Minocycline inhibits mTOR signaling activation and alleviates behavioral deficits in the Wistar rats with acute ischemia stroke

2020 ◽  
Vol 19 ◽  
Author(s):  
Shengyuan Wang ◽  
Chuanling Wang ◽  
Lihua Wang ◽  
Zhiyou Cai
Keyword(s):  
Cerebral Ischemia ◽  
Ischemia Reperfusion ◽  
Mammalian Target Of Rapamycin ◽  
Mtor Signaling ◽  
Acute Ischemia ◽  
Intragastric Administration ◽  
Underlying Mechanisms ◽  
Signaling Activation ◽  
The Brain ◽  
Minocycline Therapy

Background: Mammalian target of rapamycin (mTOR) has been evidenced as a multimodal therapy in the path-ophysiological process of acute ischemic stroke (AIS). However, the pathway that minocycline targets mTOR signaling is not fully defined in the AIS pathogenesis. This study is to aim at the effects of minocycline on the mTOR signaling in the AIS process and further discover the underlying mechanisms of minocycline involved in the following change of mTOR signaling-autophagy. Methods: Cerebral ischemia/reperfusion (CIR) rat animal models were established with the transient suture occlusion into middle cerebral artery. Minocycline (50mg/kg) was given by intragastric administration. The Morris water maze was used to test the cognitive function of animals. Immunohistochemistry and immunofluorescence were introduced for testing the lev-els of synaptophysin and PSD-95. Western blot was conducted for investigating the levels of mTOR, p-mTOR (Ser2448), p70S6, p-p70S6 (Thr389), eEF2k, p-eEF2k (Ser366), p-eIF4B (Ser406), LC3, p62, synaptophysin and PSD-95. Results: Minocycline prevents cognitive decline of the MCAO stroke rats. Minocycline limits the expression of p-mTOR (Ser2448) and the downstream targets of mTOR [p70S6, p-p70S6 (Thr389), eEF2k, p-eEF2k (Ser366) and p-eIF4B (Ser406)] (P<0.01), while minocycline has no influence on mTOR. LC3-II abundance and the LC3-II/I ratio were upregu-lated in the hippocampus of the MCAO stroke rats by the minocycline therapy (P<0.01). p62 was downregulated in the hippocampus from the MCAO stroke rats administrated with minocycline therapy(P<0.01). The levels of SYP and PSD-95 were up-regulated in the brain of the MCAO stroke rats administrated with minocycline therapy. Conclusion: Minocycline prevents cognitive deficits via inhibiting mTOR signaling and enhancing autophagy process, and promoting the expression of pre-and postsynaptic proteins (synaptophysin and PSD-95) in the brain of the MCAO stroke rats. The potential neuroprotective role of minocycline in the process of cerebral ischemia may be related to mitigating is-chemia-induced synapse injury via inhibiting activation of mTOR signaling.

Exploring the Role of Remote Ischemic Preconditioning In Long Term Cognitive Impairment after Global Ischemia-Reperfusion-Induced Vascular Dementia in Mice

2020 ◽  
Author(s):  
Amteshwar Singh Jaggi
Keyword(s):  
Cognitive Impairment ◽  
Cerebral Ischemia ◽  
Vascular Dementia ◽  
Ischemic Preconditioning ◽  
Ischemia Reperfusion ◽  
Remote Ischemic Preconditioning ◽  
Global Cerebral Ischemia ◽  
Cerebral Ischemic ◽  
The Brain

Aim: The aim of the present study is to explore the neuroprotective effects of remote ischemic preconditioning in long term cognitive impairment after global cerebral ischemia induced-vascular dementia in mice. Material and methods: The mice were subjected to global cerebral ischemia by occluding the bilateral common carotid arteries for 12 minutes followed by the 24 hours of the reperfusion. The remote ischemic preconditioning stimulus was delivered in the form of 4 cycles of ischemia/reperfusion for 5 minutes each. The cerebral ischemic injury induced-long term cognitive impairment-related learning and memory alterations was assessed using morris water maze, the motor performances of the animals were evaluated using rota-rod test and neurological severity score. The cerebral infract size of the brain were quantified using triphenyltetrazolium chloride staining. Results: Global cerebral ischemia causes long term memory impairment, decreases motor performances and increases the brain infract size in animals. The delivery of remote ischemic preconditioning stimulus significantly abolished the long-term cognitive impairment and ameliorates the motor performances as well as cerebral infract size in brain. Conclusion: The remote ischemic preconditioning mediates neuro protection against global cerebral ischemic injury induced long-term cognitive impairment.

