Surface electronic states mediate concerted electron and proton transfer at metal nanoscale interfaces for catalytic hydride reduction of -NO2 to -NH2.

Concerted electron and proton transfer is a key step for the reversible conversion of molecular hydrogen in both heterogeneous nanocatalysis and metalloenzyme catalysis. However, its activation mechanism involving electron and proton transfer kinetics remains elusive. With the most widely used catalytic hydride reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) as a model reaction, we evaluate the catalytic activity of noble metal nanoparticles (NPs) trapped in porous silica in aqueous NaBH4 solution. By virtue of a novel combination of catalyst design, reaction kinetics, isotope labeling, and multiple spectroscopic techniques, the real catalytic site for the conversion of -NO2 to -NH2 is identified to be the water-hydroxyl transition metal complex, which could further react with NaBH4 to form a new triangular configuration metal complex of H3B-water-hydroxyl with dynamic features. It yields an ensemble of surface electronic states (SESs) though space overlapping of p orbitals of one B and several O atoms (including the O atoms of 4-NP), which could act as an alternative channel for concerted electron and proton transfer. This work highlights the critical role of the conceptual SESs model in heterogeneous catalysis to tune the chemical reactivity and also sheds light on the intricate working of the [FeFe]-hydrogenases.

Mechanisms of an increased level of serum iron in gamma-irradiated mice.

The potential mechanisms underlying the increase in serum iron concentration in gamma-irradiated mice were studied. The gamma irradiation dose used was 4 Gy, and cobalt-60 ((60)Co) source was used for the irradiation. The dose rate was 0.25 Gy/min. In the serum of irradiated mice, the concentration of ferrous ions decreased, whereas the serum iron concentration increased. The concentration of ferrous ions in irradiated mice returned to normal at 21 day post-exposure. The concentration of reactive oxygen species in irradiated mice increased immediately following irradiation but returned to normal at 7 day post-exposure. Serum iron concentration in gamma-irradiated mice that were pretreated with reduced glutathione was significant lower (p < 0.01) than that in mice exposed to gamma radiation only. However, the serum iron concentration was still higher than that in normal mice (p < 0.01). This change was biphasic, characterized by a maximal decrease phase occurring immediately after gamma irradiation (relative to the irradiated mice) and a recovery plateau observed during the 7th and 21st day post-irradiation, but serum iron recovery was still less than that in the gamma-irradiated mice (4 Gy). In gamma-irradiated mice, ceruloplasmin activity increased and serum copper concentration decreased immediately after irradiation, and both of them were constant during the 7th and 21st day post-irradiation. It was concluded that ferrous ions in irradiated mice were oxidized to ferric ions by ionizing radiation. Free radicals induced by gamma radiation and ceruloplasmin mutually participated in this oxidation process. The ferroxidase effect of ceruloplasmin was achieved by transfer of electrons from ferrous ions to cupric ions.

Multidisciplinary diagnosis and treatment nutritional support intervention for gastrointestinal tumor radiotherapy: Impact on nutrition and quality of life.

BACKGROUND: Gastrointestinal tumors are a major cause of cancer-related deaths and have become a major public health problem. This study aims to provide a scientific basis for improving clinical treatment effects, quality of life, and prognosis of patients with gastrointestinal tumors. AIM: To explore the clinical effect of the multidisciplinary diagnosis and treatment (MDT) nutrition intervention model on patients with gastrointestinal tumors. METHODS: This was a case control study which included patients with gastrointestinal tumors who received radiotherapy at the Department of Oncology between January 2021 and January 2023. Using a random number table, 120 patients were randomly divided into MDT and control groups with 60 patients in each group. To analyze the effect of MDT on the nutritional status and quality of life of the patients, the nutritional status and quality of life scores of the patients were measured before and after the treatment. RESULTS: Albumin (ALB), transferrin (TRF), hemoglobin (Hb), and total protein (TP) levels significantly decreased after the treatment. The control group had significantly lower ALB, TRF, Hb, and TP levels than the MDT group, and the differences in these levels between the two groups were statistically significant (P < 0.05). After the treatment, the MDT group had significantly more well-nourished patients than the control group (P < 0.05). The quality of life total score, somatic functioning, role functioning, and emotional functioning were higher in the MDT group than in the control group. By contrast, pain, fatigue, nausea, and vomiting scores were lower in the MDT group than in the control group (P < 0.05). CONCLUSION: MDT nutritional intervention model effectively improves the nutritional status and quality of life of the patients. The study provides a rigorous theoretical basis for improving the prognosis of cancer patients. In the future, we intend to provide additional treatment methods for improving the quality of life of patients with cancer.

