Effects of photobiomodulation on oxidative stress in rats with type 2 diabetes mellitus.

The present study aimed to evaluate photobiomodulation effects on oxidative stress in type 2 diabetes mellitus (DM2). Thirty-one male Wistar rats were used and divided into 4 groups: group 1 - animals without diabetes mellitus 2 without laser 21 J/cm2 (C-SHAM), group 2 - animals with diabetes mellitus 2 without laser 21 J/cm2 (C-DM2), group 3 - animals without diabetes mellitus 2 with laser 21 J/cm2 (L-SHAM), group 4 - animals with diabetes mellitus 2 with laser 21 J/cm2 (L-DM2). The protocol was performed 5 days/week, for 6 weeks. The animals that received photobiomodulation had one dose irradiated at two spots in the right gastrocnemius muscle. Twenty-four hours after the last intervention, the animals were euthanized. Heart, diaphragm, liver, right gastrocnemius, plasma, kidneys, weighed, and stored for further analysis. In rats with DM2, photobiomodulation promoted a decrease in thiobarbituric acid reactive substance assay (TBARS) in plasma levels. On the other hand, photobiomodulation demonstrated an increase in non-protein thiol levels (NPSH) in the heart, diaphragm and gastrocnemius. Moreover, photobiomodulation produced in the heart, diaphragm and plasma levels led to an increase in superoxide dismutase (SOD). Interestingly, photobiomodulation was able to increase superoxide dismutase in rats without DM2 in the heart, diaphragm, gastrocnemius and kidneys. These findings suggested that 6 weeks of photobiomodulation in rats with DM2 promoted beneficial adaptations in oxidative stress, with a decrease in parameters of oxidant activity and an increase in antioxidant activity.

JM-20 Treatment After Mild Traumatic Brain Injury Reduces Glial Cell Pro-inflammatory Signaling and Behavioral and Cognitive Deficits by Increasing Neurotrophin Expression.

Traumatic brain injury (TBI) is considered a public health problem and is often related to motor and cognitive disabilities, besides behavioral and emotional changes that may remain for the rest of the subject's life. Resident astrocytes and microglia are the first cell types to start the inflammatory cascades following TBI. It is widely known that continuous or excessive neuroinflammation may trigger many neuropathologies. Despite the large numbers of TBI cases, there is no effective pharmacological treatment available. This study aimed to investigate the effects of the new hybrid molecule 3-ethoxycarbonyl-2-methyl-4-(2-nitrophenyl)-4,11-dihydro1H-pyrido[2,3-b][1,5]benzodiazepine (JM-20) on TBI outcomes. Male Wistar rats were submitted to a weight drop model of mild TBI and treated with a single dose of JM-20 (8 mg/kg). Twenty-four hours after TBI, JM-20-treated animals showed improvements on locomotor and exploratory activities, and short-term memory deficits induced by TBI improved as well. Brain edema was present in TBI animals and the JM-20 treatment was able to prevent this change. JM-20 was also able to attenuate neuroinflammation cascades by preventing glial cells-microglia and astrocytes-from exacerbated activation, consequently reducing pro-inflammatory cytokine levels (TNF-α and IL-1ß). BDNF mRNA level was decreased 24 h after TBI because of neuroinflammation cascades; however, JM-20 restored the levels. JM-20 also increased GDNF and NGF levels. These results support the JM-20 neuroprotective role to treat mild TBI by reducing the initial damage and limiting long-term secondary degeneration after TBI.

Relevance of Mitochondrial Dysfunction in the Reserpine-Induced Experimental Fibromyalgia Model.

