Chrysin mitigates neuronal apoptosis and impaired hippocampal neurogenesis in male rats subjected to D-galactose-induced brain aging.

Oxidative stress-induced neuronal apoptosis is primarily involved in brain aging and impaired hippocampal neurogenesis. Long-term D-galactose administration increases oxidative stress related to brain aging. Chrysin, a subtype of flavonoids, exhibits neuroprotective effects, particularly its antioxidant properties. To elucidate the neuroprotection of chrysin on neuronal apoptosis and an impaired hippocampal neurogenesis relevant to oxidative damage in D-galactose-induced brain aging, male Sprague Dawley rats were allocated into vehicle control, D-galactose, chrysin, and cotreated rats. The rats received their respective treatments daily for 8 weeks. The reactions of scavenging enzymes, protein regulating endogenous antioxidant defense, and anti-apoptotic protein expression were significantly reduced in the hippocampus and prefrontal cortex of the animals receiving D-galactose. Conversely, product of oxidative damage and apoptotic protein expressions were significantly elevated in both cortical areas of the D-galactose group. In hippocampal neurogenesis, significant upregulation of cell cycle arrest and decrease in differentiated protein expression were detected after D-galactose administration. Nevertheless, chrysin supplementation significantly mitigated all negative effects in animals receiving D-galactose. This study demonstrates that chrysin likely attenuates brain aging induced by D-galactose by enhancing scavenging enzyme activities and reducing oxidative stress, neuronal apoptosis, and the impaired hippocampal neurogenesis.

Caffeic acid protects against l-methionine induced reduction in neurogenesis and cognitive impairment in a rat model.

l-methionine (L-met) is a substantial non-polar amino acid for normal development. L-met is converted to homocysteine that leads to hyperhomocysteinemia and subsequent excessive homocysteine in serum resulting in stimulating oxidative stress and vascular dementia. Several studies have found that hyperhomocysteine causes neuronal cell damage, which leads to memory impairment. Caffeic acid is a substrate in phenolic compound discovered in plant biosynthesis. Caffeic acid contains biological antioxidant and neuroprotective properties. The neuroprotective reaction of caffeic acid can protect against the brain disruption from hydrogen peroxide produced by oxidative stress. It also enhances GSH and superoxide dismutase activities, which protect against neuron cell loss caused by oxidative stress in the hippocampus. Hence, we investigated the protective role of caffeic acid in hippocampal neurogenesis and cognitive impairment induced by L-met in rats. Six groups of Sprague Dawley rats were assigned including control, L-met (1.7 g/kg/day), caffeic acid (20, 40 mg/kg), and L-met + caffeic acid (20, 40 mg/kg) groups. Spatial and recognition memories were subsequently examined using novel object location (NOL) and novel object recognition (NOR) tests. Moreover, the immunofluorescence technique was performed to detect Ki-67/RECA-1, bromodeoxyuridine (BrdU)/NeuN and p21 markers to represent hippocampal neurogenesis changes. The results revealed decreases in vasculature related cell proliferation and neuronal cell survival. By contrast, cell cycle arrest was increased in the L-met group. These results showed the association of the spatial and recognition memory impairments. However, the deterioration can be restored by co-administration with caffeic acid.

Toxicity Profiles of Kleeb Bua Daeng Formula, a Traditional Thai Medicine, and Its Protective Effects on Memory Impairment in Animals.

Kleeb Bua Daeng (KBD) formula has long been used in Thailand as a traditional herbal medicine for promoting brain health. Our recent reports illustrated that KBD demonstrates multiple modes of action against several targets in the pathological cascade of Alzheimer's disease (AD). The main purpose of the present study was to determine the protective effect and mechanism of KBD in amyloid beta (Aß)-induced AD rats and its toxicity profiles. Pretreatment with the KBD formula for 14 days significantly improved the short- and long-term memory performance of Aß-induced AD rats as assessed by the Morris Water Maze (MWM) and object-recognition tests. KBD treatment increased the activities of the antioxidant enzymes catalase, superoxide dismutase, and glutathione peroxidase; reduced the malondialdehyde content, and; decreased the acetylcholinesterase activity in the rat brain. An acute toxicity test revealed that the maximum dose of 2000 mg/kg did not cause any mortality or symptoms of toxicity. An oral, subchronic toxicity assessment of KBD at doses of 125, 250, and 500 mg/kg body weight/day for 90 days showed no adverse effects on behavior, mortality, hematology, or serum biochemistry. Our investigations indicate that KBD is a nontoxic traditional medicine with good potential for the prevention and treatment of AD.