scholarly journals Preparation, Characterization, Pharmacokinetics and Biodistribution of Baicalin-Loaded Liposome on Cerebral Ischemia-Reperfusion after i.v. Administration in Rats

Molecules ◽  
2018 ◽  
Vol 23 (7) ◽  
pp. 1747 ◽  
Author(s):  
Nan Li ◽  
Lingling Feng ◽  
Yujun Tan ◽  
Yan Xiang ◽  
Ruoqi Zhang ◽  
...  
Keyword(s):  
Cerebral Ischemia ◽  
Zeta Potential ◽  
Middle Cerebral Artery ◽  
Middle Cerebral Artery Occlusion ◽  
Cerebral Artery ◽  
Ischemia Reperfusion ◽  
Artery Occlusion ◽  
Cerebral Artery Occlusion ◽  
The Brain

The dry root of Scutellaria baicalensis, has traditionally been applied in the treatment of cerebral ischemia in Chinese clinics. Baicalin (BA) is considered the key ingredient in it for the brain protection effects. The bioavailability of BA is very low because of its poor lipid and water solubility, which limits the therapeutic effects and clinical application. The aim of the present study was to develop a novel BA-loaded liposome (BA-LP) formulation to improve the drug lipophilicity and further to enhance the drug-concentration in the brain tissues. This study is also designed to investigate the pharmacokinetics of BA in the pathological conditions of stroke and evaluate the pharmacokinetic differences of BA caused by stroke after intravenous administration with BA and BA-LP. In this study, the novel BA-LP prepared in early stage were characterized by morphology, size, zeta potential, encapsulation rate and the in vitro release. The pharmacokinetics and biodistribution of BA and BA-LP were investigated by intravenous administration in rats with middle cerebral artery occlusion (MCAO) model and normal group respectively. BA-LP had a mean particle size of 160–190 nm, zeta potential of −5.7 mV, and encapsulation efficiency of 42 ± 1%. The BA-LP showed a sustained-release behavior, the in vitro drug-release kinetic model of BA-LP fit well with the biphasic dynamic model equation: Q = 1 − (60.12e0.56t − 59.08e0.0014t). Pharmacokinetic behavior in MCAO rats is not consistent with that of normal rats. The middle cerebral artery occlusion rats got higher Cmax and AUC0–t, which were about 1.5–2 times to normal rats both in BA and liposome groups. In addition, it got especially higher distribution in brain, while BA were not detected in brain tissues on normal rats. The Cmax and AUC0–t values were significantly greater with liposome than BA on both normal and MCAO rats. The tissue distribution behavior was significantly altered in the case of liposome administrated in comparison with BA, which the concentrations in the heart, liver, spleen, lungs and brain were all increased after administrated liposome, but decreased in kidneys. The TI values showed that the target of liposome was improved especially to heart, spleen and brain, and the brain’s target was higher in striatum and cerebellum. In conclusion, BA-LP might be a potential drug delivery system to improve the therapeutic efficacy of BA. In addition, these results also suggest that the pathological damages of ischemia-reperfusion have a significant impact on the pharmacokinetic traits of BA.

scholarly journals The Many Faces of Post-Ischemic Tau Protein in Brain Neurodegeneration of the Alzheimer’s Disease Type

Cells ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2213
Author(s):  
Ryszard Pluta ◽  
Stanisław J. Czuczwar ◽  
Sławomir Januszewski ◽  
Mirosław Jabłoński
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Brain Injury ◽  
Cerebral Ischemia ◽  
Tau Protein ◽  
Ischemia Reperfusion ◽  
Disease Type ◽  
Dependent Manner ◽  
Ischemic Brain ◽  
The Brain

Recent data suggest that post-ischemic brain neurodegeneration in humans and animals is associated with the modified tau protein in a manner typical of Alzheimer’s disease neuropathology. Pathological changes in the tau protein, at the gene and protein level due to cerebral ischemia, can lead to the development of Alzheimer’s disease-type neuropathology and dementia. Some studies have shown increased tau protein staining and gene expression in neurons following ischemia-reperfusion brain injury. Recent studies have found the tau protein to be associated with oxidative stress, apoptosis, autophagy, excitotoxicity, neuroinflammation, blood-brain barrier permeability, mitochondrial dysfunction, and impaired neuronal function. In this review, we discuss the interrelationship of these phenomena with post-ischemic changes in the tau protein in the brain. The tau protein may be at the intersection of many pathological mechanisms due to severe neuropathological changes in the brain following ischemia. The data indicate that an episode of cerebral ischemia activates the damage and death of neurons in the hippocampus in a tau protein-dependent manner, thus determining a novel and important mechanism for the survival and/or death of neuronal cells following ischemia. In this review, we update our understanding of proteomic and genomic changes in the tau protein in post-ischemic brain injury and present the relationship between the modified tau protein and post-ischemic neuropathology and present a positive correlation between the modified tau protein and a post-ischemic neuropathology that has characteristics of Alzheimer’s disease-type neurodegeneration.

