Low dose (-)deprenyl is cytoprotective: it maintains mitochondrial membrane potential and eliminates oxygen radicals

Selegiline (L-Deprenyl) Mitigated Oxidative Stress, Cognitive Abnormalities, and Histopathological Change in Rats: Alternative Therapy in Transient Global Ischemia

Selegiline (L-deprenyl) is the major drug which is used in the treatment of Parkinson's disease because of its neurotrophic and antiapoptotic properties. Previous studies suggested that low dose of L-methamphetamine (L-METH) caused lower mortality rate in patients with severe traumatic brain injury. As L-methamphetamine is one of the metabolites of selegiline, the present study aims to examine whether L-deprenyl can improve cognitive, biochemical, and histopathological injury in animal model of transient global ischemia. The animals were randomized in ten groups orally gavaged three times a week for 28 days. Then, novel object recognition (NOR) was conducted to assess their behavioral abnormality. After scarification of the rats, their brains were divided into two sections to measure oxidative stress parameters and perform pathological evaluations in rats. Our data revealed the involvement of oxidative stress, behavioral despair, and pathological data in transient global ischemia rats. Significant recovery in cognitive behavior, oxidative stress biomarker, and number of dead cell in histopathological assay was observed in rats treated with 1,2 and 4 mg/kg of selegiline. So, selegiline appears to be useful in alternative therapy of transient global ischemia.

Psychiatric drugs impact mitochondrial function in brain and other tissues

Mitochondria have been linked to the etiology of schizophrenia (SZ). However, studies of mitochondria in SZ might be confounded by the effects of pharmacological treatment with antipsychotic drugs (APDs) and other common medications. This review summarizes findings on relevant mitochondria mechanisms underlying SZ, and the potential impact of psychoactive drugs including primarily APDs, but also antidepressants and anxiolytics. The summarized data suggest that APDs impair mitochondria function by decreasing Complex I activity and ATP production and dissipation of the mitochondria membrane potential. At the same time, in the brains of patients with SZ, antipsychotic drug treatment normalizes gene expression modules enriched in mitochondrial genes that are decreased in SZ. This indicates that APDs may have both positive and negative effects on mitochondria. The available evidence suggests three conclusions i) alterations in mitochondria functions in SZ exist prior to APD treatment, ii) mitochondria alterations in SZ can be reversed by APD treatment, and iii) APDs directly cause impairment of mitochondria function. Overall, the mechanisms of action of psychiatric drugs on mitochondria are both direct and indirect; we conclude the effects of APDs on mitochondria may contribute to both their therapeutic and metabolic side effects. These studies support the hypothesis that neuronal mitochondria are an etiological factor in SZ. Moreover, APDs and other drugs must be considered in the evaluation of this pathophysiological role of mitochondria in SZ. Considering these effects, pharmacological actions on mitochondria may be a worthwhile target for further APD development.

Green synthesis of labeled CeO2 nanoparticles with 99mTc and its biodistribution evaluation in mice

AIMS

The in vivo targeted diagnostic applications of biosynthetic Cerium oxide nanoparticles (CeO₂-NPs), prepared by applying chitosan as a stabilizer, was explored by evaluating the cytotoxicity through MTT assay on WEHI 164 cell line, the Hemolytic activity of CeO₂-NPs and biodistribution in rats.

MAIN METHODS

The CeO₂-NPs were characterized through the use of TGA/DTG, PXRD, FESEM, FTIR, and UV-Vis spectroscopy. The biodistribution of CeO₂-NPs were determined by directly labeled nanoparticles with Technetium-99 m (99mTc) radioisotope (99mTc-CeO₂-NPs). The labeling efficiency and stability of 99mTc-CeO₂-NPs were also measured with Instant Thin Layer Chromatography (ITLC) method. The saturation study was investigated by 1 mCi of 99mTc-CeO₂-NPs using different concentrations of WEHI 164 cells after 4 h of incubation. In vivo biodistribution study was performed by intravenous injection of 600 μCi/200 μL 99mTc-CeO₂-NPs through rat's tail.

