Mechanism of cellular 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction

Ellagic acid, a polyphenolic compound, selectively induces ROS-mediated apoptosis in cancerous B-lymphocytes of CLL patients by directly targeting mitochondria

To investigate the effects ofellagic acid (EA) on the cytotoxicity, B-lymphocytes isolated from CLL patients and healthy individuals. Flow cytometric assay was used to measure the percentage of apoptosis versus necrosis, intracellular active oxygen radicals (ROS), mitochondrial membrane potential (MMP) and the caspase-3 activity and then mitochondria were isolated from both groups B-lymphocytes and parameters of mitochondrial toxicity was investigated. Based on our results EA decreased the percentage of viable cells and induced apoptosis. EA increased ROS formation, mitochondria swelling, MMP decrease and cytochrome c release in mitochondria isolated from CLL BUT NOT healthy B-lymphocytes while pre-treatment with cyclosporine A and Butylated hydroxyl toluene (BHT) prevented these effects. Our results suggest that EA can act as an anti cancer candidate by directly and selectively targeting mitochondria could induce apoptosis through mitochondria pathway with increasing ROS production which finally ends in cytochrome c release, caspase 3 activation and apoptosis in cancerous B-lymphocytes isolated from CLL patients.

Cell suspension concentration monitoring by using a miniaturized serial high frequency SAWR sensor

In this paper, a miniaturized cell suspension concentration monitoring method was investigated. The sensing unit was a carbon screen-printed electrode (CSPE) in serial with a 433MHz vacuum-packaged surface acoustic wave resonator (SAWR). SAWR provided a stable and high operating frequency, which helps to keep the stability and sensitivity of the monitoring system. Living cells suspensions in different concentrations were prepared and dropcast on CSPE. Frequency responses of the sensor were recorded. Cell quantity variation within the same culture media volume changed the dielectric properties of CSPE and finally affected the SAWR frequency. SAWR frequency declined with the decrease of cell concentration. The proposed sensor provided high sensitivity and remarkable stability for the cell suspensions.

Microglial Inhibitory Mechanism of Coenzyme Q10 Against Aβ (1-42) Induced Cognitive Dysfunctions: Possible Behavioral, Biochemical, Cellular, and Histopathological Alterations

Rationale: Alzheimer’s disease (AD) is a debilitating disease with complex pathophysiology. Amyloid beta (Aβ) (1-42) is a reliable model of AD that recapitulates many aspects of human AD.

Objective: The intent of the present study was to investigate the neuroprotective potential of Coenzyme Q10 (CoQ10) and its modulation by minocycline (microglial inhibitor) against Aβ (1-42) induced cognitive dysfunction in rats.

Method: Intrahippocampal (i.h.) Aβ (1-42) (1 μg/μl; 4μl/site) were administered followed by drug treatment with galantamine (2 mg/kg), CoQ10 (20 and 40 mg/kg), minocycline (50 and 100 mg/kg) and their combinations for a period of 21 days. Various neurobehavioral parameters followed by biochemical, acetylcholinesterase (AChE) level, proinflammatory markers (TNF-α), mitochondrial respiratory enzyme complexes (I-IV) and histopathological examinations were assessed.

Results: Aβ (1-42) administration significantly impaired cognitive performance in Morris water maze (MWM) performance test, causes oxidative stress, raised AChE level, caused neuroinflammation, mitochondrial dysfunction and histopathological alterations as compared to sham treatment. Treatment with CoQ10 (20 and 40 mg/kg) and minocycline (50 and 100 mg/kg) alone for 21 days significantly improved cognitive performance as evidenced by reduced transfer latency and increased time spent in target quadrant (TSTQ), reduced AChE activity, oxidative damage (reduced LPO, nitrite level and restored SOD, catalase and GHS levels), TNF-α level, restored mitochondrial respiratory enzyme complex (I, II, III, IV) activities and histopathological alterations as compared to Aβ (1-42) treated animals. Further, combinations of minocycline (50 and 100 mg/kg) with CoQ10 (20 and 40 mg/kg) significantly modulates the protective effect of CoQ10 dose dependently as compared to their effect alone.

Conclusion: The present study suggests that the neuroprotective effect of CoQ10 could be due to its microglia inhibitory mechanism along with its mitochondrial restoring and anti-oxidant properties.

Ameliorative effect of naringin against doxorubicin-induced acute cardiac toxicity in rats

CONTEXT

Doxorubicin (Dox) is one of the most active chemotherapeutic agents used to treat various types of cancers. Its clinical utility is compromised due to fatal cardiac toxicity characterized by an irreversible cardiomyopathy.

OBJECTIVE

This study evaluates the cardioprotective potential of naringin (NR) against Dox-induced acute cardiac toxicity in rats.

MATERIALS AND METHODS

Male Wistar rats were randomly divided into five groups. NR (50 and 100 mg/kg) was administered intraperitoneally (i.p.) daily from 0 to 14 d. Doxorubicin (15 mg/kg, i.p.) was given as a single dose on the 10th day. On the 14th day, all animals were sacrificed and oxidative stress parameters that include malondialdehyde (MDA), glutathione (GSH) level, superoxide dismutase (SOD), catalase (CAT) activities, and all mitochondrial complexes (I-IV) activities were evaluated along with histopathological studies of the heart.

