DOX-induced Neurotoxicity Research Articles

Neurotoxicity of the antineoplastic drugs: "Doxorubicin" as an example.

There is an increased prevalence of cancer, and chemotherapy is widely and routinely utilized to manage the majority of cancers; however, administration of chemotherapeutic drugs has faced limitations concerning the "off-target" cytotoxicity. Chemobrain and impairment of neurocognitive functions have been observed in a significant fraction of cancer patients or survivors and reduce their life quality; this could be ascribed to the ability of chemotherapeutic drugs to alter the structure and function of the brain. Doxorubicin (DOX), an FDA-approved chemotherapeutic drug with therapeutic effectiveness, is commonly used to treat several carcinomas clinically. DOX-triggered neurotoxicity is the most serious adverse reaction after DOX-induced cardiotoxicity which greatly limits its clinical application. DOX-induced neurotoxicity is a net of multiple mechanisms that have been verified in pre-clinical and clinical studies, such as oxidative stress, neuroinflammation, mitochondrial disruption, apoptosis, autophagy, disruption of neurotransmitters, and impairment of neurogenesis. There is a massive need for developing novel therapeutics for both cancer and DOX-associated neurotoxicity; therefore investigating the implicated mechanisms of DOX-induced chemobrain will reveal multi-targets for novel curative strategies. Recently, various neuroprotective mechanisms were employed to mitigate DOX-mediated neurotoxicity. For this purpose, therapeutic interventions using pharmacological compounds were developed to protect healthy "off-target" tissues from DOX-induced toxicity. In addition, nanoplatforms were used to enable target delivery of DOX; to prevent its deposition in non-cancerous tissues. The aim of the current review is to provide some reference value for the future management of DOX-induced neurotoxicity and to summarize the underlying mechanisms of DOX-mediated neurotoxicity and the potential therapeutic interventions.

Melatonin mitigates doxorubicin induced chemo brain in a rat model in a NRF2/p53–SIRT1 dependent pathway

Cancer is a critical health problem, and chemotherapy administration is mandatory for its eradication. However, chemotherapy like doxorubicin (Dox) has serious side-effects including cognitive impairment or chemo brain. Melatonin is a neuroprotective agent that has antioxidant, and anti-inflammatory effects. We aimed to explore melatonin's effect on Dox-induced chemo brain to discover new mechanisms associated with Dox-induced neurotoxicity and try to prevent its occurrence. Thirty-two male albino rats had been equally divided into four groups; control, melatonin-administrated, Dox-induced chemo brain, and melatonin + Dox treated. On the 9th day, brain had been excised after scarification and had been assessed for reactive oxygen species measurement, histopathological analysis, immunohistochemical, gene and protein expressions for the nuclear factor erythroid 2-related factor 2 (Nrf2), p53 and Silent information regulator 2 homolog 1 (SIRT1). Our results show that melatonin coadministration diminished Dox induced hippocampal and prefrontal cortex (PFC) cellular degeneration. It alleviated Nitric Oxide (NO) level and reversed the decline of antioxidant enzyme activities. It also upregulated Nrf2, SIRT1 and downregulated p53 gene expression in rats receiving Dox. Moreover, melatonin elevated the protein expression level of Nrf2, SIRT1 and reduced p53 corresponding to immunohistochemical results. The data suggested that melatonin can mitigate Dox-induced neurotoxicity by aggravating the endogenous antioxidants and inducing neurogenesis through activation of Nrf2/p53–SIRT1signaling pathway in adult rats' PFC. These effects were associated with Nrf2, SIRT1 activation and p53 inhibition. This could be guidance to add melatonin as an adjuvant supplement to Dox regimens to limit its adverse effect on the brain function.

Agomelatine ameliorates doxorubicin-induced cortical and hippocampal brain injury via inhibition of TNF-alpha/NF-kB pathway

