The ameliorative effect of midazolam on empathy-like behavior in old rats.

Although studies suggest that cognitive functions in the elderly are impaired, elderly people tend to be more successful and wiser in solving emotional problems. In empathy-like behavior models, the observer rat rescues the distressed cage mate by displaying emotional and cognitive ability. The aim of the study was to investigate the changes in empathy-like behavior in older rats in comparison to adult rats. In addition, we wanted to determine the effects of alterations in neurochemicals (such as corticosterone, oxytocin, vasopressin, and their receptor levels) and emotional situations on this behavior. In our study, we initially completed empathy-like behavior tests and emotional tests (open field, elevated plus maze) and performed neurochemical examinations in the serum and brain tissues. In the second step of research, we applied a midazolam (benzodiazepine) treatment to examine the effect of anxiety on empathy-like behavior. In the old rats, we observed that empathy-like behavior deteriorated, and anxiety signs were more pronounced. We detected a positive correlation between the latency in empathy-like behavior and corticosterone levels and v1b receptor levels. The midazolam effect on empathy-like behavior was attenuated by flumazenil (a benzodiazepine receptor antagonist). The recordings of ultrasonic vocalization showed frequencies around 50 kHz emitted by the observer and this was associated with the expectation of social contact. Our results state that compared to adult rats, old rats were more concerned and failed during empathy-like behavior. Midazolam may improve this behavior by anxiolysis.

A combination of ketogenic diet and voluntary exercise ameliorates anxiety and depression-like behaviors in Balb/c mice.

The positive effects of both ketogenic diet (KD) and regular voluntary exercise on anxiety and depression behavior have been recently reported in rodent animals, but the effects of pairing a KD with exercise on depression and anxiety are unknown. In this study, we aimed to investigate the effects of combination of KD and regular voluntary exercise on anxiety and depression-like behavior in Balb/c mice. We've demostrated that anxiety and depression levels decreased in KD-exercised (KD-Ex) mice. ß-hydroxybutyrate (BHB) levels increased while glucose, insulin levels and LDL/HDL ratio decreased in KD-Ex mice. There was a negative correlation between BHB and the time spent in the closed arms of elevated plus maze (EPM) or the time spent in periphery walls of open field test (OFT) and the immobility time in forced swim test (FST) which all of them are indicators of low depression and anxiety levels. There was a positive correlation between LDL/HDL ratio and the time spent in the closed arms of EPM or the immobility time in FST. The immobility time in FST was positively correlated with insulin while the mobility time in FST was negatively correlated with glucose. In conclusion, these results suggest that decline in anxiety and depression-like behaviors resulted from KD with regular voluntary exercise may be associated with increased BHB levels and decreased LDL/HDL ratio and insulin or glucose levels. Further research is necessary for our understanding of the mechanisms by which pairing a KD with voluntary exercise influences brain and behavior.

Magnesium Citrate Increases Pain Threshold and Reduces TLR4 Concentration in the Brain.

Magnesium is being investigated in various clinical conditions and has shown to be effective in some chronic pain models. However, it is not clear if oral magnesium use affects pain perception in acute pain. TLR4's (toll-like receptor) role in pain perception has emerged through its role in immune pathways and ion channels. The aim of this study is to investigate the effect of a single oral dose of magnesium citrate on pain conduction and whether with magnesium, the expression of TLR4 changes in the acute phase. Following a single dose of 66-mg/kg magnesium citrate administration to male Balb-c mice, pain perception (via hot-plate test), motor conduction (via electrophysiological recording, forelimb grip strength, rotarod and open-field tests), and emotional state (via elevated plus maze and forced swim test) were evaluated. In behavioral experiments, the control group was compared with applied magnesium for three different time groups (4, 8, 24 h). TLR4 expression was measured in four groups: control, magnesium (Mg), hot plate (HP), and Mg + HP. Hot plate latency was prolonged in the magnesium group (p < 0.0001) and electrophysiological recordings (p < 0.001) and forelimb grip strength measurement (p < 0.001) determined motor latency. Compared with the untreated hot plate group, TLR4 levels was lower in the brain (p = 0.023) and higher in the sciatic nerve (p = 0.001) in the magnesium-treated hot plate group. Consequently, the study indicated a single dose of magnesium citrate appeared to cause weakening in the transmission and perception of nociceptive pain. TLR4 may act as a regulator in magnesium's effects on pain perception.

Regular aerobic exercise increased VEGF levels in both soleus and gastrocnemius muscles correlated with hippocampal learning and VEGF levels.