RESULTS

Doxorubicin-induced cardiotoxicity was confirmed by increased (p < 0.05) MDA, decreased (p < 0.05) GSH levels, SOD, and CAT activities, mitochondrial complexes (I-IV) activities in the heart tissue. NR (100 mg/kg) showed cardioprotection as evident from significant decreased MDA (p < 0.001) level, raised (p < 0.001) GSH level, SOD and CAT activities and increased mitochondrial complexes I (p < 0.01), II (p < 0.001), III (p < 0.001), and IV (p < 0.05) activities. Further, Dox-induced cardiotoxicity was confirmed by histopathological studies. These obtained results indicated the protective role of NR against Dox-induced cardiac toxicity in rats.

CONCLUSION

NR can be used in combination with Dox due to its high cardioprotective effect against Dox-induced cardiomyopathy.

Determination of cytotoxicity of traditional Chinese medicine herbs, Rhizoma coptidis, Radix scutellariae, and Cortex phellodendri, by three methods

BACKGROUND

Many herbs are used in traditional Chinese medicine TCM) for treatment of infections but their properties, in particular, their effects on normal cells have received little attention. This study investigated the cytotoxic properties of three TCM herbs with potential use in prevention and treatment of ocular infections, including Acanthamoeba keratitis.

METHOD

The study investigated cytotoxic effects of the herbal extracts of Rhizoma coptidis, Radix scutellariae, and Cortex phellodendri on human corneal epithelial cells using trypan blue staining, MTT production, and flow cytometry. Differences between herbs were determined using repeated measures one-way analysis of variance, followed by paired t-tests where appropriate.

RESULTS

These three herbs appeared to lack cytotoxicity when tested with trypan blue and MTT, but flow cytometry revealed that R. coptidis led to cell membrane damage.

CONCLUSION

Lack of cytotoxicity of R. scutellariae and C. phellodendri extracts suggest that these are potentially suitable for use in ocular preparations. Only flow cytometry was able to accurately predict cytotoxic effects of extracts of TCM herbs on HCEC, demonstrating the importance of using a sensitive method of detection of cytotoxicity.

Moderate-Intensity Physical Exercise Protects Against Experimental 6-Hydroxydopamine-Induced Hemiparkinsonism Through Nrf2-Antioxidant Response Element Pathway

INTRODUCTION

Exercise improves the motor symptoms of patients with Parkinson disease in a palliative manner. Existing evidence demonstrates that exercise induces neuroprotection based on the neurotrophic properties. We investigated the effect of exercise on mitochondrial physiology and oxidative stress in an animal model of hemiparkinsonism.

METHODS

C57BL/6 mice completed a 6-week exercise program on a treadmill. We injected 6-hydroxydopamine (6-OHDA; 4 μg/2 μl) into the midstriatum. The animals progressively developed bradykinesia and R(-)-apomorphine-induced rotations that were attenuated by exercise. Transcriptional activation of protective genes is mediated by the antioxidant response element (ARE). Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) binds to ARE. We investigated the Nrf2-ARE pathway in the striatum of animals.

RESULTS

Exercise protected 6-OHDA-induced loss of tyrosine hydroxylase immunolabeling and activated the Nrf2-ARE pathway in the nigrostriatal pathway. Exercise stimulated mitochondrial biogenesis in the striatum of animals that was more resistant to oxidant 6-OHDA and nitric oxide donor (±)-S-nitroso-N-acetylpenicillamine.

CONCLUSIONS

In mice, exercise activated Nrf2-ARE signaling in the nigrostriatal pathway that was protective against the development of hemiparkinsonism.

Neuronal copper homeostasis susceptibility by genetic defects in dysbindin, a schizophrenia susceptibility factor

Environmental factors and susceptible genomes interact to determine the risk of neurodevelopmental disorders. Although few genes and environmental factors have been linked, the intervening cellular and molecular mechanisms connecting a disorder susceptibility gene with environmental factors remain mostly unexplored. Here we focus on the schizophrenia susceptibility gene DTNBP1 and its product dysbindin, a subunit of the BLOC-1 complex, and describe a neuronal pathway modulating copper metabolism via ATP7A. Mutations in ATP7A result in Menkes disease, a disorder of copper metabolism. Dysbindin/BLOC-1 and ATP7A genetically and biochemically interact. Furthermore, disruption of this pathway causes alteration in the transcriptional profile of copper-regulatory and dependent factors in the hippocampus of dysbindin/BLOC-1-null mice. Dysbindin/BLOC-1 loss-of-function alleles do not affect cell and tissue copper content, yet they alter the susceptibility to toxic copper challenges in both mammalian cells and Drosophila. Our results demonstrate that perturbations downstream of the schizophrenia susceptibility gene DTNBP1 confer susceptibility to copper, a metal that in excess is a neurotoxin and whose depletion constitutes a micronutrient deficiency.

NMDA Receptors and Oxidative Stress Induced by the Major Metabolites Accumulating in HMG Lyase Deficiency Mediate Hypophosphorylation of Cytoskeletal Proteins in Brain From Adolescent Rats: Potential Mechanisms Contributing to the Neuropathology of This Disease