Side effects of doxorubicin (DOX) are mainly due to oxidative stress, with the involvement of inflammatory and apoptotic mechanisms. Agomelatine (AGO) is a melatonin receptor agonist with antioxidant, anti-inflammatory, and anti-apoptotic features. This study aimed to evaluate the effects of AGO with different doses on DOX-induced neurotoxicity. Rats were divided into four groups as control, DOX (40 mg/kg, intraperitoneal single dose), DOX + AGO20 (20 mg/kg AGO oral gavage for 14 days), and DOX + AGO40 (40 mg/kg AGO oral gavage for 14 days). On day 14, brain tissues were collected for biochemical, histopathological, and genetic examinations. DOX significantly increased malondialdehyde and decreased superoxide dismutase and catalase (CAT) levels. CAT levels were significantly increased only in the DOX + AGO40 group compared to the DOX group (p = 0.040) while other changes in oxidant and antioxidant indicators were insignificant. DOX-induced significant increases in TNF-alpha and NF-κB were reversed following both low and high-dose AGO administration in a dose-dependent manner (p < 0.001 for both doses). Cellular shrinkage, pycnotic change, and vacuolization in apoptotic bodies were apparent in the cortical and hippocampal areas of DOX-treated samples. Both doses of AGO alleviated these histopathological changes (p = 0.01 for AGO20 and p = 0.05 for AGO40). Significantly increased apoptosis shown with caspase-3 immunostaining in the DOX group was alleviated following AGO administration, with additional improvement after high-dose treatment (p < 0.01 for DOX compared to both AGO groups and p < 0.05 for AGO40 compared to AGO20). AGO can be protective against DOX-induced neurotoxicity by antioxidant, anti-inflammatory, and anti-apoptotic mechanisms in a dose-dependent manner.

Agomelatine protects hippocampal neurons against doxorubicin induced toxicity

Doxorubicin (DOX) is a powerful chemotherapy drug used in numerous cancer treatments, known to causes neurotoxicity and impair cognitive function in cancer patients. The main mechanism thought to be responsible for the neuronal damage related to chemotherapy is oxidative stress. Agomelatine (AGM) has recently been identified as a neuroprotective agent against toxicity and the effect of AGM on DOX-induced neurotoxicity was investigated in this study. In order to evaluate the effect of AGM on oxidative stress and apoptosis, malondialdehyde (MDA), lactate dehydrogenase (LDH), superoxide dismutase (SOD), catalase (CAT), and Caspase-3 expression were analyzed in the HT-22 cell line. AGM considerably reduced oxidative damage due to DOX in vitro. MDA and Caspase-3 were considerably higher in the DOX group. These values were dramatically decreased by AGM. AGM greatly increased the CAT and SOD levels when compared to the DOX group. These results suggest that DOX therapy alters antioxidant status in hippocampus, a critical cognition-related region. So if we are aware of the functional effects of DOX, it is possible to avoid some of the disabling side effects of chemotherapy in cancer patients and may prevent these effects with antioxidant agents such as AGM

Curcumin protects against doxorubicin induced oxidative stress by regulating the Keap1-Nrf2-ARE and autophagy signaling pathways

BackgroundDoxorubicin (DOX)-induced neurotoxicity is widely reported in previous studies. Oxidative stress has been validated as a critical event involved in DOX-induced neurotoxicity. As a selective autophagy adaptor protein, p62 is reported to regulate Keap1-Nrf2-ARE antioxidant pathway in response to oxidative stress. Curcumin (CUR) relieves depressive-like state through the mitigation of oxidative stress and the activation of Nrf2-ARE signaling pathway. However, the exact mechanism of CUR in alleviating DOX-induced neurotoxicity is still unknown.Materials and methodsThe rats were randomly divided into three groups: control group, DOX group, and DOX + CUR group. At the end of 3 weeks, the behavior tests as sucrose preference test (SPT), forced swimming test (FST), and novelty-suppressed feeding test (NSFT) were performed to assess anxiety- and depression-like behaviors. The rats were sacrificed after behavior tests, and the brain tissues were collected for biochemical analysis.ResultsIt was observed that the administration of CUR could effectively reverse DOX-induced depressive-like behaviors. The exposure of DOX activated autophagy and increased oxidative stress levels, and the administration of CUR could significantly inhibit DOX-induced autophagy and suppress oxidative stress. More importantly, we also found that Keap1-Nrf2-ARE signaling pathway was involved in DOX-induced neurotoxicity and oxidative stress regulated by autophagy.ConclusionOur study demonstrated that CUR could effectively reverse DOX-induced neurotoxicity through suppressing autophagy and mitigating oxidative stress and endoplasmic reticulum (ER) stress.

Activation of SIRT-1 Pathway by Nanoceria Sheds Light on Its Ameliorative Effect on Doxorubicin-Induced Cognitive Impairment (Chemobrain): Restraining Its Neuroinflammation, Synaptic Dysplasticity and Apoptosis.

