The effects of Spirulina platensis on behavior in adolescent rats fed a high-fat diet

In recent years, childhood overweight and obesity have become a universal public health problem. Obesity may lead to cognitive disorders, depression and anxiety by affecting neuronal processes. Spirulina platensis (SP), a species of microalgae from the Chlorophyceae green algae class, has neuroprotective effects and may reduce body weight. In this study, we aimed to investigate the effects of SP on behavior alongside the role of leptin and Sirtuin-1 in fed with high-fat diet (HFD) adolescent rats. Four-week-old Sprague Dawley male rats were divided into four groups: control, HFD, HFD + SP150 (150 mg/kg/day SP, orally), HFD + SP450 (450 mg/kg/day SP, orally). Rats except for the control group exposed to 60% HFD along 12 weeks. Last 6 weeks SP or vehicle administered. After the behavioral tests, leptin and Sirtuin-1 levels in prefrontal cortex and hippocampus regions were evaluated. SP150 significantly reduced body weight compared with HFD group. The time spent in the center of open field increased significantly in SP150-treated rats compared with HFD. SP150 and SP450 significantly decreased immobility time in forced swim test compared with HFD. Leptin levels in HFD group were significantly lower in prefrontal cortex compared to control group. Leptin levels of the HFD + SP450 group were significantly higher than HFD group in the hippocampus. There was no significant difference between groups in Sirtuin-1 levels. In conclusion, SP supplementation in adolescence period might positively affect chronic high fat-induced anxiety-like and depressive-like behavior by partially affecting brain leptin levels and without affecting Sirtuin-1 levels.

The effects of bee venom on behavior and the role of leptin in rats

The aim of this study is to evaluate the dose‑dependent effect of bee venom (BV) on behavioral functions in rats and the physiological role of leptin in the prefrontal cortex, hippocampus, and amygdala tissues. Adult Sprague‑Dawley male rats were used in the experiments. The rats were divided into three groups of control, 0.1 mg/kg BV, and 0.5 mg/kg BV. The rats were injected with BV subcutaneously for 15 consecutive days. The open field test (OFT), the elevated plus maze test (EPM), and the forced swimming test (FST) were performed as behavioral assessments. Animals were sacrificed, and brain regions were removed. Leptin levels were measured in various brain regions by ELISA. In the OFT, the total distance and speed for the 0.1 mg/kg BV group increased compared to controls and the 0.5 mg/kg BV group. In the EPM, the 0.1 mg/kg BV group remained in the open arm for a significantly longer period of time compared to the other groups. In the FST, the 0.5 mg/kg BV group was more mobile than the other groups. Leptin levels in the prefrontal cortex were significantly higher in the 0.1 mg/kg BV group compared to the control and 0.5 mg/kg groups. There were no significant differences between groups in hippocampus and amygdala leptin levels. The results of the study show that BV has a positive effect on behavioral parameters. BV may have a positive effect on anxiety‑ and depression‑like behaviors by increasing leptin levels in the prefrontal cortex.

The effects of subtoxic dose of acetaminophen combined with exercise on the liver of rats

Regular physical exercise is beneficial to the body. Acute exercise causes oxidant stress in many tissues including the liver by creating an unbalanced status between oxidant and antioxidant levels. Analgesic drugs are commonly consumed to reduce the pain after exercise. Acetaminophen (APAP), commonly used as an over-the-counter analgesic, can cause hepatotoxicity. The aim of this study was to investigate the effect and underlying mechanisms of APAP at subtoxic dose, which is given after the acute and exhaustive exercise on the rat livers. Male Wistar rats weighing 200-250 g were divided into 6 groups each consisting of 7 rats/group; Control, APAP (250 mg/kg, ip), Acute Exercise (AEx), Acute Exhaustive Exercise (AEEx), Acute Exercise and APAP (AEx+APAP) and Acute Exhaustive Exercise and APAP (AEEx+APAP) groups. Rats were exercised at moderate intensity or exhaustive on the treadmill and then received APAP. Tissue MDA levels were significantly increased in AEEx, AEx+APAP and AEEx+APAP groups compared with the control. There was no significant difference in GSH levels between groups. Tissue Sirtuin1 (Sirt1) levels of APAP, AEx and AEEx groups were significantly less than control. There was no significant difference between groups in VEGF levels. Liver damage score was significantly higher in all groups compared with control group. As a result, this study shows that subtoxic dose of APAP treatment alone or in combination with acute or exhaustive treadmill exercise can cause oxidative liver damage by affecting Sirt1 levels and without affecting VEGF levels.