KEY FINDINGS

CeO₂-NPs seemed to have a low cytotoxic effect on WEHI 164 cell line and did not result in hemolysis. The biodistribution of CeO₂-NPs has shown that a huge amount of 99mTc-CeO₂-NPs was amassed in the living human organs, including liver, lung, spleen, stomach, and thyroid which shows the in vivo stability of the labeled conjugate. Herein, we have developed a facile, economical, and greener synthetic procedure applying Chitosan template. This green approach is comparable to conventional methods that utilize hazardous materials which are would be a suitable alternative to circumvent synthetic issues related to these materials.

SIGNIFICANCE

The bio-applications of nano-sized CeO₂-NPs were explored to find new horizon to use nanotechnology as the diagnostic tool.

Cerebral ischemia/repefusion injury: From bench space to bedside

While stroke research represents the primary interface between circulation and brain research, the hemostasis system also carries a pivotal role in the mechanism of vascular brain injury. The complex interrelated events triggered by the energy crisis have a specific spatial and temporal pattern arching from the initial damage to the final events of brain repair. The complexity of the pathophysiology make it difficult to model this disease, therefore it is challenging to find appropriate therapeutic targets. The ever-persistent antagonism between the positive results of drug candidates in the experimental stroke models and the failures of the clinical trials prompts changes in the research strategy, especially in the field of potential neuroprotective therapies. System biology approach could initiate new directions in the future for both preclinical and clinical research. Incentive methods aimed at anti-apoptosis mechanisms and the augmentation of post-ischemic brain repair could benefit the facts, that these processes can be targeted much longer following the cell-necrosis in the hyper-acute phase. Sequential monitoring of candidate genes and proteins responsible for stroke progression and post-stroke repair seems to be useful both in therapeutic target-identification, and in clinical testing. Understanding the mechanism behind the effect of selegiline and other drugs capable of activating the anti-apoptotic gene expression could help to find new approaches to enhance the regenerative potential in the remodeling of neuronal and microvascular networks.

pH-sensitive micelles for the intracellular co-delivery of curcumin and Pluronic L61 unimers for synergistic reversal effect of multidrug resistance

Pluronic L61 unimers, which are biomacromolecular modulators, and curcumin, a small-molecule modulator, were co-formulated into pH-sensitive micelles to reveal the full synergistic potential of combination drug treatments to reverse multidrug resistance (MDR). Compared to monotherapy, combined therapy significantly improved the cytotoxicity, cellular uptake and apoptotic effects of doxorubicin (DOX) against MCF-7/ADR cells. In mechanistic studies, both L61 and curcumin enhanced the cytotoxic effect by acting on mitochondrial signalling pathways. The compounds selectively accumulated in the mitochondria and disabled the mitochondria by dissipating the mitochondrial membrane potential, decreasing the ATP levels, and releasing cytochrome c, which initiated a cascade of caspase-9 and caspase-3 reactions. Furthermore, both curcumin and L61 down-regulated the expression and function of P-gp in response to drug efflux from the MCF-7/ADR cells. In the MCF-7/ADR tumour-bearing mouse model, intravenous administration of the combined therapy directly targeted the tumour, as revealed by the accumulation of DiR in the tumour site, which led to a significant inhibition of tumour growth without measurable side effects. In conclusion, co-formulation consisting of L61 and curcumin in pH-sensitive micelles induced significant synergistic effects on the reversal of MDR. Therefore, the intracellular co-delivery of various MDR modulators has great potential to reverse MDR in tumours.

Biodegradable mixed MPEG-SS-2SA/TPGS micelles for triggered intracellular release of paclitaxel and reversing multidrug resistance