Abstract 032: Impaired Cardiac Autophagy In Metabolic Syndrome Despite Intact AMPK And mTOR Signaling

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Nandini Ravindran ◽  
Carlos Bazan ◽  
Bruce R Ito ◽  
Roberta A Gottlieb ◽  
Robert M Mentzer
Keyword(s):  
Metabolic Syndrome ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Mammalian Target Of Rapamycin ◽  
Adenosine Monophosphate ◽  
Sprague Dawley ◽  
Downstream Target ◽  
Extracellular Milieu ◽  
Adult Rat ◽  
Underlying Mechanisms

Objective: We previously reported that basal cardiac autophagy is lower in the setting of metabolic syndrome (MetS) (obesity, dyslipidemia, insulin resistance) and is associated with attenuation of cardioprotection after ischemic preconditioning. To understand the underlying mechanisms and exclude effects of the extracellular milieu, we investigated the roles of two major cellular energy sensing pathways, adenosine monophosphate-activated protein kinase (AMPK), and mammalian target of rapamycin (mTOR), using adult rat ventricular cardiomyocytes (ARVM) isolated from Sprague Dawley (SD) and Zucker obese (ZO) rats. Methods: ARVM were cultured overnight and subjected to nutrient deprivation (1 hr), or treated with 1µM phenformin (Ph), an AMPK activator, or 5µM rapamycin (Rap), an mTOR inhibitor. Immunoblotting was used to measure phosphorylation of AMPK, p70S6 kinase (a downstream target of mTOR), LC3-I, -II, and p62 (autophagic clearance). Results: In ARVM from SD rats, starvation or Ph increased p-AMPK and decreased p-p70S6K, accompanied by increased LC3-II and 50% reduction in p62. Rapamycin decreased phosphorylation of p70S6K, increased LC3-II and decreased p62. In ZO ARVM, Ph and Rap also activated AMPK and inhibited mTOR; however, LC3-II was unchanged (Fig.) and p62 clearance was blunted. Conclusions: Despite appropriate activation of AMPK and inhibition of mTOR, autophagy is impaired in ARVM from ZO rats. These cells retain the MetS phenotype, facilitating efforts to delineate the molecular basis of impaired autophagy and vulnerability to ischemia/reperfusion injury in MetS. This could lead to new approaches to myocardial protection in at-risk patients.

Biochemical Characterization of the Brain Hippocampal Areas after Cerebral Ischemia-Reperfusion Using Raman Spectroscopy

2018 ◽  
Vol 72 (10) ◽  
pp. 1479-1486 ◽  
Author(s):  
Gyeong Bok Jung ◽  
Sung Wook Kang ◽  
Gi-Ja Lee ◽  
Dohyun Kim
Keyword(s):  
Raman Spectroscopy ◽  
Cerebral Ischemia ◽  
Brain Tissue ◽  
Biochemical Characterization ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Principal Component ◽  
Normal Brain ◽  
Cerebral Ischemia Reperfusion ◽  
The Brain

Cerebral ischemic stroke is one of the most common neurodegenerative conditions characterized by cerebral infarction, death of the brain tissue, and loss of brain function. Cerebral ischemia-reperfusion injury is the tissue damage caused when blood supply begins to the tissue after a period of ischemia or poor oxygen supply. In this study, we preliminarily investigated the biochemical changes in the brain hippocampal area, CA1, resulting from ischemia reperfusion and neuronal nitric oxide synthase (nNOS) inhibitor treatment in rats using Raman spectroscopy. A drastic spectral change was observed in the ischemia-reperfusion brain tissue; a strong dependency between the intensity of certain Raman bands was observed at the amide positions of 1276 and 1658 cm−1 and at the lipid positions of 1300 and 1438 cm−1. The spectrum of nNOS inhibitor-treated brain tissue was similar to that of the normal brain tissue, indicating that the nNOS inhibitor could protect the brain against excessive production of NO and biochemical processes dependent on it. Principal component analysis (PCA) precisely identified three classes of tissues: normal; ischemic; and nNOS inhibitor-treated. Therefore, we suggest that quantitative analysis of the changes in the brain tissue by using Raman spectroscopy with multivariate statistical technique could be effective for evaluating neuronal injury and drug effects.

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