Chemo fog is one of the most serious health concerns encountered by cancer survivors receiving doxorubicin (DOX)-based chemotherapy. Oxidative stress, neuroinflammation, apoptosis and impairment of synaptic plasticity are regarded as the key factors implicated in DOX-induced cognitive impairment. This research aimed to assess the possible neuroprotective effect of cerium oxide nanoparticles (CeNPs) against DOX-induced neurotoxicity. Forty-eight rats were divided into four groups (12 rats/group): control group, CeNPs group (received oral CeNPs solution (35 mg/kg) daily for 4 weeks), and DOX group (were administered DOX intraperitoneally (2 mg/kg, once/week for 4 weeks)) and DOX+ CeNPs group. The findings revealed that CeNPs mitigated behavioral alterations in DOX-induced cognitive deficit. Additionally, CeNPs alleviated the histopathological abnormalities in hippocampus and ameliorated DOX-induced neuroinflammation by downregulating the expression of NF-κB, TNF-α, IL-1β and IL6. In addition, CeNPs antagonized the apoptosis through reducing the protein expression of cytochrome c and caspase 3. In addition, it stimulated the antioxidant defense, as indicated by upregulating the expression of the Nrf2, HO-1 and PGC-1α genes. CeNPs improved synaptic plasticity via acting on the BDNF. These actions were related through the modification of SIRT-1 expression. Based on the aforementioned results, CeNPs antagonized the doxorubicin-induced neurodegeneration by its antioxidant, anti-inflammatory and antiapoptotic effects, alongside its SIRT-1 mediated mechanisms.

Infliximab and/or MESNA alleviate doxorubicin-induced Alzheimer's disease-like pathology in rats: A new insight into TNF-α/Wnt/β-catenin signaling pathway

AimsThe current study aimed to elucidate the neurotoxic potential of DOX to induce AD-like pathology paying attention to the role of wingless-integrated/β-catenin (Wnt/β-catenin) signaling pathway. A major aim was to evaluate the efficacy of infliximab (IFX) either individually or in combination with 2-mercaptoethane sulfonate sodium (MESNA) on the DOX-induced neurotoxicity in rats. MethodologyAD-like pathology was induced in adult male Wistar rats by intraperitoneal (i.p.) administration of DOX at a dose of 3.5 mg/kg twice a week for 3 weeks. DOX-injected rats were then treated with either INF at a single dose of 5 mg/kg i.p. (IFX group), MESNA at a dose of 160 mg/kg/day i.p. for 4 weeks (MESNA group) or their combination at the same specified doses (INF + MESNA group). At the end of the study period, behavioral assessment was performed and the brain tissue samples were harvested at sacrifice. Key findingsDOX-treated rats significantly exhibited AD-like brain injury, increased amyloid burden, enhanced neuroinflammation and apoptosis, and multifocal histological injury in the cerebral cortex with widespread vacuolations. IFX and MESNA significantly reversed all the aforementioned detrimental effects in the DOX-treated rats. SignificanceThe study has provided sufficient evidence of the potential of IFX and/or MESNA to ameliorate the DOX-induced neurotoxicity, with the best improvement observed with their combined administration. A new insight has been introduced into the critical role of Wnt/β-catenin activation.

Phyllanthus amarus Schumach. & Thonn. and Momordica charantia L extracts improve memory function, attenuate cholinergic and purinergic dysfunction, and suppress oxidative stress in the brain of doxorubicin–treated rats

BackgroundPhyllanthus amarus (P.A) and Momordica charantia (M.C) are common herbs known for their various pharmacological importance. However, limited studies have been done regarding their neuroactive effect. This study investigates the role of Phyllanthus amarus (P.A) and Momordica charantia (M.C) extracts on cognitive behavior and some neurochemicals associated with memory function in rats administered with doxorubicin (DOX). MethodologyNormal rats were pre-treated with P.A and M.C (200 and 400 mg/kg bwt.) for 14 days, while on the last day, DOX (15 mg/kg bwt. i.p.) was administered in a single dose. The cognitive behavior was evaluated using Y-maze and Morris Water Maze Tests. Thereafter, the biochemical assays [acetylcholinesterase (AChE), butyrylcholinesterase (BChE), arginase, 5′- nucleotidase, adenosine deaminase (ADA), angiotensin-I converting enzyme (ACE), and catalase activities, thiobarbituric acid reactive species, and non-protein thiol levels] were determined in rats’ brains. The extracts were characterized using a high-performance liquid chromatography-diode array detector (HPLC-DAD). ResultP.A and M.C extract restored cognitive behavior, nootropic-related enzyme activities, and improved antioxidant biomarkers altered by DOX. Furthermore, phenolic characterization of the extracts revealed gallic, chlorogenic, caffeic, and ellagic acids, catechin, epicatechin, rutin, quercitrin, isoquercitrin, quercetin, and kaempferol. Molecular docking analysis revealed that all the phenolic compounds detected in the studied plants had binding affinities for ACE, AChE, 5′-nucleotidase, and ADA proteins as the target proteins. ConclusionExtract from P.A and M.C effectively suppressed DOX-induced neurotoxicity by improving brain antioxidant status. Thus, they could play a significant role in restoring cognitive function altered by DOX treatment.