Melatonin Attenuates Methotrexate-Induced Reduction of Antioxidant Activity Related to Decreases of Neurogenesis in Adult Rat Hippocampus and Prefrontal Cortex.

Previous studies have revealed that the side effects of anticancer drugs induce a decrease of neurogenesis. Methotrexate (MTX), one of anticancer drugs, can induce lipid peroxidation as an indicator of oxidative stress in the brain. Melatonin has been presented as an antioxidant that can prevent oxidative stress-induced neuronal damage via the activation of antioxidant enzymes associated with the increase of neurogenesis. The aims of the present study are to examine the neuroprotective effect of melatonin on the neurotoxicity of MTX on neurogenesis and the changes of protein expression and antioxidant enzyme levels in adult rat hippocampus and prefrontal cortex (PFC). Male Sprague-Dawley rats were assigned into four groups: vehicle, MTX, melatonin, and melatonin+MTX groups. The vehicle group received saline solution and 10% ethanol solution, whereas the experimental groups received MTX (75 mg/kg, i.v.) and melatonin (8 mg/kg, i.p.) treatments. After the animal examination, the brains were removed for p21 immunofluorescence staining. The hippocampus and PFC were harvested for Western blot analysis and biochemical assessments of malondialdehyde (MDA), catalase (CAT), glutathione peroxidase (GPX), and superoxide dismutase (SOD). The immunofluorescence result showed that coadministration with melatonin diminished p21-positive cells in the hippocampal dentate gyrus, indicating a decrease of cell cycle arrest. Melatonin reduced the levels of MDA and prevented the decline of antioxidant enzyme activities in rats receiving MTX. In the melatonin+MTX group, the protein expression results showed that melatonin treatment significantly upregulated synaptic plasticity and an immature neuron marker through enhancing brain derived neurotrophic factor (BDNF) and doublecortin (DCX), respectively. Moreover, melatonin ameliorated the antioxidant defense system by improving the nuclear factor erythroid 2-related factor 2 (Nrf2) in rats receiving MTX. These findings suggested that the effects of melatonin can ameliorate MTX toxicity by several mechanisms, including an increase of endogenous antioxidants and neurogenesis in adult rat hippocampus and PFC.

Neuroprotective properties of chrysin on decreases of cell proliferation, immature neurons and neuronal cell survival in the hippocampal dentate gyrus associated with cognition induced by methotrexate.

Methotrexate (MTX) is a drug widely used for chemotherapy and can reduce cancer cell production by inhibiting dihydrofolate reductase and decreasing cancer cell growth. MTX has a neurotoxic effect on neural stem and glial cells, leading to memory deficits. Chrysin is a natural flavonoid that contains essential biological activities, such as neuroprotective and cognitive-improving properties. Therefore, the aim of the present study was to investigate the protective effect of chrysin against MTX-induced memory impairments related to hippocampal neurogenesis. Seventy-two male Sprague Dawley rats were divided into six groups: control, MTX, chrysin (10 and 30 mg/kg), and MTX+ chrysin (10 and 30 mg/kg) groups. Chrysin (10 and 30 mg/kg) was administered by oral gavage for 15 days. MTX (75 mg/kg) was administered by intravenous injection on days 8 and 15. Spatial and recognition memories were evaluated using the novel object location (NOL) and novel object recognition (NOR) tests, respectively. Moreover, cell proliferation, neuronal cell survival, and immature neurons in the subgranular zone of the hippocampal dentate gyrus were quantified by Ki-67, bromodeoxyuridine/neuronal nuclear protein (BrdU/NeuN), and doublecortin (DCX) immunohistochemistry staining. The results of the MTX group demonstrated that spatial and recognition memories were both impaired. Furthermore, cell division reduction, neuronal cell survival reduction, and immature neuron decreases were detected in the MTX group and not observed in the co-administration groups. Therefore, these results revealed that chrysin could alleviate memory and neurogenesis impairments in MTX-treated rats.

Caffeic Acid Alleviates Memory and Hippocampal Neurogenesis Deficits in Aging Rats Induced by D-Galactose.