The Effects of Prenatal and Postnatal Exposure to 50-Hz and 3 mT Electromagnetic Field on Rat Testicular Development

Background and objectives: It has been shown that electromagnetic fields (EMFs) have negative effects on the reproductive system. The biological effects of EMF on the male reproductive system are controversial and vary depending on the frequency and exposure time. Although a limited number of studies have focused on the structural and functional effects of EMF, the effects of prenatal and postnatal EMF exposure on testes are not clear. We aimed to investigate the effects of 50-Hz, 3-mT EMF exposure (5 days/wk, 4 h/day) during pre- and postnatal periods on testis development. Materials and Methods: Pups from three groups of Sprague-Dawley pregnant rats were used: Sham, EMF-28 (EMF-exposure applied during pregnancy and until postnatal day 28), EMF-42 (EMF-exposure applied during pregnancy and until postnatal day 42). The testis tissues and blood samples of male offspring were collected on the postnatal day 42. Results: Morphometric analyses showed a decrease in seminiferous tubule diameter as a result of testicular degeneration in the EMF-42 group. Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels were decreased in the EMF-42 group. Lipid peroxidation levels were increased in both EMF groups, while antioxidant levels were decreased only in the EMF-28 group. We found decreased levels of vascular endothelial growth factor (VEGF) and insulin-like growth factor-1 (IGF1) in the EMF-42 group, and decreased levels of the SRC homology 3 (SH3) and multiple ankyrin repeat domain (SHANK3) in the EMF-28 group in the testis tissue. Conclusions: EMF exposure during pre- and postnatal periods may cause deterioration in the structure and function of testis and decrease in growing factors that would affect testicular functions in male rat pups. In addition to the oxidative stress observed in testis, decreased SHANK3, VEGF, and IGF1 protein levels suggests that these proteins may be mediators in testis affected by EMF exposure. This study shows that EMF exposure during embryonic development and adolescence can cause apoptosis and structural changes in the testis.

The effects of bee venom on liver and skeletal muscle in exhaustive swimming rats

Oxidative damage and proinflammatory cytokines are involved in exhaustive exercise-induced fatigue. This study aimed to investigate the effects of bee venom, a natural toxin, on fatigue and tissue damage in rats that underwent forced swimming exercise. Rats were divided into four groups: control, swimming exercise (SE), bee venom (BV) and swimming exercise + bee venom (SE + BV). SE and SE + BV groups were subjected to forced swimming (load of 7% body weight) for 5 days. BV and SE + BV groups were injected with 1 mg/kg BV subcutaneously. Swimming time, blood lactate and TNF-α levels, MDA and GSH levels in liver and gastrocnemius muscle were evaluated. Swimming time was shorter in SE + BV group than SE group. There was no difference in lactate levels between SE and SE + BV groups. MDA and GSH levels were increased in SE, BV and SE + BV groups. TNF-α levels were increased in BV group compared to control and SE groups. Our study demonstrated that BV administration before exhaustive exercise in rats did not provide anti-fatigue effect. Additionally, BV did not show anti-inflammatory activity and had different effects on antioxidant capacity at tissue level. Further research might explore the effects of different doses and durations of BV on exhaustive exercise.

Dose dependent effects of oxytocin on cognitive defects and anxiety disorders in adult rats following acute infantile maternal deprivation stress

Maternal deprivation at an early age is a powerful stressor that causes permanent alterations in cognitive and behavioral functions during the later stages of life. We investigated the effects of oxytocin on cognitive defects and anxiety disorders caused by acute infantile maternal deprivation in adult rats. We used 18-day-old Wistar albino rats of both sexes. The experimental groups included control (C), maternally deprived (MD), maternally deprived and treated with 0.02 μg/kg oxytocin (MD-0.02 µg/kg oxy), maternally deprived and treated with 2 μg/kg oxytocin (MD-2 µg/kg oxy). When the rats were 60 days old, the open field (OF) and elevated plus maze (EPM) behavioral tests, and the Morris water maze (MWM) test for spatial learning and memory were performed. In addition, the number of neurons in the hippocampus, prefrontal cortex (PFC) and amygdala were determined using quantitative histology. We also measured vascular endothelial growth factor (VEGF) and brain-derived neurotrophic factor (BDNF) levels in the PFC. In both sexes, the MD group failed the learning test and the MD-2 μg/kg oxy group failed in the memory test. The MD-0.02 μg/kg oxy group spent more time in the open arm of the EPM device and their locomotor activities were greater in the OF test. The VEGF and BDNF levels in the PFC were higher in the MD-0.02 μg/kg oxy groups than the other maternally deprived groups (oxytocin ±). The number of PFC neurons was low in all male maternally deprived (oxytocin ±) groups, while the number of amygdala neurons was low in both female and male maternally deprived (oxytocin ±) groups. Male rats were more affected by maternal deprivation; administration of oxytocin had dose-dependent biphasic effects on learning, memory and anxiety.