In this study, a type of multifunctional mixed micelles were prepared by a novel biodegradable amphiphilic polymer (MPEG-SS-2SA) and a multidrug resistance (MDR) reversal agent (d-α-tocopheryl polyethylene glycol succinate, TPGS). The mixed micelles could achieve rapid intracellular drug release and reversal of MDR. First, the amphiphilic polymer, MPEG-SS-2SA, was synthesized through disulfide bonds between poly (ethylene glycol) monomethyl ether (MPEG) and stearic acid (SA). The structure of the obtained polymer was similar to poly (ethylene glycol)-phosphatidylethanolamine (PEG-PE). Then the mixed micelles, MPEG-SS-2SA/TPGS, were prepared by MPEG-SS-2SA and TPGS through the thin film hydration method and loaded paclitaxel (PTX) as the model drug. The in vitro release study revealed that the mixed micelles could rapidly release PTX within 24 h under a reductive environment because of the breaking of disulfide bonds. In cell experiments, the mixed micelles significantly inhibited the activity of mitochondrial respiratory complex II, also reduced the mitochondrial membrane potential, and the content of adenosine triphosphate, thus effectively inhibiting the efflux of PTX from cells. Moreover, in the confocal laser scanning microscopy, cellular uptake and 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assays, the MPEG-SS-2SA/TPGS micelles achieved faster release and more uptake of PTX in Michigan Cancer Foundation-7/PTX cells and showed better antitumor effects as compared with the insensitive control. In conclusion, the biodegradable mixed micelles, MPEG-SS-2SA/TPGS, could be potential vehicles for delivering hydrophobic chemotherapeutic drugs in MDR cancer therapy.

Antitumor effects of the benzophenanthridine alkaloid sanguinarine: Evidence and perspectives

Historically, natural products have represented a significant source of anticancer agents, with plant-derived drugs becoming increasingly explored. In particular, sanguinarine is a benzophenanthridine alkaloid obtained from the root of Sanguinaria canadensis, and from other poppy Fumaria species, with recognized anti-microbial, anti-oxidant and anti-inflammatory properties. Recently, increasing evidence that sanguinarine exibits anticancer potential through its capability of inducing apoptosis and/or antiproliferative effects on tumor cells, has been proved. Moreover, its antitumor seems to be due not only to its pro-apoptotic and inhibitory effects on tumor growth, but also to its antiangiogenic and anti-invasive properties. Although the precise mechanisms underlying the antitumor activity of this compound remain not fully understood, in this review we will focus on the most recent findings about the cellular and molecular pathways affected by sanguinarine, together with the rationale of its potential application in clinic. The complex of data currently available suggest the potential application of sanguinarine as an adjuvant in the therapy of cancer, but further pre-clinical studies are needed before such an antitumor strategy can be effectively translated in the clinical practice.

An explorative study regarding the effect of l-deprenyl on cognitive and functional recovery in patients after stroke

INTRODUCTION

Selegiline (l-deprenyl) is a selective monoamine oxidase type B inhibitor that has been shown to have neurotrophic and anti-apoptotic properties and to protect neurons in different experimental models of cerebral ischaemia. The aim of this explorative study was to investigate whether selegiline could enhance cognitive and functional recovery in stroke survivors.

METHODS

This was a randomized controlled study in which patients enrolled within two weeks of stroke underwent a clinical and functional evaluation and a neuropsychological assessment. The patients were given selegiline (10mg/day) or matched placebo once a day for six weeks in addition to standard rehabilitation care.

RESULTS

Of 137 stroke survivors, 47 patients met the inclusion criteria and were randomly assigned to the Study Group (n=23) or the Control Group (n=24). The statistical analysis showed a significant improvement in most neuropsychological tests after two and six weeks in the study group; these improvements were not replicated in the control group. The between-group analysis revealed that the domains of attention and executive functions benefited most from the drug treatment. With regard to functional status, comparison of clinical scores at admission and discharge showed a statistically significant enhancement in both groups without statistically significant differences between the groups.

CONCLUSIONS

These preliminary results suggest that selegiline administered in the subacute phase can promote cognitive functioning in stroke patients. Further studies will elucidate whether and how this enhancement can impact on functional recovery in the short and in the long term.