Identifying the Epitopes of Bacillus thuringiensis Cry2Aa Toxin Involved in Cadherin Interaction by a Monoclonal Antibody.

Antibodies are a useful tool for assistance to map the binding epitopes in Bacillus thuringiensis Cry toxins and their receptors, and even determine how receptors promote toxicity. In this work, a monoclonal antibody (mAb-1D2) was produced by the hybridoma cell line raised against Cry2Aa toxins, with a half inhibition concentration (IC50) of 9.16 µg/mL. The affinity constant of two recombinant toxin-binding fragments derived from Helicoverpa armigera and Plutella xylostella cadherin-like protein (HaCad-TBR or PxCad-TBR) to Cry2Aa toxin was measured to be 1.21 µM and 1.24 µM, respectively. Competitive ELISA showed that mAb-1D2 competed with HaCad-TBR or PxCad-TBR binding to Cry2Aa. Meanwhile, the toxicity of the Cry2Aa toxin to the H. armigera and P. xylostella larvae were greatly reduced when the toxin was mixed with mAb-1D2, which indicated that cadherin may play an important functional role in the toxicity of Cry2Aa. After transforming mAb-1D2 to a single-chain variable fragment (scFv), the hot spot residues of Cry2Aa with 1D2-scFv, PxCad-TBR, and HaCad-TBR were analyzed by molecular docking. It was demonstrated that the hot spot residues of Cry2Aa involving with 1D2-scFv interaction were mainly in Domain II, and some residues in Domain I. Moreover, mAb-1D2 and the two cadherin fragments shared the common hot spot residues on Cry2Aa, which could explain mAb-1D2 inhibited Cry2Aa binding with cadherin fragments. This monoclonal antibody could be a useful tool for identifying the binding epitopes between Cry2Aa and cadherin, and even assist to analyze the roles of cadherin in Cry2Aa toxicity.

ASPM facilitates colorectal cancer cells migration and invasion by enhancing ß-catenin expression and nuclear translocation.

Increased abnormal spindle-like microcephaly (ASPM) expression has been linked to clinical stage and poor prognosis in cancers, but the molecular mechanisms by which ASPM promotes cell metastasis in colorectal cancer (CRC) has not been identified. This study showed that the abilities of cell migration, invasion, and epithelial-mesenchymal transition (EMT) were attenuated in ASPM-deficient CRC cell lines. Furthermore, we reported that attenuation of ASPM expression inhibited CRC cell metastasis in vivo. Additionally, the expression of ASPM was positively correlated with ß-catenin level in CRC tissues. Mechanistically, ASPM can upregulate ß-catenin transcription by stimulating the ß-catenin promoter and enhancing the nuclear translocation of ß-catenin in CRC cells, which leads to the activation of the Wnt/ß-catenin pathway. Finally, we showed that ASPM effectively induced CRC cell migration and invasion in a ß-catenin-dependent manner.

Caged structural water molecules emit tunable brighter colors by topological excitation.

Intrinsically, free water molecules are a colourless liquid. If it is colourful, why and how does it emit the bright colours? We provided direct evidence that when water was trapped into the sub-nanospace of zeolites, the structural water molecules (SWs) exhibited strong tunable photoluminescence (PL) emissions from blue to red colours with unprecedented ultra-long lifetimes up to the second scale at liquid nitrogen temperature. Further controlled experiments and combined characterizations by time-resolved steady-state and ultra-fast femtosecond (fs) transient optical spectroscopy showed that the singly adsorbed hydrated hydroxide complex {OH-·H2O} as SWs in the confined nanocavity is the true emitter centre, whose PL efficiency strongly depends on the type and stability of the SWs, which is dominated by H-bond interactions, such as the solvent effect, pH value and operating temperature. The emission of SWs exhibits the characteristic of topological excitations (TAs) due to the many-body quantum electron correlations in confined nanocavities, which differs from the local excitation of organic chromophores. Our model not only elucidates the origin of the PL of metal nanoclusters (NCs), but also provides a completely new insight to understand the nature of heterogeneous catalysis and interface bonding (or state) at the molecule level, beyond the metal-centred d band theory.

