Carbomer Hydrogels with Microencapsulated α-Tocopherol: Focus on the Biocompatibility of the Microcapsules, Topical Application Attributes, and In Vitro Release Study.

The microencapsulation of α-tocopherol based on the complex coacervation of low-molecular-weight chitosan (LMWC) and sodium lauryl ether sulphate (SLES) without harmful crosslinkers can provide biocompatible carriers that protect it from photodegradation and air oxidation. In this study, the influence of the microcapsule wall composition on carrier performance, compatibility with a high-water-content vehicle for topical application, and release of α-tocopherol were investigated. Although the absence of aldehyde crosslinkers decreased the encapsulation efficiency of α-tocopherol (~70%), the variation in the LMWC/SLES mass ratio (2:1 or 1:1) had no significant effect on the moisture content and microcapsule size. The prepared microcapsule-loaded carbomer hydrogels were soft semisolids with pseudoplastic flow behavior. The integrity of microcapsules embedded in the hydrogel was confirmed by light microscopy. The microcapsules reduced the pH, apparent viscosity, and hysteresis area of the hydrogels, while increasing their spreading ability on a flat inert surface and dispersion rate in artificial sweat. The in vitro release of α-tocopherol from crosslinker-free microcapsule-loaded hydrogels was diffusion-controlled. The release profile was influenced by the LMWC/SLES mass ratio, apparent viscosity, type of synthetic membrane, and acceptor medium composition. Better data quality for the model-independent analysis was achieved when a cellulose nitrate membrane and ethyl alcohol 60% w/w as acceptor medium were used.

Magnesium suppresses in vivo oxidative stress and ex vivo DNA damage induced by protracted ACTH treatment in rats.

Oxidative stress, arising from disrupted balance between reactive oxygen/nitrogen species (ROS/RNS) and antioxidant defences, has been implicated in the pathogenesis of stress-related disorders. There is a growing body of evidence that supports the relationship between the activity of the hypothalamic-pituitary-adrenal (HPA) stress system, oxidative stress and magnesium (Mg) homeostasis. The present study aimed to explore the gap in our current understanding of antigenotoxic and protective effects of Mg supplementation against excessive ROS production in male rats during chronic treatment with adrenocorticotropic hormone (ACTH). Our findings show that exposure to exogenous ACTH (10 µg/day, s.c., for 21 days), as one of the key mediators of the HPA axis and stress response, produced an increase in superoxide anion levels and a decrease in superoxide dismutase activity in plasma. We observed that Mg supplementation, starting seven days prior to ACTH treatment and lasting 28 days (300 mg/L of drinking water, per os), abolished these effects in experimental animals. Moreover, our study reveals that ACTH increased the susceptibility of peripheral blood lymphocytes to ex vivo H2O2-induced total and high-level oxidative DNA damage, while Mg completely reversed these effects. Collectively, these results highlight the promising role of Mg in stress-related conditions accompanied by increased oxidative stress in animals and support further investigation using human dietary trials.

Specific Changes in the Mammalian Gut Microbiome as a Biomarker for Oxytocin-Induced Behavioral Changes.

Prolonged exposure to psychiatric pharmacological agents is often associated with marked gastrointestinal phenomena, including changes in food intake, bowel motility, gastric emptying, and transit time. Those changes are reflected in the gut microbiota composition of the patient and can, therefore, be objectively measured. This is in contrast to the standard psychiatric evaluation of patients, which includes symptoms that are subjectively assessed (i.e., mood, anxiety level, perception, thought disorders, etc.). The association between a drug's effect on the microbiota and psychiatric symptoms may allow for quantifiable surrogate markers of treatment effectiveness. Changes in the levels of specific drug-sensitive bacterial species can, thus, potentially serve as biomarkers for the intake and effectiveness of psychiatric drugs. Here, we show substantial microbiota changes that were associated with oxytocin administration and the decreased anxiety/depression-like behaviors it conferred in a rat model of corticosterone-induced stress. Compared with oxytocin, citalopram produced more minor effects on the rats' microbiota. Alterations in the gut microbiota may, therefore, reflect the consumption and effectiveness of some psychiatric drugs.

Synergy of oxytocin and citalopram in modulating Itgb3/Chl1 interplay: Relevance to sensitivity to SSRI therapy.