Terminalia muelleri extract supplementation alleviates doxorubicin-induced neurotoxicity in rats

Background Doxorubicin (DOX) is widely used to treat many human cancers, but significant brain damage limits its clinical application. Objectives To investigate the neuroprotective activity of Terminalia muelleri extract (TME) against DOX-induced neurotoxicity in rats. Materials and methods The first group served as a normal control; the second group served as a positive control which was treated with DOX (2.5 mg/kg; dissolved in saline; intraperitoneal three times/week for 2 weeks,); the third group was treated with TME at a dose of 100 mg/kg; the fourth group was pretreated with TME for 2 weeks and then coadministrated with DOX for other 2 weeks; the fifth and sixth groups were treated with DOX for 2 weeks and then posttreated with two doses of TME (100, 200 mg/kg), respectively, for another 2 weeks. The experiment lasted for 4 weeks; brain tissue samples were harvested for the measurement of toxicity such as oxidative stress, inflammation, apoptosis, neurodegeneration, and histopathological examinations. Results and conclusion DOX-treated animals showed a reduction in glutathione and superoxide dismutase along with a raise in malondialdehyde, nitric oxide, and myeloperoxidase. Also, it caused an increase in caspase-3, indicating an increased propensity for cell death, acetylcholinesterase, extracellular signal-regulated kinase, mammalian target of rapamycin with concomitant decrease in brain-derived neurotrophic factor. However, administration of TME significantly improved oxidative stress alterations, brain-derived neurotrophic factor, and apoptosis. Histological assessments of brain tissues supported the obtained biochemical finding. In conclusion, our findings disclose a potent protective role of TME by activating antioxidant, anti-inflammatory, anti-apoptotic, and neurogenesis effects, which may contribute to the safe use of DOX in cancer treatment.

Biochemical and histological alterations of doxorubicin‐induced neurotoxicity in rats: Protective role of luteolin

Doxorubicin (DOX) is a chemotherapeutic drug used in the treatment of various cancer types. DOX toxic side effects include neuronopathy and memory deficits. We investigated the effect of the antioxidant luteolin (LUT: 50 or 100 mg/kg; per os) on DOX (2 mg/kg; intraperitoneal)-induced oxidative stress (OS), inflammation, and apoptosis in the brain of Wistar rats for 14 days. We observed that LUT reduced DOX-mediated increase in OS biomarkers-catalase, superoxide dismutase, glutathione-S-transferase, and glutathione peroxidase. LUT increased glutathione and total sulphydryl levelsand alleviated DOX-induced increases in the levels of reactive oxygen and nitrogen species, lipid peroxidation, myeloperoxidase, nitric oxide, tumor necrosis factor-α, and interleukin-1β (IL-1β). Additionally, LUT suppressed caspase-3 activity, increased anti-inflammatory cytokine-IL-10 level, and reduced pathological lesions in the examined organs of rats cotreated with LUT and DOX. Collectively, cotreatment with LUT lessened DOX-induced neurotoxicity. Supplementation of LUT as a chemopreventive agent might be useful in patients undergoing DOX chemotherapy.

Neuroprotective Potential of Berberine Against Doxorubicin-Induced Toxicity in Rat's Brain.