Neurological symptoms and cerebral abnormalities are commonly observed in patients with 3-hydroxy-3-methylglutaryl-CoA lyase (HMG lyase) deficiency, which is biochemically characterized by predominant tissue accumulation of 3-hydroxy-3-methylglutaric (HMG), 3-methylglutaric (MGA), and 3-methylglutaconic (MGT) acids. Since the pathogenesis of this disease is poorly known, the present study evaluated the effects of these compounds on the cytoskeleton phosphorylating system in rat brain. HMG, MGA, and MGT caused hypophosphorylation of glial fibrillary acidic protein (GFAP) and of the neurofilament subunits NFL, NFM, and NFH. HMG-induced hypophosphorylation was mediated by inhibiting the cAMP-dependent protein kinase (PKA) on Ser55 residue of NFL and c-Jun kinase (JNK) by acting on KSP repeats of NFM and NFH subunits. We also evidenced that the subunit NR2B of NMDA receptor and Ca(2+) was involved in HMG-elicited hypophosphorylation of cytoskeletal proteins. Furthermore, the antioxidants L-NAME and TROLOX fully prevented both the hypophosphorylation and the inhibition of PKA and JNK caused by HMG, suggesting that oxidative damage may underlie these effects. These findings indicate that the main metabolites accumulating in HMG lyase deficiency provoke hypophosphorylation of cytoskeleton neural proteins with the involvement of NMDA receptors, Ca(2+), and reactive species. It is presumed that these alterations may contribute to the neuropathology of this disease.

The role of multifunctional drug therapy against carbamate induced neuronal toxicity during acute and chronic phase in rats

The current study has been designed to examine the effect of multifunctional drug therapy on carbofuran induced acute (2.187 mg/kg, s.c.) and sub-acute (0.2187 mg/kg, s.c.) neurotoxicity in male wistar rats. Drug treatment which includes nimodipine (Ca(2+) channel blocker), diazepam, ropinirole (dopamine agonist) and GSPE (antioxidant) was started 2h after carbofuran administration. Morris water maze was employed for aiming spatial memory. Narrow beam walk and rotarod were employed for testing motor functions. Brain acetylcholinesterase activity, thiobarbituric acid reactive species, nitrite, reduced glutathione, catalase levels, and mitochondrial complexes were also estimated. Carbofuran treatment resulted in significant development of cognitive and motor functions manifested as impairment in learning and memory along with increased thiobarbituric acid reactive species, nitrite levels and decreased acetylcholinesterase activity, reduced glutathione, catalase levels, and mitochondrial complexes. The standard antidote therapy (atropine) was not able to provide neuroprotection but was able to provide symptomatic relief. The multifunctional drug therapy attenuated carbofuran induced cognitive and motor dysfunction, acetylcholinesterase activity and other biochemical parameters. The triple combination in sub-acute study may be avoided in future as two drug combinations provide adequate neuroprotection. Thus it can be concluded that standard antidotal therapy may not provide neuroprotection while the multifunctional drug therapy offers neuroprotection against carbofuran and may dramatically increase survival and life quality.

Toxicity study in blood and tumor cells of laser produced medicines for application in fabrics

Phenothiazine derivatives are non-antibiotics with antimicrobial, fungistatic and fungicidal effects. We exposed to a high energy UV laser beam phenothiazines solutions in water at 20mg/mL concentration to increase antibacterial activity of resulting mixtures. Compared to previous results obtained on bacteria, more research is needed about UV laser irradiated phenothiazines applications on cancer cell cultures to evidence possible anticancerous properties. Evaluation of the safety of the newly obtained photoproducts in view of use on humans is also needed. Due to expensive animal testing in toxicology and pressure from general public and governments to develop alternatives to in vivo testing, in vitro cell-based models are attractive for preliminary testing of new materials. Cytotoxicity screening reported here shows that laser irradiated (4h exposure time length) chlorpromazine and promazine are more efficient against some cell cultures. Interaction of laser irradiated phenothiazines with fabrics show that promethazine and chlorpromazine have improved wetting properties. Correlation of these two groups of properties shows that chlorpromazine appears to be more recommended for applications on tissues using fabrics as transport vectors. The reported results concern stability study of phenothiazines water solutions to know the time limits within which they are stable and may be used.

Low Doses of Camptothecin Induced Hormetic and Neuroprotective Effects in PC12 Cells

Hormetic response is an adaptive mechanism for a cell or organism surviving in an unfavorable environment. It has been an intriguing subject of researches covering a broad range of biological and medical disciplines, in which the underlying significance and molecular mechanisms are under intensive investigation. In the present study, we demonstrated that topoisomerase I inhibitor camptothecin (CPT), a potent anticancer agent, induced an obvious hormetic response in rat pheochromocytoma PC12 cells. Camptothecin inhibited PC12 cell growth at relative high doses as generally acknowledged while stimulated the cell growth by as much as 39% at low doses. Moreover, low doses of CPT protected the cells from hydrogen peroxide (H₂O₂)-induced cell death. Phosphoinositide 3-kinase (PI3K)/Akt and nuclear factor-E2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathways were reported playing pivotal roles in protecting cells from oxidative stress. We observed that these 2 pathways were upregulated by low doses of CPT, as evidenced by increased levels of phosphorylated PI3K, phosphorylated Akt, phosphorylated mammalian target of rapamycin, Nrf2, and HO-1; and abolishment of the growth-promoting and neuroprotective effects of CPT by LY294002, a PI3K inhibitor. These results suggest that the hormetic and neuroprotective effects of CPT at low doses on PC12 cells were attributable, at least partially, to upregulated PI3K/Akt and Nrf2/HO-1 pathways.