Reversing multidrug resistance by intracellular delivery of Pluronic® P85 unimers

Pluronics have been demonstrated as excellent multidrug resistance (MDR) reversal agent in the form of unimers rather than micelles. However, the effective intracellular delivery of Pluronic(®) unimers to MDR cancer cells still remains a big challenge. To address this issue, a mixed micellar system based mainly on the pH-sensitive copolymer of poly (L-histidine)-poly (D,L-lactide)-polyethyleneglycol-poly (D,L-lactide)-poly (L-histidine) (PHis-PLA-PEG-PLA-PHis) and Pluronic(®) F127, some of which was conjugated with folate, was constructed to intracellularly deliver the unimers of Pluronic(®) P85 to MDR cells. The folate-mediated endosomal pH-sensitive mixed micelles (pHendoSM-P85/f) were prepared by a thin-film hydration method, by which Pluronic(®) P85 unimers and doxorubicin (DOX) were incoporated into the mixed micelles. The incorporation of Pluronic(®) P85 unimers was investigated by the surface tension test. The results indicated that the Pluronic(®) P85 unimers probably first inserted into the binary mixed micelles and then formed a triple-component mixed micelles with Pluronic(®) F127 and PHis-PLA-PEG-PLA-PHis as the loading content increased. Further analyzed with flow cytometry, confocal laser scanning microscopy (CLSM) and MTT assay, the micelles with inserted Pluronic(®) P85 unimers demonstrated much more cellular uptake and higher cytotoxicity against MDR cells than the triple-component mixed micelles and plain Pluronic(®) micelles. The enhanced MDR reversal effect was attributed to the successful intracellular delivery of Pluronic(®) P85 unimers to the MDR cells, which was confirmed by the subcellular colocalization of Pluronic(®) P85 unimers with mitochondria, the decreased ATP energy and mitochondrial membrane potential (MP) in the MCF-7/ADR cells. The pHendoSM-P85/f/DOX also demonstrated more dramatic antitumor efficiency and remarkable reduction of ATP energy in the MDR cells in tumors than the control formulations. The intracellular delivery of Pluronic(®) P85 unimers to the MDR cells based on the targeted and endosomal pH triggerd release mixed micelles has been demonstrated as a promising approach to reverse MDR.

Sanguinarine induces apoptosis in human colorectal cancer HCT-116 cells through ROS-mediated Egr-1 activation and mitochondrial dysfunction

We examined the effects of sanguinarine, a benzophenanthridine alkaloid, on reactive oxygen species (ROS) production and the association of these effects with apoptotic cell death in a human colorectal cancer HCT-116 cell line. Sanguinarine generated ROS, which was followed by a decrease in the mitochondrial membrane potential (MMP), the activation of caspase-9 and -3, and the down-regulation of anti-apoptotic proteins, such as Bcl2, XIAP and cIAP-1. Sanguinarine also promoted the activation of caspase-8 and truncation of Bid (tBid). However, the quenching of ROS generation by N-acetyl-l-cysteine, a scavenger of ROS, reversed the sanguinarine-induced apoptosis effects via inhibition of the MMP collapse, tBid expression, and activation of caspases. Sanguinarine also markedly induced the expression of the early growth response gene-1 (Egr-1) during the early period, after which expression level was decreased. In addition, HCT-116 cells transfected with Egr-1 siRNA displayed significant blockage of sanguinarine-induced apoptotic activity in a ROS-dependent manner. These observations clearly indicate that ROS, which are key mediators of Egr-1 activation and MMP collapse, are involved in the early molecular events in the sanguinarine-induced apoptotic pathway acting in HCT-116 cells.

Poly(caprolactone)-modified Pluronic P105 micelles for reversal of paclitaxcel-resistance in SKOV-3 tumors

