Adenosine protects D-galactose induced alterations in rat model of aging via attenuating neurochemical profile and redox status

Aging is the process that every organism faces. The aging model of brain has been developed by the use of d-galactose (d-Gal). Adenosine (Ad) being a neuroprotective agent that has been utilized in treatment of various neurological disorders. The aim of current study is to evaluate the outcome of Ad on d-Gal induced neurotoxicity which caused behavioral deficits, memory impairment and oxidative stress. Rats were treated with d-Gal at a dose of 300 mg/ml/kg and Ad 1 mg/ml/kg; intraperitoneally for 28 days. Behavioral assessment was performed after the treatment period. Animals were sacrificed after behavioral tests and their brains were collected, hippocampus were removed for biochemical and neurochemical analysis. The results showed that administration of Ad ameliorates the negative effects of d-Gal induced aging in various behavioral tests and increased the time spent in the open arm and light box in elevated plus maze (EPM) and light dark activity (LDA) tests respectively indicate anxiolytic effect; increased the mobility time in tail suspension test (TST) shows antidepressant effect; decreased escape latencies in Morris water maze (MWM) acquisition trials, increase entries and time spent in the target quadrant suggests improvement in learning ability of animals. Administration of Ad also decreased malondialdehyde (MDA) levels, increased antioxidant enzymes activity; decreased acetylcholinesterase (AChE) activity, increased 5-hydroxytryptamine (5-HT, serotonin) metabolism and normalized histopathological alteration in the hippocampus. It is concluded that anxiety, depression and memory impairment induced by d-Gal were protected by Ad through its antioxidant and neuro-modulatory effects.

Artemisia argyi exhibits anti-aging effects through decreasing the senescence in aging stem cells

Aging is accompanied by functional loss of many cellular pathways, creating an increased risk of many age-related complications (ARC). Aging causes stem cell exhaustion with a concomitant increase in cellular dysfunction. Recently, interest in senotherapeutics has been growing rapidly to promote healthy aging and as an intervention for ARCs. This research focused on screening the senomorphic properties of Artemisia argyi, as an emerging strategy for longevity, and prevention or treatment of ARCs. In this study, we aimed to find the clinical efficacy of daily consumption of Artemisia argyi water extract (AAW) on aging. In vitro 0.1μM Doxorubicin induced senescent human adipose derived mesenchymal stem cells was treated with different concentrations of AAW to show its anti-aging effect. 15 months old SHR rats (n=6) were treated with 7.9 mg/ml AAW for 4 weeks and anti-aging effect was evaluated. In vitro study showed the protective effect of AAW in telomere shortening and helps in maintaining a balance in the expression of anti-aging protein Klotho and TERT. AAW effectively reduced mitochondrial superoxide and also provided a protective shield against senescence markers like over-expression of p21 and formation of double strand breaks, which is known to cause premature aging. Moreover, animal studies indicated that AAW promoted the expression of Klotho in naturally aging rats. In addition, AAW successfully restored the decline cardiac function and improved the grip strength and memory of aging rat. These findings showed that therapeutic targeting of senescent stem cells by AAW restored stem cell homeostasis and improves overall health.

D-galactose induced dysfunction in mice hippocampus and the possible antioxidant and neuromodulatory effects of selenium

Aging is an ultimate reality that everyone has to face. D-galactose (D-gal) has been used extensively to develop aging model. Trace elements such as selenium (Se) have been used as a potential antioxidant for neuro-protection. The present work aims to develop therapeutic agents such as Se for the treatment of aging-induced neurological ailments such as anxiety, depression, and memory impairment. For this purpose, mice were treated with D-gal at a dose of 300 mg/ml/kg and various doses of Se (0.175 and 0.35mg/ml/kg) for 28 days. Behavioral tests were monitored after treatment days. After the behavioral assessment, mice were decapitated and their brains were collected. Hippocampi were removed from the brain for biochemical, neurochemical, and histopathological analysis. The present findings of behavioral analysis showed that D-gal-induced anxiety- and depression-like symptoms were inhibited by both doses of Se. D-gal-induced memory alteration was also prevented by repeated doses of Se (0.175 and 0.35mg/ml/kg). Biochemical analysis showed that D-gal-induced increase of oxidative stress and inflammatory markers and decrease of antioxidant enzymes and total protein contents in the hippocampus were prevented by Se administration. An increase in the activity of acetylcholinesterase was also diminished by Se. The neurochemical assessment showed that D-gal-induced increased serotonin metabolism and decreased acetylcholine levels in the hippocampus were restored by repeated treatment of Se. Histopathological estimations also exhibited; normalization of D-gal induced neurodegenerative changes. It is concluded that D-gal-induced dysfunction in mice hippocampus caused anxiety, depression, memory impairment, oxidative stress, neuro-inflammation, and histological alterations that were mitigated by Se via its antioxidant potential, anti-inflammatory property, and modulating capability of serotonergic and cholinergic functions.