Physical exercise improves learning and memory abilities by increasing the levels of several growth factors in the hippocampus. One growth factor, vascular endothelial growth factor (VEGF), is primarily produced in the muscles and not only increases in the periphery during exercise but can also cross the blood-brain barrier. The aim of this study is to investigate the effects of regular aerobic chronic exercise on different types of muscle fibers and the relationships between learning/memory and muscle induced-VEGF. Following a one-week adaptation period, male rats underwent treadmill training at a speed of 8 m/min for 30 min daily, 3 days a week for 6 weeks. Memory functions were evaluated using the Morris water maze. VEGF, superoxide dismutase (SOD), glutathione peroxidase (GPx), and malondialdehyde (MDA) levels were measured in type 1 and type 2 muscle fibers and VEGF levels were also measured in the hippocampus. Exercise positively affected both learning and memory and also increased VEGF levels in both muscle fiber types. Muscle VEGF levels positively correlate with hippocampal learning and hippocampal VEGF levels. Exercise reduced both SOD and MDA levels in type 1 and type 2 muscle fibers, whereas GPx levels decreased only in type 2 muscle fibers. Our findings suggest that regular aerobic exercise elevates VEGF levels and diminishes oxidative stress in both fiber types. Exercise-induced VEGF levels in both type 1 and 2 muscle fibers appear to be associated with the positive effect of exercise on learning and memory function and is accompanied by an increase in VEGF levels in the hippocampus. Further research is needed to elucidate the exact mechanism by which fiber type-specific VEGF mediates hippocampal neurogenesis and angiogenesis.Physical exercise improves learning and memory abilities by increasing the levels of several growth factors in the hippocampus. One growth factor, vascular endothelial growth factor (VEGF), is primarily produced in the muscles and not only increases in the periphery during exercise but can also cross the blood-brain barrier. The aim of this study is to investigate the effects of regular aerobic chronic exercise on different types of muscle fibers and the relationships between learning/memory and muscle induced-VEGF. Following a one-week adaptation period, male rats underwent treadmill training at a speed of 8 m/min for 30 min daily, 3 days a week for 6 weeks. Memory functions were evaluated using the Morris water maze. VEGF, superoxide dismutase (SOD), glutathione peroxidase (GPx), and malondialdehyde (MDA) levels were measured in type 1 and type 2 muscle fibers and VEGF levels were also measured in the hippocampus. Exercise positively affected both learning and memory and also increased VEGF levels in both muscle fiber types. Muscle VEGF levels positively correlate with hippocampal learning and hippocampal VEGF levels. Exercise reduced both SOD and MDA levels in type 1 and type 2 muscle fibers, whereas GPx levels decreased only in type 2 muscle fibers. Our findings suggest that regular aerobic exercise elevates VEGF levels and diminishes oxidative stress in both fiber types. Exercise-induced VEGF levels in both type 1 and 2 muscle fibers appear to be associated with the positive effect of exercise on learning and memory function and is accompanied by an increase in VEGF levels in the hippocampus. Further research is needed to elucidate the exact mechanism by which fiber type-specific VEGF mediates hippocampal neurogenesis and angiogenesis.

Carnitine protects the intestine against reperfusion injury in rats.

BACKGROUND: Although the negative effects of ischemia on anastomotic healing have been shown in many studies, there is no adequate information on the effects of reperfusion injury. Therefore, in this study, we investigated the effect of ischemia-reperfusion (IR) injury on intestinal anastomosis and the protective efficiency of carnitine in an experimental relatively short intestinal ischemia and long duration reperfusion model. METHODS: Animals were divided into three groups (n=14). Each group was separated into two subgroups. In subgroups A, morphologic injury and the number of perfused intestinal muscular microvessels were analyzed to show "no-reflow phenomenon." Intestinal resection and anastomosis were performed in subgroups B. Carnitine group (IRCarG) received 200 mg/kg intravenous carnitine 2 min prior to reperfusion. Malonyldialdehyde, nitric oxide levels in tissue and blood, collagen levels, bursting pressures, and histopathologic evaluation of anastomosis were measured in subgroups B. RESULTS: Morphologic damage was statistically lower, number of perfused microvessels and epithelial regeneration were statistically higher in IRCarG, compared with ischemia-reperfusion group (P=0.03, P=0.008, P=0.05, respectively). CONCLUSION: Carnitine application prior to reperfusion may reduce the severity of the reperfusion injury by preventing the occurrence of no-reflow phenomenon, increase the number of perfused microvessels in the ischemic intestine, and may improve epithelial regeneration in intestinal anastomosis.

The Chronic Use of Magnesium Decreases VEGF Levels in the Uterine Tissue in Rats.