Fibromyalgia (FM) is one of the most common musculoskeletal pain conditions. Although the aetiology of FM is still unknown, mitochondrial dysfunction and the overproduction of reactive oxygen intermediates (ROI) are common characteristics in its pathogenesis. The reserpine experimental model can induce FM-related symptoms in rodents by depleting biogenic amines. However, it is unclear whether reserpine causes other pathophysiologic characteristics of FM. So far, no one has investigated the relevance of mitochondrial dysfunction in the reserpine-induced experimental FM model using protection- and insult-based mitochondrial modulators. Reserpine (1 mg/kg) was subcutaneously injected once daily for three consecutive days in male Swiss mice. We carried out analyses of reserpine-induced FM-related symptoms, and their modulation by using mitochondrial insult on ATP synthesis (oligomycin; 1 mg/kg, intraperitoneally) or mitochondrial protection (coenzyme Q10; 150 mg/kg/5 days, orally). We also evaluated the effect of reserpine on mitochondrial function using high-resolution respirometry and oxidative status. Reserpine caused nociception, loss in muscle strength, and anxiety- and depressive-like behaviours in mice that were consistent with clinical symptoms of FM, without inducing body weight and temperature alterations or motor impairment. Reserpine-induced FM-related symptoms were increased by oligomycin and reduced by coenzyme Q10 treatment. Reserpine caused mitochondrial dysfunction by negatively modulating the electron transport system and mitochondrial respiration (ATP synthesis) mainly in oxidative muscles and the spinal cord. These results support the role of mitochondria in mediating oxidative stress and FM symptoms in this model. In this way, reserpine-inducing mitochondrial dysfunction and increased production of ROI contribute to the development and maintenance of nociceptive, fatigue, and depressive-like behaviours.

Guanosine protects against behavioural and mitochondrial bioenergetic alterations after mild traumatic brain injury.

Traumatic brain injury (TBI) constitutes a heterogeneous cerebral insult induced by traumatic biomechanical forces. Mitochondria play a critical role in brain bioenergetics, and TBI induces several consequences related with oxidative stress and excitotoxicity clearly demonstrated in different experimental model involving TBI. Mitochondrial bioenergetics alterations can present several targets for therapeutics which could help reduce secondary brain lesions such as neuropsychiatric problems, including memory loss and motor impairment. Guanosine (GUO), an endogenous neuroprotective nucleoside, affords the long-term benefits of controlling brain neurodegeneration, mainly due to its capacity to activate the antioxidant defense system and maintenance of the redox system. However, little is known about the exact protective mechanism exerted by GUO on mitochondrial bioenergetics disruption induced by TBI. Thus, the aim of this study was to investigate the effects of GUO in brain cortical and hippocampal mitochondrial bioenergetics in the mild TBI model. Additionally, we aimed to assess whether mitochondrial damage induced by TBI may be related to behavioral alterations in rats. Our findings showed that 24 h post-TBI, GUO treatment promotes an adaptive response of mitochondrial respiratory chain increasing oxygen flux which it was able to protect against the uncoupling of oxidative phosphorylation (OXPHOS) induced by TBI, restored the respiratory electron transfer system (ETS) established with an uncoupler. Guanosine treatment also increased respiratory control ratio (RCR), an indicator of the state of mitochondrial coupling, which is related to the mitochondrial functionality. In addition, mitochondrial bioenergetics failure was closely related with locomotor, exploratory and memory impairments. The present study suggests GUO treatment post mild TBI could increase GDP endogenous levels and consequently increasing ATP levels promotes an increase of RCR increasing OXPHOS and in substantial improve mitochondrial respiration in different brain regions, which, in turn, could promote an improvement in behavioral parameters associated to the mild TBI. These findings may contribute to the development of future therapies with a target on failure energetic metabolism induced by TBI.

The insertion of functional groups in organic selenium compounds promote changes in mitochondrial parameters and raise the antibacterial activity.