The protective effect of Indian Catechu methanolic extract against aluminum chloride-induced neurotoxicity, A rodent model of Alzheimer's disease

Alzheimer's disease (AD) is the commonest neurodegenerative disorder with a wide array of manifestations, courses, and contributing causes. Despite being clinically characterized a long time ago; no treatment has been developed that could improve the pathology or slow down the disease manifestation- so far. Indian Catechu methanolic extract (ICME) has proved to have multiple beneficial effects that support its use in several disorders- especially those with complex etiology. In the present study, we evaluated the neuroprotective effect of ICME in a rat model of AD using Aluminum Chloride (AlCl3). The results showed that ICME could have a positive impact on the course of AD through its anticholinesterase effect and significant antioxidant effect which was reflected on the animals both on behavioral tests as well as hallmark pathological findings.

Protective effect of gallic acid against arsenic-induced anxiety-/depression- like behaviors and memory impairment in male rats

The purpose of the present study is to determine the effects of gallic acid (GA) on sodium arsenite (iAS)-induced behavior deficits and memory alteration in male rats. Thirty six animals were divided in to 6 groups (six animals in each) (i) saline+saline; (ii) saline+GA (50 mg/kg); (iii) saline+ GA (100 mg/kg) (iv) iAS + saline; (v) iAS + GA(50 mg/kg); (vi) iAS + GA (100 mg/kg). Animals were treated with iAS (2.5 mg/kg/ml); GA (50 and 100 mg/kg/ml) and saline (0.9%; 1 ml/kg) for 4 weeks. Repeated administration of iAS increases immobility time in forced swim test and decreases time spent in open arm (elevated plus maze) and light box (light dark activity box test) suggests depression like and anxiety-like symptoms respectively. On the other hand, animals treated with iAS + GA decreases immobility time and increases time spent in open arm and light box than saline+iAS treated animals suggests anxiolytic and antidepressant-like behavior of GA. Repeated administration of iAS also involves in memory impairment as observed in the Morris water maze test that is reversed by co-administration of GA, indicates that GA also involves in the enhancement of memory. Brain malondialdehyde (MDA) levels, antioxidant enzymes and acetylcholinesterase (AChE) activities also observed in the present study. Results show that iAS produces oxidative stress by increasing lipid peroxidation and decreasing antioxidant enzyme activity. Conversely co-administration of GA produces antioxidant effects by normalization of oxidative stress induced by iAS. Alteration in iAS induced AChE activity is also reversed by GA. It is suggested that GA via its antioxidant potential, has protective effects on iAS induced behavioral deficits and memory alteration. The findings have a strong implication on iAS induced neurological diseases, such as depression, anxiety, Alzheimer's disease and dementia etc.

Impact of 1-day and 4-day MWM training techniques on oxidative and neurochemical profile in rat brain: A comparative study on learning and memory functions

Among multiple behavioral tasks used to assess memory performance, Morris water maze (MWM) is a well-known and reliable conventional behavioral task to monitor spatial memory performance in rodents. Although multiple procedures are employed by researchers for spatial learning training in MWM, but less is known about impact of these training protocol variations on oxidative and neurochemical systems. Therefore, this study aimed to examine whether variations in training protocol will influence spatial memory performance and induce changes in oxidative status and cholinergic and aminergic neurotransmission in rat brain. For this, rats were assigned to four groups; control (unexposed), 1-trial (exposed to single training trial), 1-day (exposed to four training trials for a single day) and 4-day (exposed to four training trials for four days). After conducting training, spatial reference memory performance was determined by performing retention and consolidation probe trials. Rats were then decapitated and their brain and plasma samples were collected for biochemical, oxidative and neurochemical analysis. It was found that spatial reference memory was improved following both 1-day and 4-day training protocols, however, corticosterone levels were raised extensively following 4-day training exposure compared to 1-day training protocol. Similarly, a significant improvement in redox profile and cholinergic and aminergic neurotransmitters was also observed following 1-day training procedure. Thus, 1-day training procedure can be suggested as a better procedure for assessing the spatial memory performance in rats as it has a profound impact on antioxidant status and cholinergic and aminergic neurotransmission in brain. Moreover, use of single-day training procedure can provide a rapid and effective tool for assessing spatial memory in rats compared to prolonged and complicated 4-day training protocol.