Separation of anthocyanins from Perilla frutescens by high speed countercurrent chromatography.

OBJECTIVE: To develop an efficient method for the separation of anthocyanins from Perilla frutescens. METHODS: Freeze-dried Perilla frutescens was extracted with 1% HCl. After purified by Amberlite XAD-7 column chromatography, the bioactive anthocyanins were separated by high-speed countercurrent chromatography (HSCCC). The structures of the compounds were elucidated by 1H- and 13C-NMR spectroscopy. RESULTS: When the HSCCC separation was performed with a two-phase solvent system composed of n-butanol-tert-butyl methyl ether-acentonitrile-water (2:2:1:5 + 0.1% TFA) by eluting the mobile phase at a flow rate of 3.0 mL/min and a revolution speed of 800 r/min, 10.1 mg malonylshisonin and 8.6 mg shisonin were obtained from 1.0 g of the XAD-7 extract. The purities of malonylshisonin and shisonin were 96.7% and 97.5%, respectively. CONCLUSION: HSCCC is a fast and efficient technique to prepare pure malonylshisonin and shisonin from Perilla frutescens.

Protective effect of ginsenoside Rb1 on beta-amyloid protein(1-42)-induced neurotoxicity in cortical neurons.

The effects of ginsenosides were thought to prevent neurodegenerative processes associated with aging. The accumulation of beta-amyloid protein (Abeta) within the brain is one of the pathological hallmarks of Alzheimer's disease (AD). There is no one effective treatment of AD. To investigate the effects of ginsenoside Rb1 (GRb1) on neuronal damage induced by Abeta and potential mechanisms of the effects of GRb1 in vitro, morphological observation and biochemical analysis combining primary cultured neurons were adopted. A positive control was pre-treated with Trolox. Neurons that were treated with Abeta 1-42 (2 muM) were shrunken perikaryon with loss of neurite processes; the survival rate of neurons decreased almost to 50% (p<0.01). Lactate dehydrogenase (LDH) release, malondialdehyde (MDA) product and superoxide dismutase (SOD) activity level all increased obviously (p<0.01 or p<0.05). However, neurons pre-treated with GRb1 (0.1, 1 and 10 muM) or Trolox (10 muM) had a survival rate increase compared with neurons treated with Abeta alone; LDH release and MDA product decreased distinctly, and the increase in SOD activity in Abeta-treated neurons was attenuated evidently (p<0.01 or p<0.05). Thus, we conclude that GRb1 exerted neuroprotection obviously. GRb1 protected neurons against the toxicity of Abeta, most likely through an antioxidant pathway. GRb1 could be useful neuroprotective agents of AD.

[Survival and prognostic factors in resected satellite-nodule T4 non-small cell lung cancer].

OBJECTIVE: To study the survival and prognostic implication in surgically resected satellite-nodule T4 (T4 satellite) non-small cell lung cancer (NSCLC). METHODS: From January 1995 to March 2005, the complete resection was performed to 42 patients with NSCLC who were postoperatively identified as pathologic-stage T4 satellite. Survival and associations between clinicopathological parameters and prognosis were analyzed. Thirty-two patients with pathologic stage local-invasion T4 (T4 invasion) NSCLC who underwent resection at the same time were also analyzed. RESULTS: The 1-, 3- and 5-year survival was 76.2%, 57.1% and 46.0% for patients with T4 satellite, while 62.3%, 31.5% and 20.0% for patients with T4 invasion. There was a significant higher survival in T4 satellite group when compared to that in T4 invasion group (P < 0.05). Furthermore, patients with T4 satellite N0M0 got a better survival than those with T4 satellite N1-2M0, T4 invasion N0M0 and T4 invasion N1 -2M0 (P < 0.05). For patients with T4 satellite, univariate analysis showed that histology, main tumor size, lymph node status and adjuvant chemotherapy were linked with survival, while main tumor size, lymph node status and adjuvant chemotherapy served as the independent prognostic factors with multivariate analysis. CONCLUSIONS: Patients with completely resected T4 satellite NSCLC have a better prognosis than those with T4 invasion. Main tumor size over 3 cm, lymph node metastasis or no adjuvant chemotherapy means an unfavorable prognosis.