Intranasal treatment with oxytocin showed beneficial effects in post-traumatic stress disorder and autism spectrum disorders; however, it was not investigated as much in depression. Keeping in mind the favorable effects of oxytocin on animal models of anxiety and depression, we postulated that synergy between prescribed first choice drugs, selective serotonin reuptake inhibitors (SSRIs) and oxytocin could improve the treatment outcome compared with SSRI monotherapy. Our previous in vitro genome-wide transcriptomic study on human lymphoblastoid cell lines exposed to paroxetine resulted in increase of integrin ß3 (ITGB3) gene expression, and further, ITGB3/CHL1 expression ratio was hypothesized to influence the sensitivity to SSRIs. The aim of this report was to explore molecular mechanisms behind the antidepressant-like oxytocin effect, alone and in synergy with citalopram, on behavioral and molecular level in corticosterone treated rats, a paradigm used to model anxiety and depression in animals. Oxytocin treatment (1) ameliorated corticosterone-induced reduction of neurogenesis and number of parvalbumin-positive interneurons in the hippocampal CA1 region, (2) enhanced anxiolytic- and antidepressant-like effects of citalopram in the open field test, and (3) the SSRI/oxytocin synergy persisted in reversing the reduction of the Itgb3 gene expression and increased Itgb3/Chl1 ratio in the prefrontal cortices. These results support the existence of synergy between citalopram and oxytocin in reversing the molecular and behavioral changes induced by corticosterone treatment and point to possible molecular mechanisms behind antidepressant-like effect of oxytocin.

Acth-induced model of depression resistant to tricyclic antidepressants: Neuroendocrine and behavioral changes and influence of long-term magnesium administration.

Magnesium (Mg), is not only a modulator of the glutamatergic NMDA receptors' affinity, it also prevents HPA axis hyperactivity, thus possibly being implicated in neurobiological features of mood disorders. Further uncovering of molecular mechanisms underlying magnesium's proposed effects is needed due to the recent shift in research of treatment resistant depression (TRD) towards glutamatergic pathways. Here, we applied Mg via drinking water for 28 days (50 mg/kg/day), in ACTH-treated rats, an established animal model of depression resistant to tricyclic antidepressants. Using this model in male rats we measured (1) changes in hippocampal neurogenesis and behavioral alterations, (2) adrenal hormones response to acute stress challenge and (3) levels of biometals involved in regulation of monoamines turnover in rat prefrontal cortex. Our results support beneficial behavioral impact of Mg in TRD model together with increased hippocampal neurogenesis and BDNF expression. Furthermore, Mg prevented ACTH-induced disruption in HPA axis function, by normalizing the levels of plasma ACTH, corticosterone and interleukin-6, and by increasing the peripheral release of adrenaline, noradrenaline and serotonin after the acute stress challenge. Finally, the influence on copper/zinc ratio suggested probable magnesium's involvement in monoamine turnover in PFC. Our findings provide further insights into the possible pathways implicated in the behavioral modulation effects of Mg, as well as its central and peripheral effects in ACTH-induced TRD model. Thus, further investigation of molecular signaling related to the glutamatergic transmission and role of Mg, could reveal prospects to novel treatment strategies that could be of particular importance for patients suffering from TRD.

A single dose of magnesium, as well as chronic administration, enhances long-term memory in novel object recognition test, in healthy and ACTH-treated rats.

Although a magnesium-mediated attenuation of memory deficits was reported in animal models of ageing and traumatic brain injury, a possible memory enhancement in healthy subjects has not been investigated yet. We used novel object recognition test (NORT) to examine the effects of acute (30 mg/kg) and chronic (50 mg/kg, 28 days) Mg-sulfate treatment on the long-term memory (LTM) in healthy adult male rats, and to test the sustainability of magnesium effects in the models of acute and chronic (21 days) ACTH administration (10 µg/animal), mimicking the stress- and depression-like conditions. A single dose of Mg-sulfate enhanced the LTM retrieval in the 24 h inter-trial NORT protocol, in healthy, as well as in rats acutely treated with ACTH. Memory enhancement was also detected after 4-week long Mg-sulfate intake, in both healthy and rats chronically treated with ACTH. While the present findings on procognitive effects of chronic Mg-sulfate treatment corroborate with those from studies on the therapeutic potential of Mg-threonate, the current study is the first to report on memory enhancement induced by a single dose of magnesium.

Oxytocin in corticosterone-induced chronic stress model: Focus on adrenal gland function.

Chronic stress conditions can lead to considerable and extensible changes in physiological and psychological performances, and in emergence of risk for various somatic diseases. On the other hand, the neuropeptide oxytocin is reported to increase the resistance of the organism to stress and modulate activity of autonomic nervous system. Chronic corticosterone administration is used as a rat model for a state observed in terms of chronic stress exposure, when negative feedback mechanism of hypothalamus-pituitary-adrenal axis activity is disrupted. In our study, we aimed to investigate whether chronic administration of oxytocin (10 IU/400µL/day for 14days, s.c.) influenced adrenal gland morphology and activity in adult male Wistar rats during long-term corticosterone administration via drinking water (100mg/L for 21days). We examined the influence of treatments on the levels of adrenal gland hormones, corticosterone, adrenaline and noradrenaline, as well as their response to an acute stress challenge evoked by 15-min forced swimming. In addition, the expression of two main monoamine transporters, the noradrenaline transporter (NAT) and vesicular monoamine transporter 2 (VMAT2) in adrenal medulla was measured in the rats exposed to acute stress. Our results showed that oxytocin treatment prevented corticosterone-induced decrease in body weight gain, attenuated adrenal gland atrophy by increasing glandular weight, and the area of the zona fasciculate and reticularis. Chronic corticosterone intake blunted the response of all measured hormones to acute stress, whereas concomitant oxytocin treatment reversed adrenaline and noradrenaline response to acute stress. Furthermore, in adrenal medulla, oxytocin produced significant vasodilatation and stimulated expression of both catecholamine transporters detected both on mRNA and protein level. Our data suggest that oxytocin, by reducing atrophy of adrenal gland, and by increasing catecholamine storage capacity, may be beneficial in conditions accompanied with high glucocorticoid levels, such as chronic stress exposure.