Erythropoietin diminishes isoflurane-induced apoptosis in rat frontal cortex

BACKGROUND

During the brain growth spurt, anesthetic drugs can cause cellular and behavioral changes in the developing brain. The aim of this study was to determine the neuroprotective effect of erythropoietin after isoflurane anesthesia in rat pups.

METHODS

A total of 42, 7-day-old Wistar rats were divided into three groups. Control group (GC; n = 14): Rats breathed 100% oxygen for 6 h; Isoflurane group (GI; n = 14): Rats were exposed to 1.5% isoflurane in 100% oxygen for 6 h; Isoflurane + erythropoietin group (GIE; n = 14): 1000 IU·kg(-1) (intraperitoneal; IP) Erythropoietin was administered after isoflurane anesthesia. Each group was divided into two groups for pathology and learning and memory tests. Silver, caspase-3, and fluoro-jade C staining were used for detecting apoptotic cells in frontal cortex, striatum, hippocampus, thalamus, and amygdala. Morris water maze was used to evaluate learning and memory.

RESULTS

There was a significant increase in apoptotic cell count after isoflurane anesthesia in the frontal cortex when compared with control group (29.0 ± 9.27 vs 3.28 ± 0.75 [P = 0.002], 20.85 ± 10.94 vs 2.0 ± 0.81 [P = 0.002] and 24.57 ± 10.4 vs 5.14 ± 0.69 [P = 0.024] with silver, caspase-3, and fluoro-jade C staining, respectively). The apoptotic cell count in the frontal cortex was significantly higher in GIE than GC with caspase-3 staining (9.14 ± 3.13 vs 2.0 ± 0.81, P = 0.002). The apoptotic cell count in GIE was significantly reduced in the frontal cortex when compared with GI (4.0 ± 0.81 vs 29.0 ± 9.27 [P = 0.002], 9.14 ± 3.13 vs 20.85 ± 10.94 [P = 0.04] and 4.0 ± 1.63 vs 24.57 ± 10.4 [P = 0.012] with silver, caspase-3, and fluoro-jade C staining, respectively).

CONCLUSIONS

A total of 1000 IU·kg(-1) IP erythropoietin diminished isoflurane-induced neuroapoptosis. Further experimental studies have to be planned to reveal the optimal dose and timing of erythropoietin before adaptation to clinical practice.

The effects of oxytocin on cognitive defect caused by chronic restraint stress applied to adolescent rats and on hippocampal VEGF and BDNF levels

Background

Because brain development continues during adolescence, the effects of chronic stress on hippocampal changes that occur during that period are permanent. Oxytocin, which is synthesized in the hypothalamus and has many receptors in brain regions, including the hippocampus, may affect learning-memory. This study aimed to investigate chronic restraint stress on hippocampal functions, and hippocampal vascular endothelial growth factor (VEGF) and brain-derived neurotrophic factor (BDNF) levels in adolescent male and female rats and the role of oxytocin in these effects.

Material/Methods

Experimental groups included control, stress+oxytocin, and stress+saline groups. Restraint stress was applied to all the stress groups for 1 h/day, for 7 days. Learning-memory tests were performed after the 7^th day.

Results

In the stress+oxytocin groups, the process of finding the platform was shorter than in others groups. The stress+saline groups spent less time, whereas the stress+oxytocin groups spent more time, on the target quadrant in the probe trial. In the stress+oxytocin groups thigmotaxis time (indicating anxiety) decreased, but VEGF and BDNF levels increased. A positive correlation was found between VEGF and BDNF levels and the time spent within the target quadrant.

Conclusions

The results indicate that impaired hippocampal learning and memory loss due to chronic restraint stress can be positively affected by intranasal oxytocin.