Chemotherapy-associated neurotoxicity is one of the principal side-effects for doxorubicin (DOX)-treated cancer patients. Despite its poor-penetration across the blood-brain barrier (BBB), DOX is linked to the induction of oxidative stress and neuroinflammation. Berberine (BEB) is a natural polyphenolic alkaloid, which exhibits unique antioxidant activity and anti-inflammatory potential. The present study was performed to investigate the neuroprotective potential of BEB in a rodent model of DOX-induced neurotoxicity. Neurotoxicity was induced in rats via a single acute dose of DOX (20mg/kg/week, i.p.). BEB was administered at 50mg/kg/day orally for 10days before and 4days after DOX administration. Brain acetylcholinesterase (AChE) activities were evaluated. Oxidative stress was investigated via the colorimetric determination of lipid peroxides, glutathione reduced (GSH) contents and catalase (CAT) activities in the brain tissue. In addition, DOX-induced genotoxicity was evaluated using comet assay. DOX produced a significant elevation in AChE activities. Additionally, DOX provoked oxidative stress as evidenced from the significant elevation in lipid peroxidation along with depletion in GSH contents and CAT activities. Moreover, DOX resulted in neuroinflammation as indicated by the elevation of pro-inflammatory mediator glial fibrillary acid protein (GFAP), as well as, the pro-apoptotic nuclear factor kappa B (NF-κB) and caspase-3 in brain tissue. Co-treatment with BEB significantly counteracted DOX-induced oxidative stress, neuroinflammation and genotoxicity. Histopathological and immunohistochemical examination supported the biochemical results. BEB demonstrated neuroprotective potential through exerting cholinergic, anti-oxidative, genoprotective, anti-inflammatory, and anti-apoptotic activities. Our findings present BEB as a promising "pre-clinical" neuroprotective agent against DOX-induced neurotoxicity during anti-neoplastic therapy.

Thymoquinone has a neuroprotective effect against inflammation, oxidative stress, and endoplasmic reticulum stress in the brain cortex, medulla, and hippocampus due to doxorubicin.

Although doxorubicin (DOX) is used in many cancer treatments, it causes neurotoxicity. In this study, the effect of thymoquinone (THQ), a powerful antioxidant, on DOX-induced neurotoxicity was evaluated. In total, 40 rats were used and 5 groups were formed. Group I: control group (n = 8); Group II: olive oil group (n = 8); Group III: the THQ group (n = 8); THQ 10 mg/kg per day was given intraperitoneally (i.p.) throughout the experiment; group IV: DOX group (n = 8); On Day 7 of the experiment, a single dose of 15 mg/kg intraperitoneally DOX injected; group V: DOX + THQ group (n = 8); Throughout the experiment, 10 mg/kg THQ per day and intraperitoneally 15 mg/kg DOX on Day 7 were injected. Immunohistochemically, tumor necrosis factor-α (TNF-α), interleukin-17 (IL-17), hypoxia-inducible factor 1α (HIF1-α), glucose regulatory protein 78 (GRP78), and the gene inducible by growth arrest and DNA damage 153 (GADD153) proteins were evaluated in the brain cortex, medulla, and hippocampus regions. Total oxidant status (TOS) levels and total antioxidant status (TAS) in the brain tissue were measured. TNF-α, IL-17, HIF1-α, GRP78, and GADD153 immunoreactivities significantly increased in the DOX group in the study. THQ significantly reduced these values. THQ increased the TAS level significantly and decreased the TOS level significantly compared to the DOX group. THQ may play a role as a neuroprotective agent in DOX-induced neurotoxicity in the cortex, medulla, and hippocampus regions of the brain.

Adrenomedullin protects rat dorsal root ganglion neurons against doxorubicin-induced toxicity by ameliorating oxidative stress.

Objective(s):Despite effective anticancer effects, the use of doxorubicin (DOX) is hindered due to its cardio and neurotoxicity. The neuroprotective effect of adrenomedullin (AM) was shown in several studies. The present study aimed to evaluate the possible protective effects of AM against DOX-induced toxicity in dorsal root ganglia (DRGs) neurons. Materials and Methods:Rat embryonic DRG neurons were isolated and cultured. The effect of various concentrations of DOX (0.0 to 100 µM) in the absence or presence of AM (3.125 -100 nM) on cell death, apoptosis, oxidative stress, expression of tumor necrosis-α (TNF-α), interleukin1- β (IL-1β), inducible nitric oxide synthase (iNOS), matrix metalloproteinase (MMP) 3 and 13, and SRY-related protein 9 (SOX9) were examined. Results:Based on MTT assay data, DOX decreased the viability of DRG neurons in a dose and time-dependent manner (IC50=6.88 µm) while dose-dependently, AM protected DRG neurons against DOX-induced cell death. Furthermore, results of annexin V apoptosis assay revealed the protective effects of AM (25 nm) against DOX (6.88 µM)-induced apoptosis and necrosis of DRG neurons. Also, AM significantly ameliorated DOX-induced oxidative stress in DRG neurons. Real-time PCR results showed a significant increase in the expression of TNF-α, IL-1β, iNOS, MMP 3, and MMP 13, and a decrease in the expression of SOX9 following treatment with DOX. Treatment with AM (25 nM) significantly reversed the effects of DOX on the above-mentioned genes expression.Conclusion:Our findings suggest that AM can be considered a novel ameliorating drug against DOX-induced neurotoxicity.

