage). On days 22-26, elevated plus maze (EPM), open field test (OFT), forced swim test (FST), and tail suspension test (TST) were performed to investigate anxiety level and depression in animals. Between 17th and 21st days, Morris water maze (MWM) was used to evaluate the spatial learning and memory. RESULTS: Chronic morphine administration caused depression and anxiety as observed by FST, EPM, and TST and decreased motor activity in OFT and caused impairment in learning and memory performance in MWM. Treatment with our protocol as increasing interval, irregular interval, and decreasing dosage of morphine caused marked reduction in depression, anxiety, and improved cognition performance compared with positive control group; and attenuated motor deficits in morphine-dependent rats, remarkably. CONCLUSIONS: Change in dosage regimens of morphine can reduce morphine-induced anxiety, depression, and cognitive impairments.

Synergistic Effects of Social Isolation and Morphine Addiction on Reduced Neurogenesis and BDNF Levels and the Resultant Deficits in Cognition and Emotional State in Male Rats.

INTRODUCTION: Addiction to drugs of abuse is a devastating condition which results in deterioration of brain function. On the other hand, social isolation also produces cognitive deficits such as learning and memory impairment. This study was designed to evaluate the potential negative synergistic effects of social isolation and morphine addiction on brain functions. METHODS AND MATERIAL: One hundred and two Sprague-Dawley rats were randomly divided into four groups for assessing neurogenesis and behaviour: group-housed, isolated, morphine-treated group-housed and morphine-treated isolated groups. Morphine- treated animals received BrdU (50 mg/kg; i.p.) and Morphine (0.75 mg/rat; i.p.) for 14 consecutive days, whereas, control rats received BrdU (50 mg/kg; i.p.) only. At the end of the study, Morris water maze and elevated plus maze tasks were performed to assess spatial working memory and anxiety levels, respectively. Furthermore, neurogenesis and BDNF levels were studied. RESULTS: Reference and working memory was markedly impaired in isolated and morphine-treated isolated rats as compared to group-housed rats and morphine-treated group-housed rats, respectively. Neurogenesis and BDNF levels were reduced in isolated and morphine-treated isolated rats as compared to group-housed rats and morphine-treated group-housed rats, respectively. Furthermore, rats in both isolated groups demonstrated low anxiety levels when compared to group housed groups. CONCLUSION: Isolation during addiction imparts devastating effects on brain. Thus, socialization of addicts can minimize addiction - induce cognitive deficits and improve neurogenesis.

Protective effects of forced exercise against nicotine-induced anxiety, depression and cognition impairment in rat.

BACKGROUND: Nicotine is one of the psychostimulant agents displaying parasympathomimetic activity; the chronic neurochemical and behavioral effects of nicotine remain unclear. Exercise lowers stress and anxiety and can act as a non-pharmacologic neuroprotective agent. In this study, the protective effects of exercise in nicotine withdrawal syndrome-induced anxiety, depression, and cognition impairment were investigated. METHODS: Seventy adult male rats were divided randomly into five groups. Group 1 served as negative control and received normal saline (0.2 mL/rat, i.p.) for 30 days, whereas group 2 (as positive control) received nicotine (6 mg/kg/day, s.c.) for the first 15 days. Groups 4, 5, and 6 were treated with nicotine (6 mg/kg/day, s.c.) for the first 15 days and then were treated with forced exercise, bupropion (20 mg/kg/day, i.p.), or a combination of the two for the following 15 days. Between day 25 and day 30, Morris water maze was used to evaluate spatial learning and memory. From days 31 to 35, the elevated plus maze (EPM), open field test (OFT), forced swim test (FST), and tail suspension test (TST) were used to investigate the level of anxiety and depression in the subjects. RESULTS: Nicotine-dependent animals indicated a reflective depression and anxiety in a dose-dependent manner in FST, EPM, and TST, which were significantly different from the control group and also can significantly attenuate the motor activity and anxiety in OFT. CONCLUSIONS: Forced exercise, bupropion, or their combination can attenuate nicotine cessation-induced anxiety, depression, and motor activity in the mentioned behavioral assay. We conclude that forced exercise can protect the brain against nicotine withdrawal-induced anxiety, depression, and cognitive alteration.

The effect of various morphine weaning regimens on the sequelae of opioid tolerance involving physical dependency, anxiety and hippocampus cell neurodegeneration in rats.

Chronic consumption of morphine induces physical dependency, anxiety, and neurodegeneration. In this study, morphine on its own has been used for the management of morphine-induced dependency, oxidative stress, and apoptosis. Forty-eight male rats were randomly divided into six groups. Rats in groups 1-5 were made morphine dependent by an increasing manner of morphine for 7 days (15-45 mg/kg). For the next 14 days, morphine was administered using the following regimen: (i) once daily 45 mg/kg (positive controls), (ii) the same dose at additional intervals (6 h longer than the previous intervals each time), (iii) 45 mg/kg of morphine at irregular intervals like of 12, 24, 36 h, (iv) decreasing dose once daily (every time 2.5 mg/kg less than the former dosage). Group 5 received 45 mg/kg of morphine and 10 mg/kg of SOD mimetic agent (M40401) injection per day. Group 6 (negative control) received saline solution only. On day 22, all animals received naloxone (3 mg/kg) and their Total Withdrawal Index (TWI) and blood cortisol levels were measured. After drug treatment, hippocampus cells were isolated, and oxidative, antioxidative, and apoptotic factors were evaluated. Various regimens of morphine reduced TWI, cortisol levels, Bax activity, caspase-3, caspase-9, TNF-α, and IL-1ß and lipid peroxidation. In all treatment groups, GSH level, superoxide dismutase, glutathione peroxidase, and Bcl-2 activity were significantly increased. Furthermore, SOD mimetic agent c diminished morphine effect on SOD activity. Thus, varying the dosage regimen of morphine can reduce the severity of morphine-induced dependency and neurodegeneration.

Protective effects of various dosage of Curcumin against morphine induced apoptosis and oxidative stress in rat isolated hippocampus.

BACKGROUND: During recent years, the defensive role of Curcumin against oxidative stress and apoptosis has been experimentally documented. Long term consumption of morphine induces apoptosis and oxidative stress which may cause serious damage to brain cells. To investigate whether Curcumin could protect rat's hippocampus against morphine induced destruction, we assessed isolated hippocampus cells for oxidative stress, anti oxidant factor and apoptotic factor activities. METHODS: For this, 40 adult male rats were taken and randomly allocated to one of the five groups. Groups 1 and 2 received morphine (45 mg/kg) and normal saline (0.2 ml/rat) respectively for four weeks. Groups 3, 4 and 5 concurrently were treated with morphine (45 mg/kg, sc) and Curcumin (10, 20 and 40 mg/kg) for four weeks. RESULTS: The results showed that morphine significantly increased lipid peroxidation, mitochondrial GSH level, concentration of Bax; caspase-3 and caspase-9 activities while decreasing Bcl-2 concentration. Further, a significant decrease in superoxide dismutase and glutathione peroxidase activity was also observed. Various dosage of Curcumin attenuated these effects by significantly lowering lipid peroxidation, GSSG level, Bax concentration, caspase-3 and caspase-9 activities, while increasing superoxide dismutase and glutathione peroxidase activity, GSH level and Bcl-2 concentration. CONCLUSIONS: These findings have demonstrated that Curcumin can act as an antioxidant and antiapoptotic agent against damage induced by morphine dependence.