Naringenin Mitigates Iron-Induced Anxiety-Like Behavioral Impairment, Mitochondrial Dysfunctions, Ectonucleotidases and Acetylcholinesterase Alteration Activities in Rat Hippocampus

Studies demonstrated that the iron chelating antioxidant restores brain dysfunction induced by iron toxicity in animals. Earlier, we found that iron overload-induced cerebral cortex apoptosis correlated with oxidative stress could be protected by naringenin (NGEN). In this respect, the present study is focused on the mechanisms associated with the protective efficacy of NGEN, natural flavonoid compound abundant in the peels of citrus fruit, on iron induced impairment of the anxiogenic-like behaviour, purinergic and cholinergic dysfunctions with oxidative stress related disorders on mitochondrial function in the rat hippocampus. Results showed that administration of NGEN (50 mg/kg/day) by gavage significantly ameliorated anxiogenic-like behaviour impairment induced by the exposure to 50 mg of Fe-dextran/kg/day intraperitoneally for 28 days in rats, decreased iron-induced reactive oxygen species formation and restored the iron-induced decrease of the acetylcholinesterase expression level, mitochondrial membrane potential and mitochondrial complexes activities in the hippocampus of rats. Moreover, NGEN was able to restore the alteration on the activity and expression of ectonucleotidases such as adenosine triphosphate diphosphohydrolase and 5'-nucleotidase, enzymes which hydrolyze and therefore control extracellular ATP and adenosine concentrations in the synaptic cleft. These results may contribute to a better understanding of the neuroprotective role of NGEN, emphasizing the influence of including this flavonoid in the diet for human health, possibly preventing brain injury associated with iron overload.

Pharmacological evaluation of nasal delivery of selegiline hydrochloride-loaded thiolated chitosan nanoparticles for the treatment of depression

The aim of the present study was to investigate the propensity of thiolated chitosan nanoparticles (TCNs) to enhance the nasal delivery of selegiline hydrochloride. TCNs were synthesized by the ionic gelation method. The particle size distribution (PDI), entrapment efficiency (EE), and zeta potential of modified chitosan (CS) nanoparticles were found to be 215 ± 34.71 nm, 70 ± 2.71%, and + 17.06 mV, respectively. The forced swim and the tail suspension tests were used to evaluate the anti-depressant activity, in which elevated immobility time was found to reduce on treatment. TCNs seem to be promising candidates for nose-to-brain delivery in the evaluation of antidepressant activity.

Interference of Phenylethanoid Glycosides from Cistanche tubulosa with the MTT Assay

The MTT assay, as a screening method, has been widely used to measure the viability and proliferation of cells. However, it should be noted that MTT assay may not accurately reflect the effect of Cistanche tubulosa ethanolic extract on EA.hy926 cells viability. To investigate and identity the components responsible for the contradictory observations of the MTT assay, echinacoside and acteoside, two main phenylethanoid glycosides, from C. tubulosa ethanolic extract were isolated. The data derived from CCK-8, Hoechst 33342 and annexin V-FITC/PI assays suggest that the caffeyl group present in both isolated compounds was responsible for the conflicting results of the MTT assay. These data emphasize the need of using a variety of different methods to determine the effect of medicinal agents on cell viability to avoid generating misleading results.

Comparative in vitro biological evaluation of daunorubicin containing GnRH-I and GnRH-II conjugates developed for tumor targeting

Hormone based drug targeting is a promising tool for selective tumor therapy. In this study, synthesis and systematic comparative biological evaluation of novel drug containing analogs of gonadotropin-releasing hormone GnRH-I and GnRH-II is reported demonstrating their suitability for tumor targeting. The cytotoxic conjugates were prepared by the attachment of the chemotherapeutical agent daunorubicin (Dau) to GnRH analogs directly or through an enzyme-labile spacer with oxime linkage. All conjugates were found to be proteolytically stable under circumstances applied in biological assays. Both GnRH-I and GnRH-II were able to bind similarly to high-affinity GnRH-I receptors on human pituitary and human prostate cancer cells. The in vitro long-term cytotoxic effect of the conjugates was comparable with that of the free drug in human breast and colon cancer cell lines. Furthermore, a concentration-dependent cellular uptake profile was observed. The in vitro apoptotic effect of the compounds was evaluated by flow cytometry analysis using annexin-V. Our results show that both the GnRH-I and the GnRH-II based analogs might be applied for targeted tumor therapy.

Anticancer and antiangiogenic activity of surfactant-free nanoparticles based on self-assembled polymeric derivatives of vitamin E: structure-activity relationship

α-Tocopheryl succinate (α-TOS) is a well-known mitochondrially targeted anticancer compound, however, it is highly hydrophobic and toxic. In order to improve its activity and reduce its toxicity, new surfactant-free biologically active nanoparticles (NP) were synthesized. A methacrylic derivative of α-TOS (MTOS) was prepared and incorporated in amphiphilic pseudoblock copolymers when copolymerized with N-vinylpyrrolidone (VP) by free radical polymerization (poly(VP-co-MTOS)). The selected poly(VP-co-MTOS) copolymers formed surfactant-free NP by nanoprecipitation with sizes between 96 and 220 nm and narrow size distribution, and the in vitro biological activity was tested. In order to understand the structure-activity relationship three other methacrylic monomers were synthesized and characterized: MVE did not have the succinate group, SPHY did not have the chromanol ring, and MPHY did not have both the succinate group and the chromanol ring. The corresponding families of copolymers (poly(VP-co-MVE), poly(VP-co-SPHY), and poly(VP-co-MPHY)) were synthesized and characterized, and their biological activity was compared to poly(VP-co-MTOS). Both poly(VP-co-MTOS) and poly(VP-co-MVE) presented triple action: reduced cell viability of cancer cells with little or no harm to normal cells (anticancer), reduced viability of proliferating endothelial cells with little or no harm to quiescent endothelial cells (antiangiogenic), and efficiently encapsulated hydrophobic molecules (nanocarrier). The anticancer and antiangiogenic activity of the synthesized copolymers is demonstrated as the active compound (vitamin E or α-tocopheryl succinate) do not need to be cleaved to trigger the biological action targeting ubiquinone binding sites of complex II. Poly(VP-co-SPHY) and poly(VP-co-MPHY) also formed surfactant-free NP that were also endocyted by the assayed cells; however, these NP did not selectively reduce cell viability of cancer cells. Therefore, the chromanol ring of the vitamin E analogues has an important role in the biological activity of the copolymers. Moreover, when succinate moiety is substituted and vitamin E is directly linked to the macromolecular chain through an ester bond, the biological activity is maintained.