Protective effects of diallyl trisulfide (DATS) against doxorubicin-induced inflammation and oxidative stress in the brain of rats

Doxorubicin (DOX) is a widely used antitumor drug that causes severe neurotoxicity in patients. Diallyl trisulfide (DATS) is an organosulfur compound with established potent antioxidant and anti-inflammatory properties. Herein, we investigated the neuroprotective efficacy of DATS in preventing DOX-induced neurotoxicity in a rat model. Specifically, DATS (40 mg/kg) was administered to rats 24 h after DOX treatment, once a week for 8 weeks. Our results showed that DATS treatment led to a decrease in plasma levels of tumor necrosis factor-alpha (TNF-α) induced by DOX. DATS restored cerebral cortex and hippocampus histopathological architecture and neuronal loss. Immunohistochemical staining indicated that DATS decreased the expression of glial fibrillar acidic protein (GFAP) in DOX treated rats. Components of stress-related inflammatory proteins (TNF-α, phospho nuclear factor kappa B (NF-κB), inducible nitricoxide synthase (iNOS) and cyclooxygenase-2 (COX-2)) were all significantly increased in the DOX group, in comparison with the control group, whereas they were decreased after DATS treatment. In addition, the mRNA of antioxidant enzymes (superoxide dismutase 2 (SOD2), catalase, glutathione peroxidase 1, 4 (GPx1 and GPx4)) and antioxidant proteins (heme oxygenase-1 (HO-1), superoxide dismutase 1, 2 (SOD1 and SOD2), Γ-glutamylcysteine synthase (Γ-GCSc)) were markedly increased in DOX group compared with the control group, which were significantly attenuated by DATS treatment. The upregulation of antioxidants enzymes in DOX group was probably a compensatory effect against elevated oxidative stress induced by DOX. DATS treatment could ameliorate this oxidative stress in brain. Our results suggested that DATS has potential clinical applications in the prevention of DOX-induced neurotoxicity by ameliorating inflammatory insults and oxidative stress.

Neuroprotective potential of methanolic extract of Saraca asoca bark against doxorubicin-induced neurotoxicity

Background: Doxorubicin (DOX) is a widely used anthracycline-based anticancer agent, which causes a gradual decline in cognition on long-term usage in breast cancer patients that affect their quality of life negatively. Aim: The present study was designed to assess the neuroprotective potential of Saraca asoca bark against Dox-induced neurotoxicity, considering its previously reported anticlastogenic effect. Materials and Methods: Methanolic extract of bark was prepared by Soxhlet extraction and characterized by high-performance thin-layer chromatography (catechin-8.82%). In vitro studies were performed in IMR-32 neuroblastoma cells using cell viability and neurite growth assay to determine the neuroprotective potential of the extract against DOX-induced neurotoxicity. In vivo neuroprotection study of extract (100 and 200 mg/kg p. o) was performed by assessing episodic memory through novel object recognition test (NORT) in DOX-induced (10 cycles, 2.5 mg/kg, 5 days apart) memory deficit model. In addition, antioxidant markers and acetylcholinesterase activity in hippocampus and frontal cortex were evaluated. Results and Conclusion: The extract showed significant in vitro neuroprotection toward differentiated cells in morphological features and cell viability assessment against DOX (IC50-63.35 and 45.17 μg/ml against 1 μg/ml and 2 μg/ml DOX, respectively, and 0.46 μg/ml for DOX alone in 3-[4,5 dimethyl thiazol-2-yl]-2,5-diphenyl tetrazolium bromide assay). DOX-treated animals showed depletion in episodic memory while extract at 100 mg/kg significantly prevented it. Similar changes were observed in antioxidant markers levels in the brain. DOX treatment elevated acetylcholinesterase activity which was significantly reversed by the treatment with extract. Thus, it can be stated that the neuroprotective and antioxidant potentials of extract possibly underlie the efficacy against the DOX-induced neurotoxicity. Abbreviations Used: DOX: Doxorubicin; S. asoca: Saraca asoca; DMEM: Dulbecco's Modified Eagle's Medium (DMEM); MTT: 3-[4,5 dimethyl thiazol-2-yl]-2,5-diphenyl tetrazolium bromide; FBS: Fetal bovine serum; RA: Retinoic acid; CMC: Carboxymethyl cellulose; SOD: Superoxide dismutase; GSH: Reduced glutathione; HPTLC: High-performance thin-layer chromatography; NORT: Novel object recognition task; ITI: Intertrial interval; MPO: Myeloperoxidase; MDA: Malondialdehyde; RI: Recognition index; DI: Discrimination index.