Effects of voluntary and involuntary exercise on cognitive functions, and VEGF and BDNF levels in adolescent rats

Regular treadmill running during adolescence improves learning and memory in rats. During adolescence, the baseline level of stress is thought to be greater than during other periods of life. We investigated the effects of voluntary and involuntary exercise on the prefrontal cortex and hippocampus, vascular endothelial growth factor (VEGF), brain-derived neurotrophic factor (BDNF) levels, and spatial learning, memory and anxiety in adolescent male and female rats. The voluntary exercise group was given free access to a running wheel for 6 weeks. The involuntary exercise group was forced to run on a treadmill for 30 min at 8 m/min 5 days/week for 6 weeks. Improved learning was demonstrated in both exercise groups compared to controls. Neuron density in the CA1 region of the hippocampus, dentate gyrus and prefrontal cortex were increased. Hippocampal VEGF and BDNF levels were increased in both exercise groups compared to controls. In females, anxiety and corticosterone levels were decreased; BDNF and VEGF levels were higher in the voluntary exercise group than in the involuntary exercise group. The adolescent hippocampus is affected favorably by regular exercise. Although no difference was found in anxiety levels as a result of involuntary exercise in males, females showed increased anxiety levels, and decreased VEGF and BDNF levels in the prefrontal cortex after involuntary exercise.

Combined treatment with progesterone and magnesium sulfate positively affects traumatic brain injury in immature rats

AIM

It is well known that head trauma results in damage in hippocampal and cortical areas of the brain and impairs cognitive functions. The aim of this study is to explore the neuroprotective effect of combination therapy with magnesium sulphate (MgSO4) and progesterone in the 7-days-old rat pups subjected to contusion injury.

MATERIAL AND METHODS

Progesterone (8 mg/kg) and MgSO4 (150 mg/kg) were injected intraperitoneally immediately after induction of traumatic brain injury. Half of groups were evaluated 24 hours later, the remaining animals 3 weeks after trauma or sham surgery. Anxiety levels were assessed with open field activity and elevated plus maze; learning and memory performance were evaluated with Morris Water maze in postnatal 27 days.

RESULTS

Combined therapy with progesterone and magnesium sulfate significantly attenuated trauma-induced neuronal death, increased brain VEGF levels and improved spatial memory deficits that appear later in life. Brain VEGF levels were higher in rats that received combined therapy compared to rats that received either medication alone. Moreover, rats that received combined therapy had reduced hipocampus and prefrontal cortex apoptosis in the acute period.

CONCLUSION

These results demonstrate that combination of drugs with different mechanisms of action may be preferred in the treatment of head trauma.

Effects of administration of subtoxic doses of acetaminophen on liver and blood levels of insulin-like growth factor-1 in rats

Acetaminophen (APAP) is widely used in the treatment of pain. Toxic doses of APAP cause acute liver failure, but therapeutic doses are believed to be safe. The purpose of this study is to investigate the effects of administration of subtoxic doses of APAP on liver and blood levels of insulin-like growth factor-1 (IGF-1) in rats. Low dose (100 mg/kg) and high dose (250 mg/kg) of APAP were intraperitoneally injected into Wistar albino rats. Following administration of therapeutic doses of APAP, there were no significant changes in serum transaminases and liver glutathione levels. Both doses of APAP induced a decrease in liver and blood levels of IGF-1 when compared with the controls. There was no significant difference in liver IGF-1 levels between the high-dose and low-dose APAP groups; however, there was a significant difference in blood IGF-1 levels between both the groups. The histological examination showed that low dose of APAP induced mild degree of structural change, while high dose of APAP induced severe structural damage. In conclusion, these results suggest that blood IGF-1 levels may have a value in predicting hepatic damage resulting from therapeutic doses of APAP.

Positive effects of aerobic exercise on learning and memory functioning, which correlate with hippocampal IGF-1 increase in adolescent rats

It is already known that regular aerobic exercise during adolescent period improves learning and memory in rats. In this study, we investigated the effects of regular aerobic exercise on learning, memory functioning and IGF-1 levels. IGF-1 is known to have positive effects on cognitive functions in adolescent rats. Exercise group was separated into two different groups. First half was run on a treadmill for 30 min per session at a speed of 8m/min and 0° slope, five times a week for 6 weeks. The second half was given free access to a running wheel (diameter 11.5 cm) which was connected to a digital counter and run on a treadmill for 6 weeks. Learning and memory functioning were found to be positively correlated with the exercise activity. Findings suggest increased neuron density in CA1 hippocampal region and dentate gyrus. Increased IGF-1 level was detected in hippocampus and blood serum, while IGF-1 level in liver tissue did not change with exercise activity. In conclusion, our findings indicate that learning and memory functioning were positively affected by voluntary and involuntary physical exercise which correlated increased hippocampal activity and elevated IGF-1 levels in adolescent rats.