Quercetin protects against stress-induced anxiety- and depression-like behavior and improves memory in male mice

The present study evaluates the protective role of Quercetin (Quer), against immobilization stress- induced anxiety, depression and cognition alteration in mice using behavioral and biochemical parameters. 24 adult Albino mice were distributed into 2 groups vehicle (n=12; 1 ml/kg) and Quer injected (n=12; 20 mg/kg/ml). The animals received their respective treatment for 14 days. On day 15, after the drug administration, animals were sub-divided into 4 groups (n=6); (i) unstressed + vehicle; (ii) stressed + vehicle; (iii) unstressed + Quer; (iv) stressed + Quer. On day 16, 24 h after the immobilization stress behavioral activities (light-dark activity, elevated plus maze, Morris water maze, and forced swim test) monitored and then animals were decapitated 1 h after the drug administration. Brain samples were collected for biochemical (antioxidant enzymes, AChE, ACh, 5-HT and its metabolite) analysis. The present study indicates the Quer reversed the stress-induced anxiety and depression, in addition, memory performance was more enhanced in stressed group. Following the treatment of Quer, stress-induced elevation of lipid peroxidation and suppression of antioxidant enzymes were also reversed. Administration of Quer decreased AChE in unstressed, while levels of acetylcholine were increased in vehicle and Quer treated stressed animals. The metabolism of 5-HT was increased in Quer treated stressed than unstressed animals. In conclusion, the present finding showed that Quer could prevent the impairment of antioxidant enzymes and also regulate the serotonergic and cholinergic neurotransmission and produce antianxiety, antidepressant effect and enhance memory following 2 h immobilization stress in mice.

Administration of Allium cepa L. bulb attenuates stress-produced anxiety and depression and improves memory in male mice

In view of anxiolytic, antidepressant and memory strengthen properties of Allium cepa (AC; onion) bulb in various investigations; we aimed to evaluate the useful effects of onion on single immobilization stress -induced biochemical and behavioral changes. Mice in test group were treated with AC powder (200 mg/kg/day), dissolved in water, while the control group were received drinking water for 14 days. After 14 days control and AC treated mice were further divided into unstressed and stressed groups. Animals in the stressed group were subjected to immobilization stress for 2 h. 24-h after the immobilization stress, behavioral activities were monitored. Immobilization stress-induced an anxiogenic behavior in mice subjected to elevated plus maze test (EPM) and light dark activity test (LDA). 2-h immobilization stress-induced depressive behavior in animals measured by forced swim test (FST). Administration of AC attenuated the immobilization stress-induced behavioral deficits. Highest memory performance was observed in stressed mice that were pre-treated with AC in Morris water maze (MWM). Brain lipid peroxidation, antioxidant enzymes (SOD, CAT, GPx) and acetylcholinesterase (AChE) activities were also estimated. Present study suggests a role of antioxidant enzymes in the attenuation of 2-h stress induced anxiety and depression, and enhanced cognitive function as well by AC. The findings therefore suggest that supplementation of AC may be beneficial in the treatment of anxiety, depression and enhancement of memory function.

Magnesium treatment palliates noise-induced behavioral deficits by normalizing DAergic and 5-HTergic metabolism in adult male rats

Magnesium (Mg) is the fourth most abundant biological mineral essential for good health. Neuroprotective, anxiolytic and antidepressant effects of magnesium following stress and brain injuries are well established. In present study, we analyzed the protective effects of magnesium in rats exposed to sub-chronic noise stress. Magnesium Chloride (MgCl2, 100 mg/kg) was administered intraperitoneally once daily for 15 days prior exposure to noise stress. Rats were exposed to noise stress for 4 h after administration of magnesium for 15 days. At the end of treatment behavioral alterations were assessed. Animals were decapitated following behavioral testing and the brains were dissected out for neurochemical estimations by HPLC-EC. Improvement in noise-induced memory deficits as assessed by novel object recognition (NOR) test and elevated plus maze (EPM) test was found in magnesium treated rats. This improvement in noise-induced behavioral deficits following treatment with magnesium may be attributed to a significant decrease (p < 0.01) in dopamine (DA) and serotonin (5-hydroxytryptamine; 5-HT) turnover as compared to control rats observed in present work. These results suggest that treatment with magnesium can attenuate the noise-induced deficits and may be used as a therapy against noise-induced neurodegeneration. Moreover an adequate amount of magnesium in daily diet may help to develop the ability to resist against or cope up with stressful conditions encountered in daily life.