[Vasoactive intestinal peptide attenuates apoptosis and iNOS protein expression induced by cerebral ischemia in the rat].

OBJECTIVE: To explore the neuroprotective action of vasoactive intestinal peptide (VIP) on ischemia and reperfusion in the rat. METHODS: VIP was given via intracerebroventriclar injection after a 2 hour transient middle cerebral artery occlusion using filament model. The infarct volume was investigated with TTC stain. Apoptosis in the ischemic boundary zone were evaluated with TUNEL stain. Western blotting were used to analyze the iNOS protein expression as well. RESULTS: After VIP injection, the relative infarct volume of rats was significantly reduced by approximately 28% campared to that of the control groups at 1 day (P < 0.05). The number of TUNEL positive cells was significantly decreased in the ischemic boundary zone, and then the expression of iNOS was remarkablely decreased as well (P < 0.05). CONCLUSION: VIP has a neuroprotective effect on cerebral ischemia and reperfusion. The mechanism seems to involve decreasing the apoptosis and down-regulating the iNOS expression.

[Internalization of beta amyloid protein in primary cultured cortical neurons in mouse].

OBJECTIVE: To observe the internalization of beta-amyloid protein (Abeta) in primary cultured neurons and effect of astrocyte on it. METHODS: The purified cortical neurons of mouse were cultured for 14 d, and were divided into a control group and an Abeta group. Each group was further divided into 3 subgroups. The neurons and 3 different concentration fluorescein or Abeta1-42-fluo were co-incubated for 24 h. The internalization of Abeta and the location of Abeta in subcellular structure were examined by the laser scanning confocal microscope combined with the image analysis method directly or after immunofluorescence staining. Neurons and astrocytes were co-cultured for 14 d. The cultured neurons and astrocytes were divided into a control group and a Abeta group. The cultures were treated with 200 nmol/L fluorescein or 200 nmol/L Abeta1-42-fluo for 24 h respectively. The effect of astrocyte on the internalization was analyzed by the above method. RESULTS: There were no fluorescent granules within neurons in every fluorescein group. The purified cortical neurons could internalize 100 nmol/L, or 200 nmol/L Abeta1-42-fluo in 24 h. The fluorescent granules of Abeta1-42 distributed within perikaryon and processes. The internalization was related to the concentration of Abeta. The part of Abeta was located in the lysosome of neurons indicated by immunofluorescence staining. Compared with the purified neurons, the neurons co-cultured with the astrocytes internalized Abeta increased in the internalization of Abeta. There was significant difference between the purified neurons and the co-cultured neurons with astrocytes (P<0.05). CONCLUSION: Neurons could internalize the proper concentration of Abeta. Astrocyte might facilitate the internalization of Abeta in neurons.

The effects of combined selenium nanoparticles and radiation therapy on breast cancer cells in vitro.

Radiosensitizers that increase cancer cell radio-sensitivity can enhance the effectiveness of irradiation and minimize collateral damage. Nanomaterial has been employed in conjunction with radiotherapy as radiosensitizers, due to its unique physicochemical properties. In this article, we evaluated selenium nanoparticles (Nano-Se) as a new radiosensitizer. Nano-Se was used in conjunction with irradiation on MCF-7 breast cancer cells, and efficacy and mechanisms of this combined treatment approach were evaluated. Nano-Se reinforced the toxic effects of irradiation, leading to a higher mortality rate than either treatment used alone, inducing cell cycle arrest at the G2/M phase and the activation of autophagy, and increasing both endogenous and irradiation-induced reactive oxygen species formation. These results suggest that Nano-Se can be used as an adjuvant drug to improve cancer cell sensitivity to the toxic effects of irradiation and thereby reduce damage to normal tissue nearby.