Three poly(caprolactone)-modified Pluronic P105 polymers (P105/PCLs) were synthesized using commercially available ε-caprolactone monomers and Pluronic P105 copolymers. The chemical structures, compositions and molecular weights of the P105/PCLs were confirmed by FT-IR, (1)H NMR and GPC measurements. Three paclitaxel (PTX)-loaded P105/PCL polymeric micelles were then prepared, and they showed average diameters in the range of 30-150 nm, drug-loading coefficients of 0.15%-5.43%, and encapsulation ratios of 2.1%-76.53%. The in vitro cytotoxicity assay demonstrated that three PTX-loaded P105/PCL micelles were able to sensitize the resistant SKOV-3/PTX tumor cells. The PTX-loaded P105/PCL(50) micelle was then selected for an in vivo antitumor efficacy study. The tumor volumes in nude mice bearing s.c. resistant SKOV-3/PTX carcinoma treated with this micellar PTX were significantly less than the control group treated with Taxol. It was demonstrated that three PCL-modified P105 monomers and micelles inhibited P-gP efflux activity in the resistant SKOV-3/PTX cells via at least three intracellular events: 1) inhibition of ATPase of P-gP, 2) decrease of membrane microviscosity and 3) a loss of mitochondrial membrane potential and subsequent decrease of ATP levels at the concentration of monomers (0.001%) and/or micelles (0.01-1.0%). Considering other favorable characteristics, such as sustained PTX release in vitro, long-circulating time in vivo and increased PTX concentration in the tissues of ovaries and uterus in mice, the PCL-modified Pluronic P105 polymeric micelle system could have important clinical implications for delivery of paclitaxel and treatment of the resistant ovarian tumors.

Deprenyl prevents MPP(+)-induced oxidative damage in PC12 cells by the upregulation of Nrf2-mediated NQO1 expression through the activation of PI3K/Akt and Erk

Neuroprotection has been the focus of several current efforts to develop a strategy for the treatment of Parkinson's disease (PD). The B-type monoamine oxidase (MAO-B) inhibitor deprenyl (selegiline) is used clinically as a PD therapeutic agent, however, its cytoprotective mechanism has not yet been fully elucidated. In this study, we show that deprenyl upregulates the expression and activity of NAD(P)H: quinone oxidoreductase 1 (NQO1), attenuates the increase in the quinoprotein levels in 1-methyl-4-phenylpyridinium (MPP(+))-treated PC12 cells, and protects PC12 cells from oxidative damage. Deprenyl triggers the nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) pathway by increasing the nuclear translocation and DNA-binding activity of Nrf2. Both the antioxidant activity of deprenyl and its effect on NQO1 upregulation were greatly attenuated in Nrf2 siRNA transfected cells. The phosphorylation of extracellular regulating protein kinase (Erk) and Akt can be induced by the administration of 50μM deprenyl in PC12 cells, and the ability of deprenyl to enhance NQO1 expression and Nrf2 nuclear translocation is partly attenuated by the mitogen-activated protein kinase kinase (MEK) inhibitor PD98059 and is almost completely attenuated by the phosphatidyl-inositol 3 kinase (PI3K) inhibitor LY294002. The activation of Nrf2/ARE signaling by deprenyl in PC12 cells is independent of MAO-B inhibition. Altogether, our findings indicate that deprenyl protects PC12 cells exposed to MPP(+) resulting from oxidative stress via the Nrf2-mediated upregulation of NQO1 involving both the PI3K/Akt and Erk pathways.

Elevated [11C]-D-deprenyl uptake in chronic Whiplash Associated Disorder suggests persistent musculoskeletal inflammation

There are few diagnostic tools for chronic musculoskeletal pain as structural imaging methods seldom reveal pathological alterations. This is especially true for Whiplash Associated Disorder, for which physical signs of persistent injuries to the neck have yet to be established. Here, we sought to visualize inflammatory processes in the neck region by means Positron Emission Tomography using the tracer ¹¹C-D-deprenyl, a potential marker for inflammation. Twenty-two patients with enduring pain after a rear impact car accident (Whiplash Associated Disorder grade II) and 14 healthy controls were investigated. Patients displayed significantly elevated tracer uptake in the neck, particularly in regions around the spineous process of the second cervical vertebra. This suggests that whiplash patients have signs of local persistent peripheral tissue inflammation, which may potentially serve as a diagnostic biomarker. The present investigation demonstrates that painful processes in the periphery can be objectively visualized and quantified with PET and that ¹¹C-D-deprenyl is a promising tracer for these purposes.