New photostable naphthalimide-based fluorescent probe for mitochondrial imaging and tracking

Monitoring mitochondria morphological changes temporally and spatially exhibits significant importance for diagnosing, preventing and treating various diseases related to mitochondrial dysfunction. However, the application of commercially available mitochondria trackers is limited due to their poor photostability. To overcome these disadvantages, we designed and synthesized a mitochondria-localized fluorescent probe by conjugating 1,8-naphthalimide with triphenylphosphonium (i.e. NPA-TPP). The structure and characteristic of NPA-TPP was characterized by UV-vis, fluorescence spectroscopy, (1)HNMR, (13)CNMR, FTIR, MS, etc. The photostability and cell imaging were performed on the laser scanning confocal microscopy. Moreover, the cytotoxicity of NPA-TPP on cells was evaluated using (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay. The results showed that NPA-TPP not only has high sensitivity and specificity to mitochondria, but also exhibits super-high photostability, negligible cytotoxicity and good water solubility. In short, NPA-TPP indicates great potential for targeting mitochondria and enables a real-time and long-term tracking mitochondrial dynamics changes.

Viability and proliferation of L929, tumour and hybridoma cells in the culture media containing sericin protein as a supplement or serum substitute

Cell cultures often require the addition of animal serum and other supplements. In this study, silk sericin, a bioactive protein, recovered from the waste of silk floss production was hydrolysed into three pepsin-degraded sericin peptides with different ranges of molecular mass. Normal animal cells, tumour cells and hybridoma cells were cultured systematically in FBS culture media containing sericin as a supplement or serum substitute. The culture test and microscopic observation of L929 cells showed that the smaller molecular weight of the degraded sericin is most suitable for cell culture. The cell culture results showed that with the degradation of sericin, for normal mouse fibroblast L929 cells, addition of 0.75 % sericin into FBS culture medium yields cell viability that is superior to FBS culture medium alone. When all serum was replaced by sericin, cell viability in the sericin medium could reach about one half of that in FBS medium. When in a medium containing a mixture of FBS: sericin (6:4, v/v), the cell culture effect is about 80 %. For the cultures of four tumour and one hybridoma cells, regardless of the molecular weight range, these degraded sericin peptides could substitute all serum in FBS media. The cell viability and proliferation of these tumour and hybridoma cells are equivalent or superior to that in FBS medium. In other words, cell viability and proliferation of these tumour and hybridoma cells in sericin media are more preferable to serum media. The mechanism of the sericin protein to promote cell growth and proliferation will be further investigated later.

Protective effects of N-acetylcysteine against hyperoxaluria induced mitochondrial dysfunction in male wistar rats

The purpose of the present study was to evaluate the nephro-protective potential of N-acetylcysteine against hyperoxaluria-induced renal mitochondrial dysfunction in rats. Nine days dosing of 0.4 % ethylene glycol +1 % ammonium chloride, developed hyperoxaluria in male wistar rats which resulted in renal injury and dysfunction as supported by increased level of urinary lactate dehydrogenase, calcium, and decreased creatinine clearance. Mitochondrial oxidative strain in hyperoxaluric animals was evident by decreased levels of superoxide dismutase, glutathione peroxidase, glutathione reductase, reduced glutathione, and an increased lipid peroxidation. Declined activities of respiratory chain enzymes and tricarboxylic acid cycle enzymes showed mitochondrial dysfunction in hyperoxaluric animals. N-acetylcysteine (50 mg/kg, i.p.), by virtue of its -SH reviving power, was able to increase the glutathione levels and thus decrease the oxidative stress in renal mitochondria. Hence, mitochondrial damage is, evidently, an essential event in ethylene glycol-induced hyperoxaluria and N-acetylcysteine presented itself as a safe and effective remedy in combating nephrolithiasis.

Acute nitrogen dioxide inhalation induces mitochondrial dysfunction in rat brain

Recent epidemiological literatures imply that NO2 is a potential risk factor of neurological disorders. Whereas, the pathogenesis of various neurological diseases has been confirmed correlate to mitochondrial dysfunction, and mitochondria play the crucial roles in energy metabolism, free radicals production and apoptosis triggering in response to neuronal injury. Therefore, to clarify the possible mechanisms for NO2-induced neurotoxicity, in the present study, we investigated the possible effects of acute NO2 inhalation (5, 10 and 20mg/m(3) with 5h/day for 7 days) on energy metabolism and biogenesis in rat cortex, mainly including mitochondrial ultrastructure, mitochondrial membrane potential, cytochrome c oxidase activity, cytochrome c oxidase (CO) and ATP synthase subunits, ATP content, and transcription factors. The results showed that NO2 exposure induced mitochondrial morphological changes in rat cortex, and the alteration was coupled with the abnormality of mitochondrial energy metabolism, including decreased respiratory complexes, reduced ATP production and increased production of ROS. Also, increased ROS in turn caused mitochondrial membrane damage, energy production defect and mitochondrial biogenesis inhibition. It suggests the significantly damaged mitochondrial energy metabolism and impaired biogenesis in rat brain after NO2 exposure, and provides a new understanding of the pathophysiological mechanisms of NO2-induced neurological disorders.