Vascular endothelial growth factor (VEGF) is the most important regulator of angiogenesis which serves to provide sufficient blood supply, and can trigger both physiological and pathological angiogenesis. Recent studies have shown that VEGF increases in gynecological diseases (such as endometriosis, ovarian, and endometrial cancers) and is a prognostic factor in these pathologies. Therefore, VEGF should be maintained at appropriate levels. Magnesium is used in many gynecological practices (such as eclampsia, preeclampsia, dysmenorrhea, and climacteric symptoms) and the mechanisms of action are still under investigation. Redox status, which can be regulated by magnesium, was shown to affect VEGF expression. The aim of this study was to evaluate the effects of chronic magnesium use on VEGF and oxidative status in the uterus. Magnesium sulfate was administered to rats at doses of 30 mg/kg (intramuscular) for 2 weeks. VEGF, Superoxide dismutase (SOD), Glutathione peroxidase (GPx), and Malondialdehyde (MDA) levels were measured using ELISA; vascular and cellular alterations were determined by histology in the uterine tissue at the metoestrus phase. In the uterine tissue of Mg-treated subjects, magnesium levels increased while VEGF, SOD, GPx, and MDA levels decreased without histological changes. There was a negative correlation between uterine tissue magnesium levels and VEGF, SOD, GPx, and MDA levels. Consequently, the results of this study demonstrated that regular magnesium use decreased VEGF levels in uterus. Decreased VEGF levels were associated with decreased uterine oxidative stress. Chronic magnesium usage may protect the uterine tissue from certain diseases in which angiogenesis is critical.

Magnesium Acetyl Taurate Prevents Tissue Damage and Deterioration of Prosocial Behavior Related with Vasopressin Levels in Traumatic Brain Injured Rats.

AIM: To investigate the effects of different magnesium forms on tissue damage, cognitive and emotional behavioural impairment after mild traumatic brain injury (TBI). MATERIAL AND METHODS: Rats were divided into 5 groups (control, trauma, magnesium sulphate, magnesium citrate, magnesium acetyl taurate) and following head trauma, empathy-like behaviour, anxiety-like behaviour (elevated plus maze and open field tests), and depression (forced swim test) were measured. The rats were then sacrificed 12 days later. Oxytocin, vasopressin and receptors levels in the amygdala and prefrontal cortex regions were measured. Histopathological damage (with haematoxylin-eosin staining) and apoptosis (with caspase-3 immunohistochemistry) was evaluated. RESULTS: Following head trauma, anxiety-like behaviour and depression tests did not change; empathy-like behaviour deteriorated on the 3rd day and improved gradually on the 6th and 12th days. Oxytocin, vasopressin and vasopressin v1b receptor levels decreased in the amygdala; morphological damage and apoptosis were significant. Magnesium acetyl taurate effectively ameliorated histopathological deteriorations and improved vasopressin and v1b receptor levels in the amygdala. Transient deterioration of empathy-like behaviour was impeded only in magnesium taurate treatment. CONCLUSION: Magnesium acetyl taurate can be a promising candidate agent to prevent structural and functional damage in traumatic brain injury.

Dose-Dependent Absorption Profile of Different Magnesium Compounds.

Magnesium, one of the basic elements for the human body, is necessary for many physiological functions. Magnesium deficiency is widely observed as a result of the reduced nutrient content of foods, over-cooking, diseases, drugs, alcohol, and caffeine consumption. Taking a dietary supplement is necessary magnesium deficiency. It has been demonstrated that absorption of organic magnesium compounds is better than absorption of inorganic compounds. The aim of this study is to investigate transitions to tissues of different organic magnesium compounds in different doses and whether there is a difference in the organic acid-bounded compounds (magnesium citrate and magnesium malate) and the amino acid-bounded compounds (magnesium acetyl taurate and magnesium glycinate), associated with transition and bioavailability. In addition, the effects of split dosages of high doses in a high volume of solvent on tissue magnesium levels are being investigated, because galenic formulation problems are regarded to prepare convenient dosage that can be taken once a day. All magnesium compounds were administered as three different doses, 45, 135, and 405 mg/70 kg elemental magnesium, were given per orally to Balbc mice. In a second set of experiments, 405 mg/70 kg high dose was divided into two doses of 202.5 mg/70 kg each and administered every 12 h. Brain, muscle tissues, and serum magnesium levels measured in all experimental groups and control 24 h later. Brain magnesium levels were found increased in all magnesium acetyl taurate administered subjects. Magnesium citrate increased muscle and brain magnesium levels in a dose-independent manner. We showed that dividing high doses of daily administered magnesium compounds did not sufficiently increase tissue magnesium levels. Although passive paracellular mechanism by solvent drag is the main mechanism of Mg absorption, other factors (electrochemical gradient effects, transcellular transporter mechanisms, magnesium status) should be effective on our results. It is necessary for further research on long-term administration of different magnesium compounds and their effect on other tissues.

Nicotine increased VEGF and MMP2 levels in the rat eye and kidney.