Activation of α7 nicotinic acetylcholine receptor alleviates Aß1-42-induced neurotoxicity via downregulation of p38 and JNK MAPK signaling pathways.

Amyloid ß peptide 1-42 (Aß1-42) could induce cognitive deficits through oxidative stress, inflammation, and neuron death in Alzheimer's disease (AD). MAPK pathways have been thought to mediate Aß1-42-induced neuroinflammation responses, neuron death and cognitive decline in AD. The α7 nicotinic acetylcholine receptor (α7nAChR) exerts a neuroprotective effect. However, whether α7nAChR alleviates Aß1-42-induced neurotoxicity through MAPKs (p38, ERK, JNK) in vivo remains unclear. In our study, memory was assessed in C57BL/6 mice using a Y-maze test. Cell death was assessed by Nissl and Hoechst staining and Bax, Bcl-2, Caspase 3, and Cytochrome C levels using Western blotting. Oxidative stress was assayed by superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA) levels. Inflammation was examined with GFAP and Iba1 using immunohistochemistry. The Aß degrading enzymes insulin degrading enzyme (IDE) and neprilysin (NEP) were tested using Western blotting. We found that activating α7nAChR or inhibiting p38 or JNK pathway alleviated Aß1-42-induced cognitive deficits and neuron loss and death by reducing oxidative stress. In addition, activating α7nAChR or inhibiting p38 or JNK pathway also reduced inflammation, which was observed as reduced GFAP and Iba1 levels with different effects on Aß degrading enzymes. Finally, we found that the activation of α7nAChR led to the downregulation of pp38 and pJNK levels. Conversely, the inhibition of p38 or JNK resulted in the upregulation of α7nAChR levels in the hippocampus and cortex. Our data indicate that the activation of α7nAChR alleviates Aß1-42-induced neurotoxicity, and this protective effect might act through the downregulation of p38 and JNK MAPKs.

The p38 mitogen activated protein kinase regulates ß-amyloid protein internalization through the α7 nicotinic acetylcholine receptor in mouse brain.

Alzheimer's disease (AD) is one of the most devastating neurodegenerative disorders. Intracellular ß-amyloid protein (Aß) is an early event in AD. It induces the formation of amyloid plaques and neuron damage. The α7 nicotinic acetylcholine receptor (α7nAChR) has been suggested to play an important role in Aß caused cognition. It has high affinity with Aß and could mediate Aß internalization in vitro. However, whether in mouse brain the p38 MAPK signaling pathway is involved in the regulation of the α7nAChR mediated Aß internalization and their role in mitochondria remains little known. Therefore, in this study, we revealed that Aß is internalized by cholinergic and GABAergic neurons. The internalized Aß were found deposits in lysosomes/endosomes and mitochondria. Aß could form Aß-α7nAChR complex with α7nAChR, activates the p38 mitogen activated protein kinase (MAPK). And the increasing of α7nAChR could in return mediate Aß internalization in the cortex and hippocampus. In addition, by using the α7nAChR agonist PNU282987, the p38 phosphorylation level decreases, rescues the biochemical changes which are tightly associated with Aß-induced apoptosis, such as Bcl2/Bax level, cytochrome c (Cyt c) release. Collectively, the p38 MAPK signaling pathway could regulate the α7nAChR-mediated internalization of Aß. The activation of α7nAChR or the inhibition of p38 MAPK signaling pathway may be a beneficial therapy to AD.

The p38 mitogen-activated protein kinase signaling pathway is involved in regulating low-density lipoprotein receptor-related protein 1-mediated ß-amyloid protein internalization in mouse brain.