Effects of temozolomide (TMZ) on the expression and interaction of heat shock proteins (HSPs) and DNA repair proteins in human malignant glioma cells

We previously reported the association of HSPA1A and HSPB1 with high-grade astrocytomas, suggesting that these proteins might be involved in disease outcome and response to treatment. With the aim to better understand the resistance/susceptibility processes associated to temozolomide (TMZ) treatment, the current study was performed in three human malignant glioma cell lines by focusing on several levels: (a) apoptotic index and senescence, (b) DNA damage, and (c) interaction of HSPB1 with players of the DNA damage response. Three human glioma cell lines, Gli36, U87, and DBTRG, were treated with TMZ evaluating cell viability and survival, apoptosis, senescence, and comets (comet assay). The expression of HSPA (HSPA1A and HSPA8), HSPB1, O6-methylguanine-DNA methyltransferase (MGMT), MLH1, and MSH2 was determined by immunocytochemistry, immunofluorescence, and Western blot. Immunoprecipitation was used to analyze protein interaction. The cell lines exhibited differences in viability, apoptosis, and senescence after TMZ administration. We then focused on Gli36 cells (relatively unstudied) which showed very low recovery capacity following TMZ treatment, and this was related to high DNA damage levels; however, the cells maintained their viability. In these cells, MGMT, MSH2, HSPA, and HSPB1 levels increased significantly after TMZ administration. In addition, MSH2 and HSPB1 proteins appeared co-localized by confocal microscopy. This co-localization increased after TMZ treatment, and in immunoprecipitation analysis, MSH2 and HSPB1 appeared interacting. In contrast, HSPB1 did not interact with MGMT. We show in glioma cells the biological effects of TMZ and how this drug affects the expression levels of heat shock proteins (HSPs), MGMT, MSH2, and MLH1. In Gli36 cells, the results suggest that interactions between HSPB1 and MSH2, including co-nuclear localization, may be important in determining cell sensitivity to TMZ.

Activation of the AGE/RAGE system in the brains of rats and in SH-SY5Y cells exposed to high level of fluoride might connect to oxidative stress

To explore the mechanisms by which chronic fluorosis damages the brain, we determined the levels of the advanced glycation end-products (AGEs), the receptor for AGE (RAGE), NADPH oxidase-2 (NOX2), reactive oxygen species (ROS) and malondialdehyde (MDA) in the brains of rats and/or SH-SY5Y cells exposed to different levels of sodium fluoride (5 or 50 ppm in the drinking water for 3 or 6 months and in the incubation medium for as long as 48 h, respectively). The levels of AGEs, RAGE and NOX2 protein and mRNA were measured by an Elisa assay, Western blotting and real-time PCR, respectively. The ROS content was assessed by fluorescein staining and MDA by thiobarbituric acid-reactive substance assay. In comparison to the unexposed controls, the protein and mRNA levels of AGEs, RAGE and NOX2 in the brains of rats after 6 months of exposure and in SH-SY5Y cells following high-dose exposure to fluoride were elevated. In contrast, no significant changes in these parameters were detected in the rats exposed for 3 months. In addition, the levels of ROS and MDA in the SH-SY5Y cells exposed to high-dose of fluoride were elevated in a manner that correlated positively with the levels of AGE/RAGE. In conclusion, our present results indicate that excessive fluoride can activate the AGE/RAGE pathway, which might in turn enhance oxidative stress.

Synthesis, characterization and applications of selenocysteine-responsive nanoprobe based on dinitrobenzene sulfonyl-modified poly(carbonate) micelles

Dinitrobenzenesulfonyl-modified micelles can be used for selenocysteine detection in cells and tissues.

Adsorption and separation of amyloid beta aggregates using ferromagnetic nanoparticles coated with charged polymer brushes

Adsorption and separation of toxic Aβ aggregates (fibrils and oligomers) using ferromagnetic nanoparticles functionalized with a cationic polymer (C/Co@polyMAPTAC) was demonstrated.

Design, characterization and cellular uptake studies of fluorescence-labeled prototypic cathepsin inhibitors

Cysteine cathepsin inhibition and cellular uptake of a coumarin 343-containing dipeptide nitrile was analyzed.

Synthesis of dimethyl carbonate (DMC) based biodegradable nitrogen mustard ionic carbonate (NMIC) nanoparticles

Nitrogen mustard ionic carbonate with stable carbonate moiety was synthesized and cross-linked with the biopolymer chitosan. Subsequently, nanoparticles of cross linked chitosan were prepared for wound healing application.

In vitro oxygen-glucose deprivation to study ischemic cell death

Oxygen-glucose deprivation (OGD ) is widely used as an in vitro model for stroke, showing similarities with the in vivo models of brain ischemia. In order to perform OGD, cell or tissue cultures, such as primary neurons or organotypic slices, and acutely prepared tissue slices are usually incubated in a glucose-free medium under a deoxygenated atmosphere, for example in a hypoxic chamber. Here, we describe the step-by-step procedure to expose cultures and acute slices to OGD, focusing on the most suitable methods for assessing cellular death and/or viability. OGD is a simple yet highly useful technique, not only for the elucidation of the role of key cellular and molecular mechanisms underlying brain ischemia, but also for the development of novel neuroprotective strategies.