Nootropic and anti-stress effects of rice bran oil in male rats

Rice bran oil (RBO) is an important product of rice bran. It is considered to be one of the most important nutritious oil due to its favorable fatty acid composition and unique composition of naturally occurring biologically active antioxidant compounds. This study was designed to monitor the effects of oral intake of RBO on stress response in rats. RBO was extracted using hexane. Rats were divided into Control and test (RBO-treated). RBO-treated rats were given 0.2 ml/day RBO for 6 weeks. Food intake and body weight changes were monitored weekly. After 6 weeks open field activity and Morris Water Maze (MWM) test were performed. Results showed that weekly cumulative food intake but not body weight were lower in RBO-treated rats during 1st to 5th week of treatment, which were normalized at the end of treatment. Exploratory activity of RBO-treated rats in an open field was increased. Spatial memory in Morris water maze was enhanced in RBO-treated than control rats. An episode of 2 h restraint stress decreased the 24 h food intake of both control and RBO-treated animals. Behavioral deficits were lower in RBO-treated rats. Exposure of 2 h restraint stress increased brain serotonin (5-hydroxytryptamine: 5-HT) metabolism. These increases were lower in RBO-treated restrained than their respective control animals. Serotonergic neurotransmitter mechanism is implicated in stress. The findings of the study show beneficial effects of RBO in learning and memory functions. Moreover, the study also highlights the attenuating effect of RBO on stress induced behavioral and neurochemical effects in rats.

Short term cadmium administration dose dependently elicits immediate biochemical, neurochemical and neurobehavioral dysfunction in male rats

Cadmium is a toxic environmental and industrial pollutant. Cadmium toxicity has been reported to produce biochemical and behavioral dysfunction that may cause adverse effects on several organs including the central nervous system. The present study was designed to investigate the neurotoxic effects of Cadmium Chloride (CdCl2) at three different doses by using different behavioral models. Lipid peroxidation (LPO), superoxide dismutase (SOD) and acetylcholinesterase (AChE) activities were also monitored following acute intraperitoneal injection of cadmium. Twenty four adult locally bred Albino Wistar rats were divided into control and 3 test groups (n = 6). Control rats were injected intraperitoneally with saline (0.9% NaCl) and test groups were injected with CdCl2 (1 mg/kg, 2 mg/kg and 3 mg/kg) dissolved in physiological solution. Behavioral activities of rats were monitored after 1 h of cadmium injection. Locomotor activity and depression-like symptoms were measured by Open Field Test (OFT) and Forced Swimming Test (FST) respectively. Anxiety like behavior was monitored using Light-dark Transition (LDT) test and memory functions of rats were assessed by Morris Water Maze test (MWM). In the present study acute cadmium administration dose dependently increased anxiety in rats as compared to control rats. A significant increase in depression-like symptoms was also exhibited by cadmium treated rats. These behavioral dysfunctions may be attributed to the decreased superoxide dismutase (SOD) activity and simultaneously increased brain lipid peroxidation (LPO). Moreover learning and memory assessed by MWM showed dose dependent impairment in memory function in cadmium treated rats as compared to control rats. Acetylcholinesterase (AChE) activity was also decreased in brains of cadmium administered rats. It is suggested in this study that behavioral, biochemical and neurochemical dysfunctions caused by acute cadmium administration occur in a dose dependent manner.