Serum IGF-1 levels correlate negatively to liver damage in diabetic rats

Diabetes and insulin resistance frequently cause liver damage. Diabetes also causes reduction in liver and blood IGF-1 levels. We investigated the relation between liver damage and IGF-1 levels in diabetic rats. Fourteen Wistar albino rats were divided into control and diabetic groups. Diabetes was induced by streptozotocin. Rats were sacrificed for biochemical and histologic examinations 2 weeks after streptozotocin injection. Serum and liver IGF-1 levels were decreased, liver malondialdehyde (MDA) levels were increased, glutathione peroxidase (GPx) enzymes activities were decreased and serum alanine aminotransferase (ALT) levels were increased in diabetic group. Microscopic examination of liver revealed that normal tissue organization was disrupted in streptozotocin-induced diabetic rats. There was a strongly positive correlation between blood glucose levels and liver injury, and blood and liver IGF-1 levels. There was a strongly negative correlation between blood IGF-1 levels and hepatic injury. Our results suggest that reduction of blood IGF-1 levels correlates with hepatic injury and circulating IGF-1 levels may have predictive value for determining hepatic damage that results from diabetes. In addition, circulating IGF-1 levels are correlated with glutathione levels and the oxidative stress status of diabetic rat liver.

Anxiety correlates to decreased blood and prefrontal cortex IGF-1 levels in streptozotocin induced diabetes

It is well known that diabetes mellitus may cause neuropsychiatric disorders such as anxiety disorders. Diabetes may also cause reduced IGF-1 (insulin like growth factor-1) levels in brain and blood. The purpose of the present study was to investigate the relationship between diabetes induced anxiety and IGF-1 levels in diabetic rats. The anxiety levels of rats were assessed 2 weeks after intraperitoneal injection of streptozotocin. Diabetic rats had higher levels of anxiety, as they spent more time in closed branches in elevated-plus-maze-test and less time in the center cells of open-field-arena. Prefrontal cortex (PFC) IGF-1 levels and neuron numbers were decreased and apoptosis was increased in diabetic rats. Blood IGF-1 levels decreased in a time dependent fashion following streptozotocin injection while blood corticosterone levels increased. They had higher malondialdehyde levels and lower superoxide dismutase enzyme activity. Oxidative stress may negatively affect blood and PFC tissue IGF-1 levels. Reduction in IGF-1 may cause PFC damage, which may eventually trigger anxiety in diabetic rats. Therapeutic strategies that increase blood and brain tissue IGF-1 levels may be promising to prevent psychiatric sequelae of diabetes mellitus.

Maternal aerobic exercise during pregnancy can increase spatial learning by affecting leptin expression on offspring's early and late period in life depending on gender

Maternal exercise during pregnancy has been suggested to exert beneficial effects on brain functions of the offspring. Leptin is an adipocytokine which is secreted from adipose tissues and has positive effects on learning, memory, and synaptic plasticity. In this study, pregnant rats were moderately exercised and we observed the effects of this aerobic exercise on their prepubertal and adult offsprings' spatial learning, hippocampal neurogenesis, and expression of leptin. All the pups whose mothers exercised during pregnancy learned the platform earlier and spent longer time in the target quadrant. Their thigmotaxis times were shorter than those measured in the control group. It is shown that hippocampal CA1, CA3 neuron numbers increased in both prepubertal and adult pups, in addition that GD neuron numbers increased in adult pups. Leptin receptor expression significantly increased in the prepubertal male, adult male, and adult female pups. In our study, maternal running during pregnancy resulted in significant increase in the expression of leptin receptor but not in prepubertal female pups, enhanced hippocampal cell survival, and improved learning memory capability in prepubertal and adult rat pups, as compared to the control group. In conclusion, maternal exercise during pregnancy may regulate spatial plasticity in the hippocampus of the offspring by increasing the expression of leptin.