Prophylactic and Ameliorative Effect of N-Acetylcysteine on Doxorubicin-Induced Neurotoxicity in Wister Rats

Doxorubicin (DOX) is an anthracycline antibiotic and a quinone-containing chemotherapeutic drug used for various types of cancers. However, as with most anticancer drugs, it causes many toxic effects, one of them is cognitive impairment. The present study investigated the prophylactic and ameliorative effect of n-acetylcysteine (NAC) against DOX-induced neurotoxicity in rats. Rats were divided into four groups. Control group: rats received saline. NAC treated group: rats received NAC (100 mg/kg, p.o.) daily for 35 days. DOX-treated group: rats received DOX (4 mg/kg, i.p.) for four weeks on day 7, 14, 21 and 28. DOX+NAC treated group 1: rats received NAC (100 mg/kg, p.o.) daily for 35 days and DOX (4 mg/kg, i.p.) for four weeks on day 7, 14, 21 and 28). DOX+NAC treated group 2: rats received NAC (100 mg/kg, p.o.) daily started at the 7th day of the experiment till the end of the experiment and DOX (4 mg/kg, i.p.) for four weeks on day 7, 14, 21 and 28. The present results showed a significant reduction in the body weight, which was associated with a significant increase in brain to body weight ratio in DOX-treated rats. Tumor necrosis factor (TNF-α) level, malondialdehyde (MDA) and total protein levels were significantly elevated. Whilst, reduced glutathione (GSH) and glutathione peroxidase (GPx) levels were significantly decreased. Moreover, there were histopathological abnormalities in the brain tissue of DOX-treated rats, as most of the neurons degenerated and the blood vessels surrounded with wide perivascular spaces. In addition, the neuropil was vacuolated. The present study demonstrated that NAC has a neuroprotective effect on the brain damage induced by DOX, through inhibition of inflammation and oxidative stress. This neuroprotective effect was more pronounced in DOX+NAC treated group 1, as it produced a significant increase in brain GSH and GPx levels and more improvement in the histopathological abnormality compared to DOX+NAC treated group 2.

The involvement of autophagic flux in the development and recovery of doxorubicin-induced neurotoxicity

Doxorubicin (Dox) is an effective anti-cancer agent, whose clinical use is limited by the cytotoxicity in non-target tissues, especially the heart and brain. The drug-induced neuronal damage is primarily mediated by oxidative stress, in which autophagy plays a central role. Although numerous studies indicate the involvement of autophagy in neurodegenerative diseases and brain injury, the evidence concerning autophagic process in Dox-induced neuronal death is limited. We found that repeated Dox administration induced the protein expression of LC3II and P62 and impaired autophagic flux with enhanced autophagasome accumulation in rat hippocampus, whereas two weeks after the cessation of Dox treatment, the autophagic process was restored, even stimulated, with normalized protein levels of LC3II and P62 and enhanced expression of Becline-1, indicating a compensatory response in the recovery state. Likewise, while repeated Dox exposure inhibited the hippocampal expression of lysosomal-associated membrane protein 2 (LAMP2) and cathepsin D (CTSD), and suppressed CTSD activity, the Dox-induced impaired autophagy-lysosome pathway was also restored in rats following two weeks of recovery. To further verify the role of autophagy, the autophagy inhibitor, 3-methyladenine (3-MA), was administrated daily for the two weeks of recovery period. Our data demonstrated that while the animals in the recovery state showed a significant trend to decreased oxidative damage, normalized antioxidative system and ameliorated endoplasmic reticulum (ER) stress compared with Dox-induced toxic model, 3-MA treatment abrogated the recovering process, resulting in sustained oxidative and ER stress and neuronal apoptosis. Collectively, the present study firstly provided the evidence for the involvement of autophagy in both development and recovery of Dox-induced neurotoxicity, highlighting a novel target for mitigating the chemotherapy-induced neuronal damage.

Dysregulation of Neuregulin-1/ErbB signaling in the hippocampus of rats after administration of doxorubicin.