Age-related learning and memory deficits in rats: role of altered brain neurotransmitters, acetylcholinesterase activity and changes in antioxidant defense system

Oxidative stress from generation of increased reactive oxygen species or free radicals of oxygen has been reported to play an important role in the aging. To investigate the relationship between the oxidative stress and memory decline during aging, we have determined the level of lipid peroxidation, activities of antioxidant enzymes, and activity of acetylcholine esterase (AChE) in brain and plasma as well as biogenic amine levels in brain from Albino-Wistar rats at age of 4 and 24 months. The results showed that the level of lipid peroxidation in the brain and plasma was significantly higher in older than that in the young rats. The activities of antioxidant enzymes displayed an age-dependent decline in both brain and plasma. Glutathione peroxidase and catalase activities were found to be significantly decreased in brain and plasma of aged rats. Superoxide dismutase (SOD) was also significantly decreased in plasma of aged rats; however, a decreased tendency (non-significant) of SOD in brain was also observed. AChE activity in brain and plasma was significantly decreased in aged rats. Learning and memory of rats in the present study was assessed by Morris Water Maze (MWM) and Elevated plus Maze (EPM) test. Short-term memory and long-term memory was impaired significantly in older rats, which was evident by a significant increase in the latency time in MWM and increase in transfer latency in EPM. Moreover, a marked decrease in biogenic amines (NA, DA, and 5-HT) was also found in the brain of aged rats. In conclusion, our data suggest that increased oxidative stress, decline of antioxidant enzyme activities, altered AChE activity, and decreased biogenic amines level in the brain of aged rats may potentially be involved in diminished memory function.

Alteration in plasma corticosterone levels following long term oral administration of lead produces depression like symptoms in rats

Lead toxicity is known to induce a broad range of physiological, biochemical and behavioral dysfunctions that may result in adverse effects on several organs, including the central nervous system. Long-term exposure to low levels of lead (Pb(2+)) has been shown to produce behavioral deficits in rodents and humans by affecting hypothalamic-pituitary-adrenal (HPA) axis. These deficits are thought to be associated with altered brain monoamine neurotransmission and due to changes in glucocorticoids levels. This study was designed to investigate the effects of Pb(2+)exposure on growth rate, locomotor activity, anxiety, depression, plasma corticosterone and brain serotonin (5-HT) levels in rats. Rats were exposed to lead in drinking water (500 ppm; lead acetate) for 5 weeks. The assessment of depression was done using the forced swimming test (FST). Estimation of brain 5-HT was determined by high-performance liquid chromatography with electrochemical detection. Plasma corticosterone was determined by spectrofluorimetric method. The present study showed that long term exposure to Pb(2+) significantly decreased the food intake followed by the decrease in growth rate in Pb(2+)exposed rats as compared to control group. No significant changes in open field activity were observed following Pb(2+)exposure while significant increase in anxiogenic effect was observed. Increased plasma corticosterone and decreased 5-HT levels were exhibited by Pb(2+)exposed rats as compared to controls. A significant increase in depressive like symptoms was exhibited by Pb(2+)exposed rats as compared to control rats. The results are discussed in the context of Pb(2+) inducing a stress-like response in rats leading to changes in plasma corticosterone and brain 5-HT levels via altering tryptophan pyrrolase activity.

Streptozotocin-induced insulin deficiency leads to development of behavioral deficits in rats

Diabetes mellitus is one of the most common serious metabolic disorders in humans that develops due to diminished production of insulin (type I) or resistance to its effect (type II and gestational). The present study was designed to determine the neuropsychological deficits produced following streptozotocin-induced diabetes in rats. Rats were made diabetic by the intra-peritoneal administration of 60 mg/kg streptozotocin (STZ) which induces type-1 diabetes by the destruction "β-cells" of pancreas. Body weight, food and water intake was monitored daily. Open field test (OFT) model, forced swim test (FST) and Morris water maze (MWM) model were performed for the evaluation of ambulation, depression-like symptoms and memory effects, respectively. After 10 days of diabetes induction the exploratory activity of rats was monitored by OFT while depression-like symptoms and memory effects in rats were analyzed by FST and MWM. Results showed that there was no significant effect of STZ-induced diabetes on body weight but food and water intake of STZ-induced diabetic rats was significantly increased. Exploratory activity was significantly decreased and short-term and long-term memory was significantly impaired while the depression-like symptoms was significantly increased in STZ diabetic rats. Thus, it may be suggested that STZ-induced diabetes alters the brain functions and may play an important role in the pathophysiology of certain behavioral deficits like depression, impaired learning and memory functions related to diabetes. This finding may be of relevance in the pathophysiology and in the clinical picture, which could be related to an altered brain serotonin metabolism and neurotransmission and may possibly be related to neuropsychiatric disorders in diabetic patients.