Maternal treadmill exercise during pregnancy decreases anxiety and increases prefrontal cortex VEGF and BDNF levels of rat pups in early and late periods of life

In a previous study we demonstrated that, regular aerobic exercise during pregnancy decreased maternal deprivation induced anxiety. The purpose of this study is to investigate whether the positive effects of maternal exercise on the male and female offspring's early and late period of life. Half of the test subjects in each group were evaluated when they were 26 days old, and the other half were evaluated when they were 4 months old. The anxiety levels of maternally exercised groups were less than the control groups in both sexes and in both prepubertal and adult periods. The locomotor activity more increased in females. The prefrontal VEGF and BDNF levels were greater for both age groups and sexes in the maternally exercised group compared to control group. Moreover, there was a strong positive correlations between prefrontal cortex BDNF levels and results of open field tests; and VEGF levels and results of elevated plus maze tests. There was no difference in serum corticosterone levels between groups. These results indicate that maternal exercise during pregnancy may protect the pups from anxiety in early and late periods of life, and affects the prefrontal cortex positively.

Relationship between circulating IGF-1 levels and traumatic brain injury-induced hippocampal damage and cognitive dysfunction in immature rats

It is well known that traumatic brain injury (TBI) induces the cognitive dysfunction resulting from hippocampal damage. In the present study, we aimed to assess whether the circulating IGF-I levels are associated with cognition and hippocampal damage in 7-day-old rat pups subjected to contusion injury. Hippocampal damage was examined by cresyl violet staining and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. Spatial memory performance was assessed in the Morris water maze. Serum IGF-1 levels decreased in both early and late period of TBI. Decreased levels of serum IGF-1 were correlated with hippocampal neuron loss and spatial memory deficits. Circulating IGF-1 levels may be predictive of cognitive dysfunction resulted from hippocampal damage following traumatic injury in developing brain. Therapy strategies that increase circulating IGF-1 may be highly promising for preventing the unfavorable outcomes of traumatic damage in young children.

Maternal exercise decreases maternal deprivation induced anxiety of pups and correlates to increased prefrontal cortex BDNF and VEGF

Maternal deprivation (MD) may cause neuropsychiatric disorders such as anxiety disorder by negatively affecting the cognitive functions and behavior in pups. The aim of this study is to investigate whether maternal exercise during pregnancy has beneficial effects on anxiety that increases with MD, and on the levels of VEGF and BDNF which have anxiolytic effects on the prefrontal cortex, the anxiety-related region of the brain. The anxiety level in the deprivation group was greater than the control group and found more in male than female pups. The prefrontal cortex VEGF and BDNF levels were decreased in the deprivation group compared to control group while serum corticosterone levels were increased in the deprivation group. Anxiety and serum corticosterone levels were decreased in maternally exercised female and male pups, while the prefrontal cortex VEGF and BDNF levels were increased, compared to sedentary mother's pups. These results indicate that maternal exercise may attenuate the negative effect of stresses such as maternal deprivation that can be encountered early in life.

The effect of the acute submaximal exercise on thrombin activatable fibrinolysis inhibitor levels in young sedentary males

Depending on type, duration, and intensity of the exercise, changes occur in hemostasis. In this study, we evaluated the changes in the parameters of coagulation and fibrinolytic systems that happened after the submaximal aerobic exercises by bicycle ergomater. Twelve healthy male participants whose ages were between 21 and 28 have been included. The venous samples have been drawn before the exercise as well as at the 0 th, 15th, and 60th minutes after the submaximal exercise. The values of prothrombin time (PT), active partial thromboplastin time (aPTT), D-dimer, fibrinogen, plasminogen activator inhibitor 1 (PAI-1) and thrombin-activatable fibrinolysis inhibitor (TAFI) have been measured. Plasminogen activator inhibitor 1 values have shown an insignificant increase after exercise (P = .328), whereas, it has decreased significantly during the resting period (P = .033) Postexercise 15th and 60th minutes TAFI values have decreased significantly comparing to basal and postexercise (0 th minute) values (P = .001). Fibrinolytic system activation is observed after acute submaximal aerobic exercise of sedentary healthy participants.