Organic selenium compounds are widely associated with numerous pharmacological properties. However, selenium compounds, such as Ebselen (Ebs) and Diphenyl Diselenide (DPDS), could interact with mitochondrial respiratory complexes, especially with thiol groups. The present study evaluated whether the insertion of functional groups, o-methoxy, and p-methyl on organic selenium compounds promotes changes in mitochondrial functioning parameters and whether this is related to antibacterial activity. Here we tested some in vitro parameters after the exposure of mitochondria to different concentrations of ß-selenoamines 1-phenyl-3-(p-tolylselanyl)propan-2-amine (C1) and 1-(2-methoxyphenylselanyl)-3-phenylpropan-2-amine (C2) and analogs of DPDS 1,2-bis(2-methoxyphenyl)diselenide (C3) and 1,2-bisp-tolyldiselenide (C4). We also evaluated the antibacterial activity of ß-selenoamines and diselenides against Methicillin-resistant Staphylococcus aureus and Escherichia coli. Our results showed that o-methoxy insertion increased the antioxidant properties, without affecting the mitochondrial membrane potential. The compounds with a p-methyl insertion affected the mitochondrial membrane potential and significantly decreased the State III respiration and RCR. Besides, the p-methyl compounds presented antibacterial activity at lower concentrations than those shown in o-methoxy, precisely by the same mechanism that promotes damage to thiol groups and better absorption in gram-positive bacteria due to their relationship with cell wall constituents. Finally, our study confirms that structural modifications in organic selenium compounds provide changes in mitochondrial functioning but also raise their antibacterial effect. This strategy can be used as a target for the development of new enough potent antibacterial to restrict the advance of resistant bacterial infections.

Combined platelet-rich plasma and cold water immersion treatment minimize the damage following a skeletal muscle stretch injury in rats.

The skeletal muscle stretch injuries are commonly observed in sports. In order to stimulate tissue healing, the platelet-rich plasma (PRP) and cold water immersion (CWI) are widely used in clinical practice. This study investigated the effects of isolated or combined PRP and/or CWI on the oxidative damage determined by a stretch injury induced in gastrocnemius muscle of rats. PRP and CWI are applied immediately after the injury, and the biochemical analysis was performed after 1, 3, 5, or 7 days. The levels of o thiobarbituric acid reactive substances and oxidized dichlorofluorescein were significantly increased, both in skeletal muscle tissue and erythrocytes preparations, and the combined PRP and CWI minimized these parameters. Moreover, combined PRP and CWI were more effective than the isolated treatments to increase catalase activity, also the ratio of reduced/oxidized glutathione, and the non-protein thiols (-SH) group levels. In conclusion, we could infer that the combination of these regular treatments used in an isolated form shows a great potential for treatments of muscular injuries.

Acute Exposure to Permethrin Modulates Behavioral Functions, Redox, and Bioenergetics Parameters and Induces DNA Damage and Cell Death in Larval Zebrafish.

Permethrin (PM) is a synthetic pyrethroid insecticide widely used as domestic repellent. Damage effects to nontarget organisms have been reported, particularly in the early stages of development. Studies indicate redox unbalance as secondary PM effect. Therefore, our goal was to investigate the acute PM effects on larval zebrafish. Larvae (6 days postfertilization) were exposed to PM (25-600 µg/L) during 24 hours, and 50% lethal concentration was estimated. For subsequent assays, the sublethal PM concentrations of 25 and 50 µg/L were used. PM increased anxiety-like behaviors according to the Novel Tank and Light-Dark tests. At the molecular level, PM induced increased ROS, which may be related to the increased lipid peroxidation, DNA damage, and apoptosis detected in PM-exposed organisms. In parallel, upregulation of the antioxidant system was detected after PM exposure, with increased superoxide dismutase, glutathione S-transferase and glutathione reductase activities, and thiol levels. The increased of Nrf2 target genes and the activation of an electrophile response element-driven reporter Tg(EPRE:LUC-EGFP) suggest that the Nrf2 pathway can mediate a fast response to PM, leading to antioxidant amplification. By using high-resolution respirometry, we found that exposure to PM decreased the oxygen consumption in all respiratory stages, disrupting the oxidative phosphorylation and inhibiting the electron transfer system, leading to decrease in bioenergetics capacity. In addition, PM led to increases of residual oxygen consumption and changes in substrate control ratio. Glucose metabolism seems to be affected by PM, with increased lactate dehydrogenase and decreased citrate synthase activities. Taken together, our results demonstrated the adverse effects of acute sublethal PM concentrations during larval development in zebrafish, causing apparent mitochondrial dysfunction, indicating a potential mechanism to redox unbalance and oxidative stress, which may be linked to the detected cell death and alterations in normal behavior patterns caused by acute PM exposure.