(-)Deprenyl-N-oxide, a (-)deprenyl metabolite, is cytoprotective after hypoxic injury in PC12 cells, or after transient brain ischemia in gerbils

BACKGROUND AND AIMS

(-)-Deprenyl (selegiline) possesses cyto-protective effect in a much lower concentration, than it is needed to inhibit MAO-B activity. In permanent MCA occlusion stroke model in rats, the infarct volume and the number of apoptotic neurons in the penumbra region were decreased by low concentration (-)deprenyl treatment. Augmented Bcl-2 protein expression was documented as the responsible factor of this effect. The stabilization of mitochondrial membrane and diminished ROS production are the further possible consequences of (-)deprenyl treatment. It is not clear however that (-)deprenyl, or its metabolites are the acting neuroprotective molecules in the hypoxic/ischemic conditions. We report here the possible cyto-protective effect of deprenyl-N-oxide (DNO), a recently synthesized (-)deprenyl metabolite.

METHODS

DNO in a very low dose (10(-5,-8,-12) M) was tested in PC12 cell culture after hypoxia and in gerbils after transient occlusion of bilateral common carotid artery. In PC12 culture the cell death was visualized by PI staining. The level of reactive oxygen species was measured by the Cerium method, and the mitochondrial membrane integrity was labeled by JC1 staining. Apoptotic neurons were counted on formaldehyde fixed gerbil brain slices after TUNEL and caspase-3 immune-staining - NIKON/BIORAD confocal microscopy was used for the quantitative analysis.

RESULTS

DNO treatment significantly decreased the frequency of cell death in PC12 cultures after hypoxia, increased the mitochondrial transmembrane potential (DeltaY(m)) and decreased the ROS production. In the CA2 regions of gerbil hippocampus, we found significantly less apoptotic neurons than in the untreated controls.

CONCLUSION

Transient hypoxia or ischemia induced cell damage could be diminished by DNO. This (-)deprenyl metabolite is an active cell protective molecule.

Bcl-2 or Bcl-XL gene therapy reduces apoptosis and increases plasticity protein GAP-43 in PC12 cells

The anti-apoptotic gene replacement could be an option in preventing hypoxia induced neuronal loss-necrosis and/or apoptosis. This intervention is however still controversial. In this paper, we tested the bcl-2 or bcl-XL anti-apoptotic gene transfers using an adenovirus vector in PC12 cells after hypoxia and re-oxygenation. Gene delivery results in a significant increase in both Bcl-2 and Bcl-XL proteins expression. Hypoxia (1h)/re-oxygenation (4-48 h) have a detrimental effect upon cultured cells by inducing increased apoptosis by 30% compared to the controls. After hypoxia the compromised mitochondrial membrane function was detected by decreased tetramethyl-rhodamine-ethylester (TMRE) staining. Anti-apoptotic genes transferred 1h after hypoxia, prevent the cell damage; the number of apoptotic cells has been reduced significantly and the gene transfers prevent mitochondrial membrane damage. Under normoxic conditions or following hypoxia the expression of plasticity protein, growth associated protein 43 (GAP-43) increased significantly by the gene treatment. We can conclude that anti-apoptotic gene transfers are not only cytoprotective as it is already documented before but these genes activate GAP-43 as well. This link on apoptotic signals and cell plasticity is a new finding.

CaIPF7817 is involved in the regulation of redox homeostasis in Candida albicans

CaIPF7817, a functionally unknown gene in Candida albicans, was suggested to be involved in the redox system previously, but its exact role is unknown. In this study, ipf7817 null mutant was generated with the URA-blaster method. After the deletion of CaIPF7817, intracellular levels of reactive oxygen species were significantly increased; mitochondrial membrane potential, a direct indicator of mitochondrial function, was elevated; some important redox-related genes, including GLR1, SOD2, and TRR1, were up-regulated; and the GSH/GSSG ratio was raised. These changes indicated that CaIPF7817 played important roles in the regulation of redox homeostasis in C. albicans.

