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Abstract Background Extracts of Hypericum perforatum (St. John's wort) have been traditionally recommended for a wide range of medical conditions, in particular mild-to-moderate depression. The present study was designed to investigate the effect of Hypericum perforatum treatment in a mouse model of anxiety/depressive-like behavior, induced by chronic corticosterone administration. Methods CD1 mice were submitted to 7 weeks corticosterone administration and then behavioral tests as Open Field (OF), Novelty-Suppressed Feeding (NSF), Forced Swim Test (FST) were performed. Cell proliferation in hippocampal dentate gyrus (DG) was investigated by both 5-bromo-2'-deoxyuridine (BrdU) and doublecortin (DCX) immunohistochemistry techniques and stereological procedure was used to quantify labeled cells. Golgi-impregnation method was used to evaluate changes in dendritic spines in DG. Hypericum perforatum (30 mg/Kg) has been administered for 3 weeks and then neural development in the adult hippocampus and behavioral changes have been examined. Results The anxiety/depressive-like state due to chronic corticosterone treatment was reversed by exogenous administration of Hypericum perforatum; the proliferation of progenitor cells in mice hippocampus was significantly reduced under chronic corticosterone treatment, whereas a long term treatment with Hypericum perforatum prevented the corticosterone-induced decrease in hippocampal cell proliferation. Corticosterone-treated mice exhibited a reduced spine density that was ameliorated by Hypericum perforatum administration. Conclusion These results provide evidence of morphological adaptations occurring in mature hippocampal neurons that might underlie resilient responses to chronic stress and contribute to the therapeutic effects of chronic Hypericum perforatum treatment.

Some species of Cnidarians, well known venomous organisms, are able to induce serious health problems as well as economic and social trouble. A lot of data show that cnidarian venoms can be cytotoxic to cultured cells. Therefore, a priority of the research is to find tools which could counteract the damaging activity of venoms. In this connection, the modulatory effects exerted by extracts of plants Ananas comosus (L.) and Carica papaya (L.) on cytotoxicity of heterotrichous microbasic eurytele nematocysts isolated from the jellyfish Pelagia noctiluca was evaluated. The nematocyst extract induced strong cytotoxicity at highest tested doses with reduction of cell survival below 40% and IC50 value of 40×103 nematocysts/mL. Both plant extracts significantly improved the survival of cells, so that the IC50 resulted 74×103 and 100×103 nematocysts/mL in the presence of A. comosus and C. papaya extracts, respectively, both used at 10 and 100 μg/mL. Taking into account that heterotrichous microbasic eurytele nematocysts are present mainly in tentacles, which Pelagia noctiluca utilizes both for predation and defence, this result is particularly interesting from both ecological and sanitary point of view and demonstrates the potential of these plants extracts against cnidarian venoms. [ABSTRACT FROM AUTHOR]

Preconditioning (PC) is a cell adaptive response to oxidative stress and, with regard to neurons, can be considered as a neuroprotective strategy. The aim of the present study was to verify how neuronal‐like differentiated SH‐SY5Y cells adapt to a mild and transient H2O2‐induced oxidative stress and, hence, whether may be considered as more sensitive cell model to study PC pathways. A first screening allowed to define H2O2 concentrations for PC (10μM‐50μM), applied before damage(100μM H2O2). Cell viability measured 24 hours after 100μM H2O2–induced damage was ameliorated by 24‐hour pre‐exposure to low‐concentration H2O2 (10μM‐30μM) with cell size as well restored. Markers for apoptosis (Bcl‐2 and Bad), inflammation (iNOS), and redox system (MnSOD) were also determined, showing that, in cells pre‐exposed to 10μM H2O2 and then submitted to 100μM H2O2, Bcl‐2 levels were higher, Bad and iNOS levels were lower than those observed in damaged cells, and MnSOD levels were unchanged. Such findings show that (1) neuronal‐like differentiated SH‐SY5Y cells are a suitable model to investigate PC response and more sensitive to the effect of a mild and transient H2O2‐induced oxidative stress with respect to other neuronal cells; (2) 10μM H2O2–induced PC is mediated by apoptotic and inflammatory pathways, unlike antioxidant system; (3) such neuroprotective strategy and underlying signals proven in neuronal‐like differentiated SH‐SY5Y cells may contribute to understand in vivo PC mechanisms and to define a window for pharmacological intervention, namely, related to ischemic brain damage. Significance of the study: Neuronal‐like differentiated SH‐SY5Y cells are a suitable model to investigate PC, an endogenous neuroprotective response to a mild and transient H2O2‐induced oxidative stress, elicited by 24‐hour exposure to very low H2O2 concentrations and mediated by both apoptotic and inflammatory pathways. This model reflects in vivo PC mechanisms occurring after brain trauma and provides novel information about pathways and time of protection useful for an appropriate pharmacological intervention. [ABSTRACT FROM AUTHOR]