Alzheimer's disease (AD) is one of the most common neurodegenerative diseases. Recently, increasing evidence suggests that intracellular ß-amyloid protein (Aß) alone plays a pivotal role in the progression of AD. Therefore, understanding the signaling pathway and proteins that control Aß internalization may provide new insight for regulating Aß levels. In the present study, the regulation of Aß internalization by p38 mitogen-activated protein kinases (MAPK) through low-density lipoprotein receptor-related protein 1 (LRP1) was analyzed in vivo. The data derived from this investigation revealed that Aß1-42 were internalized by neurons and astrocytes in mouse brain, and were largely deposited in mitochondria and lysosomes, with some also being found in the endoplasmic reticulum. Aß1-42-LRP1 complex was formed during Aß1-42 internalization, and the p38 MAPK signaling pathway was activated by Aß1-42 via LRP1. Aß1-42 and LRP1 were co- localized in the cells of parietal cortex and hippocampus. Furthermore, the level of LRP1-mRNA and LRP1 protein involved in Aß1-42 internalization in mouse brain. The results of this investigation demonstrated that Aß1-42 induced an LRP1-dependent pathway that related to the activation of p38 MAPK resulting in internalization of Aß1-42. These results provide evidence supporting a key role for the p38 MAPK signaling pathway which is involved in the regulation of Aß1-42 internalization in the parietal cortex and hippocampus of mouse through LRP1 in vivo.

Methemoglobin-Based Biological Dose Assessment for Human Blood.

Methemoglobin is an oxidative form of hemoglobin in erythrocytes. The authors' aim was to develop a new biological dosimeter based on a methemoglobin assay. Methemoglobin in peripheral blood (of females or males) that was exposed to a Co source (0.20 Gy min) was quantified using an enzyme-linked immunosorbent assay. The dose range was 0.5-8.0 Gy. In a time-course experiment, the time points 0, 0.02, 1, 2, 3, 7, 15, 21, and 30 d after 4-Gy irradiation of heparinized peripheral blood were used. Methemoglobin levels in a lysed erythrocyte pellet from the irradiated blood of females and males increased with the increasing dose. Methemoglobin levels in female blood irradiated with γ-doses more than 4 Gy were significantly higher than those in male samples at the same doses. Two dose-response relations were fitted to the straight line: one is with the correlation coefficient of 0.98 for females, and the other is with the correlation coefficient of 0.99 for males. The lower limit of dose assessment based on methemoglobin is about 1 Gy. Methemoglobin levels in blood as a result of auto-oxidation increase after 7-d storage at -20 °C. The upregulation of methemoglobin induced by γ-radiation persists for ∼3 d. The absorbed doses that were estimated using the two dose-response relations were close to the actual doses. The results suggest that methemoglobin can be used as a rapid and accurate biological dosimeter for early assessment of absorbed γ-dose in human blood.

Enhancement of radiotherapy by ceria nanoparticles modified with neogambogic acid in breast cancer cells.

Radiotherapy is one of the main strategies for cancer treatment but has significant challenges, such as cancer cell resistance and radiation damage to normal tissue. Radiosensitizers that selectively increase the susceptibility of cancer cells to radiation can enhance the effectiveness of radiotherapy. We report here the development of a novel radiosensitizer consisting of monodispersed ceria nanoparticles (CNPs) covered with the anticancer drug neogambogic acid (NGA-CNPs). These were used in conjunction with radiation in MCF-7 breast cancer cells, and the efficacy and mechanisms of action of this combined treatment approach were evaluated. NGA-CNPs potentiated the toxic effects of radiation, leading to a higher rate of cell death than either treatment used alone and inducing the activation of autophagy and cell cycle arrest at the G2/M phase, while pretreatment with NGA or CNPs did not improve the rate of radiation-induced cancer cells death. However, NGA-CNPs decreased both endogenous and radiation-induced reactive oxygen species formation, unlike other nanomaterials. These results suggest that the adjunctive use of NGA-CNPs can increase the effectiveness of radiotherapy in breast cancer treatment by lowering the radiation doses required to kill cancer cells and thereby minimizing collateral damage to healthy adjacent tissue.

Development of serum zinc as a biological dosimeter in mice.