ObjectiveLong-term use of doxorubicin (Dox) can cause neurobiological side effects associated with depression, but the underlying mechanisms remain equivocal. While recent evidence has indicated that Neuregulin-1 (NRG1) and its ErbB receptors play an essential role in neural function, much is still unknown concerning the biological link between the NRG1/ErbB pathway and the Dox-induced neurotoxicity. Therefore, we examined the protein expression of NRG1 and ErbB receptors in the hippocampus of rats following Dox treatment.Materials and methodsThe drug was administered every 2 days at a dose of 2.5 mg/kg, and the animals in different groups were treated with intraperitoneal injection for three or seven times, respectively.ResultsOur data showed that the rats treated with Dox for seven times (DoxL group) exhibited depression-like behaviors, whereas the short-term treatment (DoxS group) had no effect on the behavioral changes. Dox treatment also induced the neural apoptosis with more severe neurotoxicity. Intriguingly, the expression of NRG1 and the ratio of pErbB4/ErbB4 and pErbB2/ErbB2 were significantly decreased in the DoxL group, but enhanced activation of ErbB receptors was observed in the DoxS group. In parallel, administration of Dox for seven times suppressed the downstream Akt and ERK phosphorylation, while the Akt phosphorylation was enhanced with the administration of Dox for three times.ConclusionOur data first showed the Dox-induced alterations of the NRG1/ErbB system in the hippocampus, indicating the potential involvement of the NRG1/ErbB pathway in the Dox-induced nervous system dysfunction.

Neuroprotective Effects of dl-3-n-Butylphthalide against Doxorubicin-Induced Neuroinflammation, Oxidative Stress, Endoplasmic Reticulum Stress, and Behavioral Changes.

Doxorubicin (DOX) is a broad-spectrum antitumor drug while its use is limited due to its neurobiological side effects associated with depression. We investigated the neuroprotective efficacy of dl-3-n-butylphthalide (dl-NBP) against DOX-induced anxiety- and depression-like behaviors in rats. dl-NBP was given (30 mg/kg) daily by gavage over three weeks starting seven days before DOX administration. Elevated plus maze (EPM) test, forced swimming test (FST), and sucrose preference test (SPT) were performed to assess anxiety- and depression-like behaviors. Our study showed that the supplementation of dl-NBP significantly mitigated the behavioral changes induced by DOX. To further explore the mechanism of neuroprotection induced by dl-NBP, several biomarkers including oxidative stress markers, endoplasmic reticulum (ER) stress markers, and neuroinflammatory cytokines in the hippocampus were quantified. The results showed that dl-NBP treatment alleviated DOX-induced neural apoptosis. Meanwhile, DOX-induced oxidative stress and ER stress in the hippocampus were significantly ameliorated in dl-NBP pretreatment group. Our study found that dl-NBP alleviated the upregulation of malondialdehyde (MDA), nitric oxide (NO), CHOP, glucose-regulated protein 78 kD (GRP-78), and caspase-12 and increased the levels of reduced glutathione (GSH) and activities of catalase (CAT), glutathione reductase (GR), and glutathione peroxidase (GPx) in the hippocampus of rats exposed to DOX. Additionally, the gene expression of interleukin-6 (IL-6), interleukin-1β (IL-1β), and tumor necrosis factor-alpha (TNF-α) and protein levels of inducible nitric oxide synthase (iNOS) were significantly increased in DOX-treated group, whereas DOX-induced neuroinflammation was significantly attenuated in dl-NBP supplementation group. In conclusion, dl-NBP could alleviate DOX-induced anxiety- and depression-like behaviors via attenuating oxidative stress, ER stress, inflammatory reaction, and neural apoptosis, providing a basis as a therapeutic potential against DOX-induced neurotoxicity.

Prophylactic effects of ellagic acid and rosmarinic acid on doxorubicin-induced neurotoxicity in rats.

Doxorubicin (DOX) is a chemotherapeutic agent widely used in human malignancies. Its long-term use cause neurobiological side effects. The aim of the present study was to investigate the prophylactic effect exerted by daily administration of ellagic acid (EA) and rosmarinic acid (RA) on DOX-induced neurotoxicity in rats. Our data showed that DOX-induced significant elevation of brain malondialdehyde, tumor necrosis factor-alpha (TNF-α), inducible nitric oxide synthase (iNOS), caspase-3, and cholinesterase associated with significant reduction in reduced glutathione, monoamines namely serotonin, dopamine, as well as norepinephrine. Concomitant administration of EA (10mg/kg/day, p.o. for 14 days) and/or RA (75mg/kg/day, p.o. for 14 days) with DOX significantly mitigated the neural changes induced by DOX. Meanwhile, treatment ameliorated pro-inflammatory cytokines as TNF-α, iNOS, and attenuated oxidative stress biomarkers as well as brain monoamines. In conclusion, EA and RA can effectively protect against DOX-induced neurotoxicity, and the mechanisms underlying the neuroprotective effect are potentially associated with its antioxidant, anti-inflammatory, and antiapoptotic properties.