Chronic cigarette smoking affects many tissues negatively. Nicotine in tobacco has negative effects on tissues, kidneys, and eyes especially, where microcirculation is vitally important for the survival and functioning. It is known that appropriate vascular endothelial growth factor (VEGF) and (matrix metalloproteinase 2) MMP2 levels are required for suitable vascularity and enough microcirculation. The aim of this study was to investigate the effect of nicotine on VEGF and MMP2 levels in kidney and eyes, where microcirculation is very important for their function. The nicotine was given into drinking water, to male and female rats for 6 weeks. During the first 2 weeks, the nicotine concentration was 10 mg/L, then was given at a fixed dose of 20 mg/L until the end of the experiment. The VEGF and MMP2 levels were increased in kidney tissue of both genders as a result of given nicotine. MMP2 levels were also increased in the eye tissue for both genders similarly. However, VEGF levels increased in the eye tissue with nicotine in males, whereas it did not change in females. The use of nicotine made VEGF and MMP2 levels increase in kidney tissue in both genders of rats. This increase in VEGF was observed only in male eye tissue, not in females. According to our findings, it can be suggested that nicotine has negative effects on microvascular circulation by increasing VEGF and MMP2 levels. In addition, it should be pointed out that estrogen might have protective effects on female eye tissue. Further studies are necessary to understand the complex relationship between the role of nicotine and estrogen on eye and kidney tissues.

Anti-inflammatory and Anti-apoptotic Effect of Valproic Acid and Doxycycline Independent from MMP Inhibition in Early Radiation Damage.

BACKGROUND: Matrix metalloproteinase (MMP) inhibitors decrease inflammation in normal tissues and suppress cancer progress in normal tissues. Valproic acid (VA) and doxycycline (DX) are MMP inhibitors that have radio-protective effects. Their ability to inhibit MMPs in irradiated tissue is unknown and the role of MMPs in radio-protective effects has not been tested to date. AIMS: The purpose of this study was to examine whether administration of VA and DX to rats before irradiation affects tissue inflammation and apoptosis in the early phase of radiation, and whether the effect of these drugs is mediated by MMP inhibition. STUDY DESIGN: Animal experimentation. METHODS: Twenty-six Wistar rats were randomized into four groups: control (CTRL), radiation (RT), VA plus radiation (VA+RT), and DX plus radiation (DX+RT). Three study groups were exposed to a single dose of abdominal 10 Gy gamma radiation; the CTRL group received no radiation. Single doses of VA 300 mg/kg and DX 100 mg/kg were administered to each rat before radiation and all rats were sacrificed 8 hours after irradiation, at which point small intestine tissue samples were taken for analyses. Levels of inflammatory cytokines (TNF-α, IL-1ß, and IL-6) and matrix metal-loproteinases (MMP-2 and MMP 9) were measured by ELISA, MMP activities were measured by gelatin and casein zymography and apoptosis was assessed by terminal deoxynucleotidyl transferase dUTP nick end labeling assay. RESULTS: VA decreased the levels of TNF-α and IL-1ß proteins insignificantly and decreased apoptosis significantly in the irradiated tissue, but did not inhibit MMPs. In contrast, VA protected the basal MMP activities, which decreased in response to irradiation. No effect of DX was observed on the levels of inflammatory cytokines or activities of MMPs in the early phases of radiation apoptosis. CONCLUSION: Our findings indicated that VA protects against inflammation and apoptosis, and DX exhibits anti-apoptotic effects in early radiation and these effects are independent from MMP inhibition.

Mild-intensity Exercise Triggers VEGF in the Digestive Tract Via Both Hypoxic and Nonhypoxic Mechanisms

Abstract Hypoxia occurs in the splanchnic region during exercise associated with sympathetic activity. In the elderly, vascular insufficiency and low vascular endothelial growth factor (VEGF) expression are observed. Compared to young people, sympathetic signals of older individuals are blunted and more resistant to splanchnic blood flow alterations during exercise. VEGF induces vasodilation responses and hence may retain blood in the splanchnic vascular bed. We hypothesized that regular mild-intensity exercise triggers weak VEGF expression in the digestive tract of the elderly. The effects of exercise on the levels of VEGF, superoxide dismutase (SOD), glutathione peroxidase (GPx), malondialdehyde (MDA) and total antioxidant capacity (T-AOC) in the stomach, jejunum, ileum and colon tissues were evaluated. With exercise, the VEGF levels in the stomach and colon increased. Although the SOD, GPx, and MDA levels decreased in the stomach, they increased in the colon. T-AOC increased in the stomach and there was no change in the jejunum, ileum and colon. The hypoperfusion during exercise was not equal in all regions of the gastrointestinal tract in the aged subjects. Hypoxia and other exercise-related mechanisms could have led to this VEGF induction. The stomach, jejunum, and ileum might have developed resistance to ischemia. The induction of VEGF may be beneficial in aging-associated impaired gastrointestinal homeostasis and neovascularization.