PURPOSE: To develop a new biological dosimeter based on serum zinc concentration. MATERIALS AND METHODS: Male mice (8 weeks old) were exposed to different doses (0, 1.0, 2.0, 4.0, or 8.0 Gy) of gamma rays from a (60)Co source. Blood was then collected from the orbital area of these mice, and the serum zinc concentration was detected using the 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol colorimetric method. The data were analyzed using one-way analysis of variance. RESULTS: The serum zinc concentration in the irradiated mice decreased with increasing dose. Two dose-response relationships fitted to the linear quadratic curve were obtained: One immediately after exposure (y = 0.010x(2) - 0.133x + 0.663, r = 0.983) and the other on the seventh day after exposure (y = 0.008x(2) - 0.127x + 0.695, r = 0.990). The serum zinc concentration continued to decrease until 21 days after exposure. The absorbed doses estimated using both dose-response relationships were close to the actual doses. CONCLUSIONS: Serum zinc is a quick, effective, and sensitive biomarker for early biological doses assessment of mice irradiated by gamma radiation.

The effects of valsartan on cognitive deficits induced by aluminum trichloride and d-galactose in mice.

OBJECTIVES: Valsartan has been reported to reduce brain beta-amyloid protein levels and improve spatial learning in the Tg2576 transgenic mouse model of Alzheimer's disease (AD). However, the exact mechanism of neuroprotective effects of valsartan has not been properly studied especially in cholinergic function and oxidative damage, the essential factors that undergo impairment in AD. Therefore, the present study examined the effects of valsartan on memory impairment, cholinergic dysfunction, and oxidative stress in aluminum trichloride (AlCl3) and d-galactose (d-gal)-induced experimental sporadic dementia of Alzheimer's type. METHODS: Valsartan was administered intragastrically (i.g.) (20 mg/kg/day) for 60 days after mice were given AlCl3 (10 mg/kg/day) and d-gal (150 mg/kg/day) intraperitoneally (i.p.) once daily for 90 days. Then, memory function was evaluated by Morris water maze test. Acetylcholinesterase (AChE), superoxide dismutases (SOD) and glutathione peroxidase (GSH-Px) activities and malondialdehyde (MDA) level in cortex and hippocampus were also assessed with biochemical technique. RESULTS: Chronic administration of valsartan not only improved learning and memory but also restored the elevation of AChE activity induced by AlCl3 and d-gal in cortex and hippocampus. In addition, valsartan significantly restored SOD and GSH-Px activities and reduced MDA level in cortex and hippocampus indicating attenuation of oxidative stress. DISCUSSION: Our results indicate that valsartan prevents AlCl3- and d-gal-induced cognitive decline partly to restore cholinergic function and attenuate oxidative damage. These findings further support the potential of valsartan to be used in AD treatment.

The effects of perindopril on cognitive impairment induced by d-galactose and aluminum trichloride via inhibition of acetylcholinesterase activity and oxidative stress.

Preclinical and clinical studies indicate involvement of renin angiotensin system (RAS) in memory functions. However, exact role of RAS in cognition is still ambiguous. The present study investigated the effects of perindopril on dementia of Alzheimer's type induced by d-galactose (d-gal) and aluminum trichloride (AlCl3). Perindopril, an angiotensin converting enzyme inhibitor, was administered intragastrically (0.5mg/kg/day) for 60days after mice were given d-gal (150mg/kg/day) and AlCl3 (10mg/kg/day) intraperitoneally for 90days. Then, memory function was evaluated by Morris water maze test. The biochemical studies were conducted in cerebral cortex and hippocampus of mouse brain after the behavioral studies. d-Gal and AlCl3 caused significant memory impairment along with significant elevation of acetylcholinesterase (AChE) activity in cerebral cortex and hippocampus. Further, a significant reduction of superoxide dismutases (SOD) and glutathione peroxidase (GSH-Px) activities, and elevation of malondialdehyde (MDA) level in cerebral cortex and hippocampus were observed. Perindopril not only improved cognitive impairment but also restored the elevation of AChE activity induced by d-gal and AlCl3. In addition, perindopril significantly increased SOD and GSH-Px activities, reduced MDA level in cerebral cortex and hippocampus. Taken together, the above findings indicate that perindopril improves learning and memorizing probably by restoring cholinergic function and attenuating oxidative damage.