Protective effects of methylxanthines on hypoxia-induced apoptotic neurodegeneration and long-term cognitive functions in the developing rat brain

Aminophylline is widely used in the management of premature apnea. The methylxanthines aminophylline, theophylline and caffeine are nonspecific inhibitors of adenosine receptors. There are no proven effects of methylxanthines on acute brain injury and long-term cognitive functions. This study is aimed at investigating the effects of methylxanthines on brain injury and cognitive functions. Newborn rats were allocated to form four groups, which contained at least 21 pups: two groups were exposed to room air and two groups were exposed to intermittent hypoxia. Intraperitoneal aminophylline was administered to treatment groups during postnatal day 1 through postnatal day 7. All rats were sacrificed on postnatal day 8 via intraperitoneal pentobarbital and the effects of the administered drug on brain injury and adenosine receptor expression were determined. Cognitive functions of rats were evaluated via water maze test. Histopathological evaluation demonstrated that aminophylline significantly diminished the number of 'apoptotic cells' in the hippocampal CA1, CA2, CA3 and gyrus dentatus regions in the brain. Aminophylline treatment immediately after hypoxic insult significantly improved long-term neurobehavioral achievements. In conclusion, aminophylline administration immediately after neonatal hypoxic insult provides benefit over a prolonged period in the developing rat brain.

Suppression of apoptosis and oxidative stress by deprenyl and estradiol in aged rat liver

Aging is accompanied by significant structural and functional transformations of all organs and systems. Age-associated increase in apoptotic behavior may cause disease. Older cells are more susceptible to endogenous oxidative damage, and oxidative stress is a potent inducer of apoptosis. Deprenyl is an irreversible monoamine-oxidase B inhibitor which has anti-oxidant, anti-apoptotic and neuroprotective effects. Estrogen is also a neuroprotective and anti-oxidant hormone. The objectives of this study were to determine whether the anti-oxidative effects of deprenyl can suppress apoptotic activity, with or without estradiol, in aged female rat livers. In this study, ovariectomized female Wistar albino rats were divided into six groups as follows; young (3 months old) saline-treated control, aged (24 months old) saline-treated control, aged deprenyl treated, aged estradiol treated, aged deprenyl plus estradiol treated and aged sham controls. All rats except for the sham group were treated for 21 days. Determination of oxidative stress parameters was performed spectrophotometrically. To detect apoptotic cells, TUNEL staining was performed. The results were analyzed by one-way ANOVA post hoc Bonferroni test. Deprenyl and estradiol administration, alone or in combination, decreased significantly the levels of lipid peroxidation and increased superoxide dismutase activity in the liver relative to aged control and sham rats (P<0.05). The number of TUNEL positive cells decreased significantly in deprenyl and estradiol-treated rats compared with aged control and sham rats. The results indicate that deprenyl treatment alone, or in combination with estradiol, may modulate age-related apoptotic changes in rat liver by decreasing oxidative stress.

The effect of melatonin on endotoxemia-induced intestinal apoptosis and oxidative stress in infant rats

OBJECTIVE

To evaluate the effect of melatonin on the intestinal apoptosis along with oxidative damage in endotoxemic infant rats.

DESIGN AND SETTING

Prospective animal study in a university-based experimental research laboratory.

SUBJECTS AND INTERVENTIONS

Wistar albino 7-day-old rat pups (n=21). The animals were randomized into three experimental groups: (1) controls; (2) endotoxemia; (3) endotoxemia treated with melatonin (10mg/kg). Endotoxemia was induced in rats by intraperitoneal injection of lipopolysaccharide (Escherichia coli serotype 0111:B4; 3 mg/kg).

MEASUREMENTS AND RESULTS

Four hours after LPS injection, the antioxidant enzyme activities, including superoxide dismutase (SOD), glutathione peroxidase (GPx), and thiobarbituric acid reactive substance (TBARS) levels as an indicator of lipid peroxidation, were determined. Intestinal apoptosis was assessed by hematoxylin-eosin staining and terminal deoxynucleotide transferase-mediated fluorescein-dUTP nick end labeling. The administration of melatonin into endotoxemic rats prevented the increase in the TBARS levels, and increased the activities of antioxidant enzymes and attenuated apoptotic cell death in both intestinal epithelium and lamina propria.

CONCLUSIONS

Melatonin diminished the intestinal oxidative stress and apoptotic damage induced by endotoxemia in infant rats.

Acute exhaustive exercise does not alter lipid peroxidation levels and antioxidant enzyme activities in rat hippocampus, prefrontal cortex and striatum

Although regular physical exercise is beneficial to the body, it is well known that exhaustive exercise causes oxidative stress in muscle. Recent studies suggest that regular moderate physical exercise has the beneficial effects on brain. However, there is little information regarding whether or not exhaustive exercise could generate oxidative stress in brain and the findings are conflicting. The aim of this study was to investigate the effects of exhaustive exercise on thiobarbituric acid reactive substances, as an indicator of lipid peroxidation, in the hippocampus, prefrontal cortex and striatum. Additionally we examined antioxidant enzymes activities, superoxide dismutase and glutathione peroxidase, to assess the effects of reactive oxygen species. Exhaustive exercise did not change superoxide dismutase and glutathione peroxidase enzyme activities and thiobarbituric acid reactive substances levels neither immediately (0 min) nor at 3, 6, 12, 24 and 48 h after the cessation of exercise in the brain. These results indicate that acute exhaustive exercise may not cause significant lipid peroxidation in the hippocampus, prefrontal cortex and striatum during the post-exercise period.