Hydrogen peroxide-induced oxidative damage in peripheral blood lymphocytes from rats chronically treated with corticosterone: The protective effect of oxytocin treatment.

Contemporary lifestyle is commonly associated with chronic stress, an environmental factor contributing to development of various psychological and somatic disorders. Increased levels of glucocorticoids, observed in the chronic stress, induce the production of reactive oxygen species leading to genotoxicity. The aim of this study was to investigate whether chronic administration of oxytocin (OXY) 10 IU/400 µL/day, s.c., for 14 days, a hormone presumed to exert antioxidant effect, may prevent DNA damage in the comet assay of peripheral blood lymphocytes of Wistar rats treated chronically with corticosterone (CORT) 100 mg/L ad libitum, per os, for 21 days, as well as, to influence some plasma oxidative stress parameters, i.e. levels of total lipid hydroperoxide (LOOH), and malondialdehyde (MDA), and the activity of antioxidative enzyme superoxide dismutase (SOD). Even though there was no reduction in overall number of damaged cells after oxytocin treatment only, the marked increase in total comet score (TCS) after incubation with H2O2 in CORT group compared to controls, was absent in the CORT + OXY experimental group. Furthermore, significant decrease of highly damaged cells compared to corticosterone group was noted. Chronic oxytocin administration thus protected lymphocytes from high intensity damage that leads to cellular death. In addition, treatment with OXY along with CORT, significantly decreased concentration of LOOH in plasma, and increased SOD compared to CORT treatment only. This finding corresponds well with current reports on beneficial effects of OXY in conditions of HPA axis hyperactivity, and supports the hypothesis of OXY-mediated antioxidant action.

Magnesium Supplementation Diminishes Peripheral Blood Lymphocyte DNA Oxidative Damage in Athletes and Sedentary Young Man.

Sedentary lifestyle is highly associated with increased risk of cardiovascular disease, obesity, and type 2 diabetes. It is known that regular physical activity has positive effects on health; however several studies have shown that acute and strenuous exercise can induce oxidative stress and lead to DNA damage. As magnesium is essential in maintaining DNA integrity, the aim of this study was to determine whether four-week-long magnesium supplementation in students with sedentary lifestyle and rugby players could prevent or diminish impairment of DNA. By using the comet assay, our study demonstrated that the number of peripheral blood lymphocytes (PBL) with basal endogenous DNA damage is significantly higher in rugby players compared to students with sedentary lifestyle. On the other hand, magnesium supplementation significantly decreased the number of cells with high DNA damage, in the presence of exogenous H2O2, in PBL from both students and rugby players, and markedly reduced the number of cells with medium DNA damage in rugby players compared to corresponding control nonsupplemented group. Accordingly, the results of our study suggest that four-week-long magnesium supplementation has marked effects in protecting the DNA from oxidative damage in both rugby players and in young men with sedentary lifestyle. Clinical trial is registered at ANZCTR Trial Id: ACTRN12615001237572.

ACTH, Cortisol and IL-6 Levels in Athletes following Magnesium Supplementation.

BACKGROUND: Physical exercise activates the hypothalamo-pituitary-adrenal (HPA) axis and induces the body's inflammatory response. Due to contemporary dietary habits and increased energy expenditure, athletes are susceptible to depletion of magnesium ions. The aim of our study was to investigate, through assessment of plasma ACTH, serum IL-6, and salivary/serum cortisol levels, if chronic magnesium supplementation might reduce damaging stress effects in amateur rugby players. METHODS: Rugby players (N=23) were randomly assigned to intervention and control group. Basal samples were collected before intervention group started a 4-week-long supplementation with magnesium (500 mg Mg/d). Blood and saliva sampling were done a day before the match (Day-1), on the morning of competition (Game), and during a six-day-long recovery period (Day1, Day3 and Day6). ACTH, serum/salivary cortisol, IL-6 and total/differential leukocytes counts were determined at each time point. RESULTS: There was a statistically significant increase in ACTH concentration in intervention group compared to control group, while reductions in cortisol concentrations between the two groups were the greatest at Day-1 (p < 0.01) and at the day of competition (Game) (p < 0.01). Our results revealed that magnesium completely abolished the increase in IL-6 level noted in control group on Day1 and Day3 vs. Day-1 (p < 0.01) and also diminished the rise in neutrophil/lymphocyte ratio in intervention group vs. control group (p < 0.01). CONCLUSIONS: These results suggest the possibly important influence magnesium supplementation might have on the change of parameters of HPA axis activity and reduction of immune response activation following strenuous physical exercise such as a rugby game.