β2-microglobulin amyloid fibrils are nanoparticles that disrupt lysosomal membrane protein trafficking and inhibit protein degradation by lysosomes

Fragmentation of amyloid fibrils produces fibrils that are reduced in length but have an otherwise unchanged molecular architecture. The resultant nanoscale fibril particles inhibit the cellular reduction of the tetrazolium dye 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), a substrate commonly used to measure cell viability, to a greater extent than unfragmented fibrils. Here we show that the internalization of β2-microglobulin (β2m) amyloid fibrils is dependent on fibril length, with fragmented fibrils being more efficiently internalized by cells. Correspondingly, inhibiting the internalization of fragmented β2m fibrils rescued cellular MTT reduction. Incubation of cells with fragmented β2m fibrils did not, however, cause cell death. Instead, fragmented β2m fibrils accumulate in lysosomes, alter the trafficking of lysosomal membrane proteins, and inhibit the degradation of a model protein substrate by lysosomes. These findings suggest that nanoscale fibrils formed early during amyloid assembly reactions or by the fragmentation of longer fibrils could play a role in amyloid disease by disrupting protein degradation by lysosomes and trafficking in the endolysosomal pathway.

Liposomes and MTT cell viability assay: an incompatible affair

The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay is commonly used to evaluate the cytotoxicity potential of drugs vehicled by liposomes. However, liposome delivering drugs could produce inconsistent values of MTT absorbance. On the basis of previous experiments demonstrating the MTT affinity for lipid droplets, this paper aims to show that empty-liposomes interfere, per se, on MTT assay due to its lipidic nature. This brings into question the use of MTT testing cytotoxicity when liposomes are involved in delivering drugs.

Establishment of a three-dimensional culture system of gastric stem cells supporting mucous cell differentiation using microfibrous polycaprolactone scaffolds

OBJECTIVES

To generate various polycaprolactone (PCL) scaffolds and test their suitability for growth and differentiation of immortalized mouse gastric stem (mGS) cells.

MATERIALS AND METHODS

Non-porous, microporous and three-dimensional electrospun microfibrous PCL scaffolds were prepared and characterized for culture of mGS cells. First, growth of mGS cells was compared on these different scaffolds after 3 days culture, using viability assay and microscopy. Secondly, growth pattern of the cells on microfibrous scaffolds was studied after 3, 6, 9 and 12 days culture using DNA PicoGreen assay and scanning electron microscopy. Thirdly, differentiation of the cells grown on microfibrous scaffolds for 3 and 9 days was analysed using lectin/immunohistochemistry.

RESULTS

The mGS cells grew preferentially on microfibrous scaffolds. From 3 to 6 days, there was increase in cell number, followed by reduction by days 9 and 12. To test whether the reduction in cell number was associated with cell differentiation, cryosections of cell-containing scaffolds cultured for 3 and 9 days were probed with gastric epithelial cell differentiation markers. On day 3, none of the markers examined bound to the cells. However by day 9, approximately, 50% of them bound to N-acetyl-d-glucosamine-specific lectin and anti-trefoil factor 2 antibodies, indicating their differentiation into glandular mucus-secreting cells.

CONCLUSIONS

Microfibrous PCL scaffolds supported growth and differentiation of mGS cells into mucus-secreting cells. These data will help lay groundwork for future experiments to explore use of gastric stem cells and PCL scaffolds in stomach tissue engineering.

Hesperidin alleviates cognitive impairment, mitochondrial dysfunction and oxidative stress in a mouse model of Alzheimer's disease

The role of mitochondrial dysfunction and oxidative stress has been well-documented in Alzheimer's disease (AD). Bioflavonoids are being utilised as neuroprotectants in the treatment of various neurological disorders, including AD. Therefore, we conducted this current study in order to explore the effects of hesperidin (a flavanone glycoside) against amyloid-β (Aβ)-induced cognitive dysfunction, oxidative damage and mitochondrial dysfunction in mice. Three-month-old APPswe/PS1dE9 transgenic mice were randomly assigned to a vehicle group, two hesperidin (either 50 or 100 mg/kg per day) groups, or an Aricept (2.5 mg/kg per day) group. After 16 weeks of treatment, although there was no obvious change in Aβ deposition in the hesperidin-treated (100 mg/kg per day) group, however, we found that the administration of hesperidin (100 mg/kg per day) resulted in the reduction of learning and memory deficits, improved locomotor activity, and the increase of anti-oxidative defense and mitochondrial complex I-IV enzymes activities. Furthermore, Glycogen synthase kinase-3β (GSK-3β) phosphorylation significantly increased in the hesperidin-treated (100 mg/kg per day) group. Taken together, these findings suggest that a reduction in mitochondrial dysfunction through the inhibition of GSK-3β activity, coupled with an increase in anti-oxidative defense, may be one of the mechanisms by which hesperidin improves cognitive function in the APPswe/PS1dE9 transgenic mouse model of AD.