The effects of regular aerobic exercise in adolescent period on hippocampal neuron density, apoptosis and spatial memory

It is known that positive effects of regular aerobic exercise on cognitive functions in humans and also animals; but how to the effects of aerobic exercise in adolescent period is unknown. The present study examined the effects of regular aerobic exercise on spatial memory using the Morris water maze, cell density and apoptosis of hippocampus in adolescent rats. Twenty-two days of age male rats were run on a treadmill for 30 min/session at a speed of 8m/min and 0 degrees slope, five times a week for 8 weeks. The present study showed that exercise induced significant cognitive improvement throughout brain maturation in rats. The number of hippocampal CA1 and CA3 neurons, and gyrus dentatus neurons were significantly increased in the exercised rats. There was no significant difference of CA2 neuron density between exercise and control groups. There was no significantly differences in any groups according to the results of apoptosis that account of TUNEL positive cells. The present results suggest that regular moderate aerobic treadmill exercise benefit in cognitive functions. This result may derive from treadmill exercise-induced increase cell density without altering of apoptosis in the hippocampus and dentate gyrus of adolescent rats.

Effects of melatonin on oxidative stress and spatial memory impairment induced by acute ethanol treatment in rats

Melatonin has recently been suggested as an antioxidant that may protect neurons from oxidative stress. Acute ethanol administration produces both lipid peroxidation as an indicator of oxidative stress in the brain and impairs water-maze performance in spatial learning and memory tasks. The present study investigated the effect of melatonin against ethanol-induced oxidative stress and spatial memory impairment. The Morris water maze was used to evaluate the cognitive functions of rats. Thiobarbituric acid reactive substances (TBARS), which are the indicators of lipid peroxidation, and the activities of antioxidative enzymes (glutathione peroxidase and superoxide dismutase) were measured in the rat hippocampus and prefrontal cortex which form interconnected neural circuits for spatial memory. Acute administration of ethanol significantly increased TBARS levels in the hippocampus. Combined melatonin-ethanol treatment caused a significant increase in glutathione peroxidase activities and a significant decrease of TBARS in the rat hippocampus. In the prefrontal cortex, there was only a significant decrease of TBARS levels in the combined melatonin-ethanol receiving group as compared to the ethanol-treated group. Melatonin did not affect the impairment of spatial memory due to acute ethanol exposure, but melatonin alone had a positive effect on water maze performances. Our study demonstrated that melatonin decreased ethanol-induced lipid peroxidation and increased glutathione peroxidase activity in the rat hippocampus.

Effects of melatonin on oxidative stress and spatial memory impairment induced by acute ethanol treatment in rats

Melatonin has recently been suggested as an antioxidant that may protect neurons from oxidative stress. Acute ethanol administration produces both lipid peroxidation as an indicator of oxidative stress in the brain and impairs water-maze performance in spatial learning and memory tasks. The present study investigated the effect of melatonin against ethanol-induced oxidative stress and spatial memory impairment. The Morris water maze was used to evaluate the cognitive functions of rats. Thiobarbituric acid reactive substances (TBARS), which are the indicators of lipid peroxidation, and the activities of antioxidative enzymes (glutathione peroxidase and superoxide dismutase) were measured in the rat hippocampus and prefrontal cortex which form interconnected neural circuits for spatial memory. Acute administration of ethanol significantly increased TBARS levels in the hippocampus. Combined melatonin-ethanol treatment caused a significant increase in glutathione peroxidase activities and a significant decrease of TBARS in the rat hippocampus. In the prefrontal cortex, there was only a significant decrease of TBARS levels in the combined melatonin-ethanol receiving group as compared to the ethanol-treated group. Melatonin did not affect the impairment of spatial memory due to acute ethanol exposure, but melatonin alone had a positive effect on water maze performances. Our study demonstrated that melatonin decreased ethanol-induced lipid peroxidation and increased glutathione peroxidase activity in the rat hippocampus.