Molecular mechanisms of euplotin C-induced apoptosis: involvement of mitochondrial dysfunction, oxidative stress and proteases

The metabolite euplotin C (EC), isolated from the marine ciliate Euplotes crassus, is a powerful cytotoxic and pro-apoptotic agent in tumour cell lines. For instance, EC induces the rapid depletion of ryanodine Ca(2+) stores, the release of cytochrome c from the mitochondria, and the activation of caspase-3, leading to apoptosis. The purpose of this study was to gain further insight into the mechanisms of EC-induced apoptosis in rat pheochromocytoma PC12 cells. We found that EC increases Bax/Bcl-2 ratio and that Bax is responsible of the EC-induced dissipation of the mitochondrial membrane potential (Deltapsi(m)). In addition, EC induces the generation of reactive oxygene species (ROS) without involvement of p53. The inhibition of ROS generation prevents, at least in part, the pro-apoptotic effects of EC as well as the effects of EC on Bax, Deltapsi(m) and intracellular free Ca(2+), indicating a cross-talk between different pathways. However, definition of the effector cascade turns out to be more complex than expected and caspase-independent mechanisms, acting in parallel with caspases, should also be considered. Among them, EC increases the expression/activity of calpains downstream of ROS generation, although calpains seem to exert protective effects.

Improvement of mouse brain mitochondrial function after deprenyl treatment

Deprenyl is a selective monoamine oxidase (MAO) B inhibitor, widely used for treatment of Parkinson's disease. The present study shows that deprenyl treatment was able to improve mitochondrial function. Fourteen month old mice were injected i.p. with deprenyl (20 mg/kg) and killed 1.5 h after the administration. Different brain subcellular fractions were isolated from control and deprenyl-treated animals to evaluate the effect of deprenyl on nitric oxide synthase (NOS) activity. Oxygen consumption, hydrogen peroxide (H(2)O(2)) production, mitochondrial membrane potential and calcium-induced permeability transition (MPT) were studied in intact mitochondria. In addition, the effect of deprenyl on respiratory complexes and MAO activities were evaluated in submitochondrial particles (SMP). Monoamine oxidase activity was found to be decreased by 55% in mitochondria from deprenyl-treated animals and as a consequence, H(2)O(2) production was significantly decreased. Deprenyl inhibited NOS activity in cytosolic fractions and SMP by 40% and 55%, respectively. In similar conditions, SMP from deprenyl-treated animals showed increased cytochrome oxidase activity. A 51% increase in the oxygen uptake in state 3 (active respiration state) was found after deprenyl treatment, but no significant changes were observed in state 4 (resting respiration state). Deprenyl treatment protected against calcium-induced depolarization and was able to inhibit calcium-induced MPT. This work provides evidence that deprenyl treatment exerts an improvement of brain mitochondrial function, through a reduction of free radical production, prevention of calcium-induced MPT and maintaining a mitochondrial transmembrane potential.

Visualization of mitochondrial membrane potential and reactive oxygen species via double staining

Quantitative and qualitative analysis of both generated reactive oxygen species (ROS) and mitochondrial membrane potential cannot be detected simultaneously. We here introduce a simple, new double staining method. We have successfully used this for several years utilizing cerium for ROS detection and JC-1 staining to assess the mitochondrial membrane potential. The resultant signals on laser confocal images can be localized in the same cells and can easily quantify them. We used a confocal microscope along with our new, combined staining method to both visualize mitochondrial membrane potential (DeltaPsim) and imaged ROS. These were quantified by JC-1 staining and by cerium ions with reflectance in a method modified in our laboratory. To test this double labeling technique we used PC 12 cells subjected to 1 h hypoxia and 24h re-oxygenization. We are able to produce a quantitative analysis of red/green signals of JC-1 that reflected the energy state of the cells. Cerium reflectance correlates with the amount of ROS release in the same cells. Significant differences have been calculated after hypoxia and re-oxygenation in both modality of the cell staining. The red/green ratio was 18.2+/-9.3 (n=30) in normoxic cells versus 1.65+/-0.9 (n=30) in the hypoxia/re-oxygenation group (p<0.05). In the same randomly selected cells the average cerium reflectance signal intensity was 2.5+/-1.2 (n=30) in the control group while 5.8+/-3.1 (n=30) in the hypoxia/re-oxygenation group (p<0.05). This assay, by characterizing hypoxic injury and re-oxygenization induced ROS production, offers a qualitative and quantitative method to detect the consequences of oxidative stress in experimental conditions and to detect different cell protective strategies.