Porous NiTi shape memory alloys produced by SHS: microstructure and biocompatibility in comparison with Ti2Ni and TiNi3

Shape memory alloys based on NiTi have found their main applications in manufacturing of new biomedical devices mainly in surgery tools, stents and orthopedics. Porous NiTi can exhibit an engineering elastic modulus comparable to that of cortical bone (12-17 GPa). This condition, combined with proper pore size, allows good osteointegration. Open cells porous NiTi was produced by self propagating high temperature synthesis (SHS), starting from Ni and Ti mixed powders. The main NiTi phase is formed during SHS together with other Ni-Ti compounds. The biocompatibility of such material was investigated by single culture experiment and ionic release on small specimen. In particular, NiTi and porous NiTi were evaluated together with elemental Ti and Ni reference metals and the two intermetallic TiNi3, Ti2Ni phases. This approach permitted to clearly identify the influence of secondary phases in porous NiTi materials and relation with Ni-ion release. The results indicated, apart the well-known high toxicity of Ni, also toxicity of TiNi3, whilst phases with higher Ti content showed high biocompatibility. A slightly reduced biocompatibility of porous NiTi was ascribed to combined effect of TiNi3 presence and topography that requires higher effort for the cells to adapt to the surface.

Synthesis of poly(ester-carbonate) with a pendant acetylcholine analog for promoting neurite growth

The modification of biodegradable polyesters with bioactive molecules has become an important strategy for controlling neuron adhesion and neurite outgrowth in nerve regeneration. In this study we report a biodegradable poly(ester-carbonate) with a pendant acetylcholine analog, which a neurotransmitter for the enhancement of neuron adhesion and outgrowth. The acetylcholine-functionalized poly(ester-carbonate) (Ach-P(LA-ClTMC)) was prepared by copolymerizing l-lactide (LA) and 5-methyl-5-chloroethoxycarbonyl trimethylene carbonate (ClTMC), followed by quaternization with trimethylamine. The acetylcholine analog content could be modulated by changing the molar feeding fraction of ClTMC. The incorporation of the acetylcholine analog improved the hydrophilicity of the films, but the acetylcholine analog content did not significantly influence the surface morphology of the acetylcholine-functionalized films. The results of PC12 cell culture showed that the acetylcholine analog promoted cell viability and neurite outgrowth in a concentration-dependent manner. The longest length of neurite and the percentage of cells bearing neurites were obtained on the Ach-P(LA-ClTMC)-10 film. All the results indicate that the integration of the acetylcholine analog at an appropriate fraction could be an effective strategy for optimizing the existing biodegradable polyesters for nerve regeneration applications.

Delineating the anti-cytotoxic and anti-genotoxic potentials of catechin hydrate against cadmium toxicity in human peripheral blood lymphocytes

Catechins (flavan-3-ol) are a type of natural phenol and well-studied antioxidants. Catechin hydrate, also known as taxifolin; is non-mutagenic, low in toxicity compared to other immunomodulator antioxidants. We aimed to determine the potential of catechin hydrate to prevent the cyto-genotoxic effects of cadmium in lymphocytes; demonstrate the immuno-protective activity of catechin hydrate. Our previous study indicated that cadmium is apoptogenic. Lymphocytes were treated with catechin hydrate or cadmium and catechine hydrate combinations (range 0.1-100μM) to determine their effects on cell viability. Lymphocytes treated with 100μM catechin hydrate and 100μM cadmium showed cell viability 70.65±6.92% and 5.69±2.27%, respectively. In our previous study cadmium (10 and 20μM) induced apoptosis in 31.8% and 44.4% of lymphocytes, respectively. However, the percentage of apoptotic cells after treatment with the combination of cadmium and catechin hydrate was not significantly different from that of catechin hydrate (P>0.05). Only 7.3% and 10.5% of the lymphocytes were apoptotic after treatment with 10μM cadmium+10μM catechin hydrate and 20μM cadmium+20μM catechin hydrate, respectively. The anti-geno-cytotoxic and immuno-protective potential of catechin hydrate was also demonstrated by the non-significant expression of apoptosis-related genes after treatment with catechin hydrate.

Improvement of mitochondrial NAD(+)/FAD(+)-linked state-3 respiration by caffeine attenuates quinolinic acid induced motor impairment in rats: implications in Huntington's disease

BACKGROUND

Chronic quinolinic acid (QA) lesions in rats closely resemble Huntington's disease like conditions. Oxidative stress and mitochondrial dysfunction have long been implicated in the neurotoxic effects of QA acting through N-methyl-d-aspartate (NMDA) receptors. Reports suggest that inhibition of adenosine A2A receptor function elicits neuroprotective effect in QA induced neurotoxicity in rats. Caffeine, a preferential A2A receptor antagonist imitates antioxidant like actions and exerts neuroprotective effects in various neurodegenerative conditions. Thus, the present study was designed to evaluate the neuroprotective effects of caffeine against QA induced neurotoxicity in rats.

METHODS

In the present study, QA (200nmol/2μl saline) has been administered bilaterally to the striatum of rats followed by chronic caffeine (10, 20 and 40mg/kg) administration for 21 days. Motor performance of the animals was evaluated in weekly intervals and subsequently after 21 days, the animals were sacrificed and measurement of mitochondrial complexes activity, respiration rate and endogenous antioxidant levels were carried out in the striatal region.

RESULTS

Single intrastriatal QA administration resulted in drastic reduction in body weight, marked motor impairment (decreased total locomotor activity in actophotometer and impaired grip strength in rotarod), increased oxidative stress, impaired mitochondrial complexes activities and decreased state 3 respiration (NAD(+)/FAD(+)-linked) in rats. However, chronic treatment of caffeine for 21 days significantly attenuated the QA induced behavioural, biochemical and mitochondrial alterations displaying neuroprotective efficacy.

CONCLUSION

The study highlights the possible involvement of A2A receptor antagonism in the neuroprotective effect of caffeine against QA induced mitochondrial dysfunction and oxidative stress in rats.