Guanosine protects against Ca2+-induced mitochondrial dysfunction in rats.

Mitochondria play an important role in cell life and in the regulation of cell death. In addition, mitochondrial dysfunction contributes to a wide range of neuropathologies. The nucleoside Guanosine (GUO) is an endogenous molecule, presenting antioxidant properties, possibly due to its direct scavenging ability and/or from its capacity to activate the antioxidant defense system. GUO demonstrate a neuroprotective effect due to the modulation of the glutamatergic system and maintenance of the redox system. Thus, considering the few studies focused on the direct effects of GUO on mitochondrial bioenergetics, we designed a study to evaluate the in vitro effects of GUO on rat mitochondrial function, as well as against Ca2+-induced impairment. Our results indicate that GUO prevented mitochondrial dysfunction induced by Ca2+ misbalance, once GUO was able to reduce mitochondrial swelling in the presence of Ca2+, as well as ROS production and hydrogen peroxide levels, and to increase manganese superoxide dismutase activity, oxidative phosphorylation and tricarboxylic acid cycle activities. Our study indicates for the first time that GUO could direct prevent the mitochondrial damage induced by Ca2+ and that these effects were not related to its scavenging properties. Our data indicates that GUO could be included as a new pharmacological strategy for diseases linked to mitochondrial dysfunction.

Antioxidant protection by ß-selenoamines against thioacetamide-induced oxidative stress and hepatotoxicity in mice.

Thioacetamide (TAA) is a hepatotoxin that rapidly triggers the necrotic process and oxidative stress in the liver. Nevertheless, organic selenium compounds, such as ß-selenoamines, can be used as pharmacological agents to diminish the oxidative damage. Thus, the aim of this study was to investigate the protective effect of the antioxidant ß-selenoamines on TAA-induced oxidative stress in mice. Here, we observed that a single intraperitoneal injection of TAA (200 mg/kg) dramatically elevated some parameters of oxidative stress, such as lipid peroxidation and reactive oxygen species (ROS) production, as well as depleted cellular antioxidant defenses. In addition, TAA-induced edema and morphological changes in the liver, which correlate with high serum aspartate and alanine aminotransferase enzyme activities, and a decrease in cell viability. Conversely, a significant reduction in liver lipid peroxidation, ROS production, and edema was observed in animals that received an intraperitoneal injection of ß-selenoamines (15.6 mg/kg) 1 h after TAA administration.

Platelet-rich plasma reduces the oxidative damage determined by a skeletal muscle contusion in rats.

Platelet-rich plasma (PRP) has received increasing attention and is widely used in clinical practice in order to stimulate human tissue healing. Contusions are very common injuries observed in sports and affect the function of the musculoskeletal system. This study investigated the effects of PRP on the oxidative damage determined by a contusion induced in gastrocnemius muscle of rats. PRP was injected intramuscularly immediately after injury and every 48 h, and the biochemical analysis was performed 1, 3, 5, or 7 days after the contusion onset in order to evaluate the changes characteristics of the healing process. The contusion increased the levels of oxidative stress markers such as thiobarbituric acid reactive substances and oxidized dichlorofluorescein both in skeletal muscle tissue and erythrocytes preparations, and PRP treatment significantly reduced these oxidative damage markers. Furthermore, the contusion decreased the cellular viability in the site of the lesion and PRP was effective in diminishing this effect. Moreover, PRP increased the levels of enzymatic antioxidants superoxide dismutase and catalase activities in the injured muscle, and also the non-protein thiols (-SH) group levels in erythrocytes. In conclusion PRP, in the form that was used in this study, was able to modulate the oxidative damage determined by a classical skeletal muscle injury possibly by reducing the impairment of myocytes mitochondrial function and improving their endogenous antioxidant defense systems.