Preconditioning (PC) is an adaptive response to a mild and transient oxidative stress, shown for the first time in myocardial cells and not described in erythrocytes so far. The possible adaptation of human erythrocytes to hydrogen peroxide (HO)-induced oxidative stress has been here verified by monitoring one of band 3 protein functions, i.e., Cl/HCO exchange, through rate constant for SO uptake measurement. With this aim, erythrocytes were exposed to a mild and transient oxidative stress (30 min to either 10 or 100 μM HO), followed by a stronger oxidant condition (300- or, alternatively, 600-μM HO treatment). SO uptake was measured by a turbidimetric method, and the possible role of catalase (CAT, significantly contributing to the anti-oxidant system in erythrocytes) in PC response has been verified by measuring the rate of HO degradation. The preventive exposure of erythrocytes to 10 μM HO, and then to 300 μM HO, significantly ameliorated the rate constant for SO uptake with respect to 300 μM HO alone, showing thus an adaptive response to oxidative stress. Our results show that (i) SO uptake measurement is a suitable model to monitor the effects of a mild and transient oxidative stress in human erythrocytes, (ii) band 3 protein anion exchange capability is retained after 10 μM HO treatment, (iii) PC response induced by the 10 μM HO pretreatment is clearly detected, and (iv) PC response, elicited by low-concentrated HO, is mediated by CAT enzyme and does not involve band 3 protein tyrosine phosphorylation pathways. Erythrocyte adaptation to a short-term oxidative stress may serve as a basis for future studies about the impact of more prolonged oxidative events, often associated to aging, drug consumption, chronic alcoholism, hyperglycemia, or neurodegenerative diseases. [ABSTRACT FROM AUTHOR]

Investigates the activation properties of in situ nematocytes of Pelagia noctiluca of Scyphozoa. Calcium ion dependence of nematocyte activation; Inhibitory action of gadolinium.

Preconditioning (PC) is a cell adaptive response to oxidative stress and, with regard to neurons, can be considered as a neuroprotective strategy. The aim of the present study was to verify how neuronal-like differentiated SH-SY5Y cells adapt to a mild and transient H 2 O 2 -induced oxidative stress and, hence, whether may be considered as more sensitive cell model to study PC pathways. A first screening allowed to define H 2 O 2 concentrations for PC (10μM-50μM), applied before damage(100μM H 2 O 2 ). Cell viability measured 24 hours after 100μM H 2 O 2 -induced damage was ameliorated by 24-hour pre-exposure to low-concentration H 2 O 2 (10μM-30μM) with cell size as well restored. Markers for apoptosis (Bcl-2 and Bad), inflammation (iNOS), and redox system (MnSOD) were also determined, showing that, in cells pre-exposed to 10μM H 2 O 2 and then submitted to 100μM H 2 O 2 , Bcl-2 levels were higher, Bad and iNOS levels were lower than those observed in damaged cells, and MnSOD levels were unchanged. Such findings show that (1) neuronal-like differentiated SH-SY5Y cells are a suitable model to investigate PC response and more sensitive to the effect of a mild and transient H 2 O 2 -induced oxidative stress with respect to other neuronal cells; (2) 10μM H 2 O 2 -induced PC is mediated by apoptotic and inflammatory pathways, unlike antioxidant system; (3) such neuroprotective strategy and underlying signals proven in neuronal-like differentiated SH-SY5Y cells may contribute to understand in vivo PC mechanisms and to define a window for pharmacological intervention, namely, related to ischemic brain damage., Significance of the Study: Neuronal-like differentiated SH-SY5Y cells are a suitable model to investigate PC, an endogenous neuroprotective response to a mild and transient H 2 O 2 -induced oxidative stress, elicited by 24-hour exposure to very low H 2 O 2 concentrations and mediated by both apoptotic and inflammatory pathways. This model reflects in vivo PC mechanisms occurring after brain trauma and provides novel information about pathways and time of protection useful for an appropriate pharmacological intervention., (Copyright © 2018 John Wiley & Sons, Ltd.)

Marine animals represent a source of novel bioactive compounds considered as a good research model, whose mechanism of action is intriguing and still under debate. Among stinging animals, Cnidarians differentiated highly specialized cells, termed nematocytes, containing a capsule fluid with toxins and an inverted tubule, synergistically responsible for mechanisms of defence and predation. Such compounds include proteins and secondary metabolites with toxic action. With the aim of better elucidating the effects of Cnidarian venom upon cell targets, this short review reports on the current knowledge about the toxicological activity of venom extracted from nematocysts of the jellyfish Pelagia noctiluca, whose notable blooming is well known in the Strait of Messina (Italy). The effects on cultured cells, from both mammals and invertebrates, and erythrocytes are here being considered. What is known about the biological activity of Pelagia noctiluca crude venom accounts for a powerful biological activity at different levels, suggesting that cell damage may be due to a pore formation mechanism on cell membrane target leading to osmotic lysis, and /or to oxidative stress events. In this light, the study of venom activity may contribute to: i) validate suitable biological assays for venom testing; ii) elucidate cell function features; iii) understand the pathophysiology of envenoming.