Hippocampal neurogenesis occurs throughout life, but it declines with age. D-galactose (D-gal) enhances cellular senescence through oxidative stress leading to neurodegeneration and memory impairment. Caffeic acid (CA) acts as an antioxidant via decreasing brain oxidative stress. This study aims to investigate the advantages of CA in alleviating the loss of memory and neurogenesis production in the hippocampus in aged rats activated by D-gal. Fifty-four male Sprague-Dawley rats were unpredictably arranged into six groups. In the D-gal group, rats were administered D-gal (50 mg/kg) by intraperitoneal (i.p.) injection. For the CA groups, rats received 20 or 40 mg/kg CA by oral gavage. In the co-treated groups, rats received D-gal (50 mg/kg) and CA (20 or 40 mg/kg) for eight weeks. The results of novel object location (NOL) and novel object recognition (NOR) tests showed memory deficits. Moreover, a decline of neurogenesis in the hippocampus was detected in rats that received D-gal by detecting rat endothelial cell antigen-1 (RECA-1)/Ki-67, 5-bromo-2'-deoxyuridine (BrdU)/neuronal nuclear protein (NeuN), doublecortin (DCX) by means of staining to evaluate blood vessel associated proliferating cells, neuronal cell survival and premature neurons, respectively. By contrast, CA attenuated these effects. Our results postulate that CA attenuated the impairment of memory in D-gal-stimulated aging by up-regulating levels of hippocampal neurogenesis.

Clausena Harmandiana root extract attenuated cognitive impairments via reducing amyloid accumulation and neuroinflammation in Aß1-42-induced rats.

BACKGROUND: Alzheimer's disease (AD) pathogenesis is associated with amyloid-ß (Aß)-induced neuroinflammation. In AD, the activation of microglia caused by Aß accumulation is followed by the synthesis and release of pro-inflammatory cytokines, including interleukin-1ß (IL-1ß) and tumor necrosis factor-α (TNFα), and ultimately leads to cognitive impairments. Clausena harmandiana (CH) is a medicinal plant in the Rutaceae family and has been used in folk medicine to relieve illnesses such as stomachache and headache, and as a health tonic. Interestingly, CH root extract (CHRE) has several anti-inflammatory and other pharmacological activities, but there are no studies in AD-like animal models. OBJECTIVES: This study aims to evaluate the effects of CHRE on cognitive impairments, increased Aß1-42 protein levels, and neuroinflammation in Aß1-42-induced rats. METHODS: Forty-eight adult male Sprague-Dawley rats (250-300 g) were randomly divided into 6 groups (n = 8) of the sham control, V + Aß, CB + Aß CHRE125 + Aß, CHRE250 + Aß, and CHRE500 + Aß. Sodium carboxymethylcellulose, Celebrex (10 mg/kg BW) and CHRE (125, 250, and 500 mg/kg BW) were given orally or without any treatment for 35 days. On day 21, aggregated Aß1-42 at a concentration of 1 µg/µl were injected into both lateral ventricles (1 µl/side) of all treated rats, while sterilized normal saline were injected to untreated rats. Ten days later, the novel object recognition test was performed to assess their recognition memory. At the end of the test period, an overdose of thiopental sodium (120 mg/kg BW) and transcardial perfusion with 0.9% normal saline solution were used to euthanize all rats. Then Aß1-42 protein levels and the expression of inflammatory markers (CD11b-positive microglia, IL-1ß, and TNFα) were investigated in the cerebral cortex and hippocampus. RESULTS: Pretreatment with CHRE at all doses could attenuate short- and long-term impairments in recognition memory. Additionally, CHRE also inhibited the increase of Aß1-42 protein levels and the expression of inflammatory markers in both brain regions as well as receiving Celebrex. CONCLUSIONS: This suggests that preventive treatment of CHRE might be a potential therapy against cognitive impairments via reducing Aß1-42 protein levels and neuroinflammation caused by Aß1-42.

Hesperidin Reduces Memory Impairment Associated with Adult Rat Hippocampal Neurogenesis Triggered by Valproic Acid.

Treatment with valproic acid (VPA) deteriorates hippocampal neurogenesis, which leads to memory impairment. Hesperidin (Hsd) is a plant-based bioflavonoid that can augment learning and memory. This study aimed to understand the effect of Hsd on the impairment of hippocampal neurogenesis and memory caused by VPA. The VPA (300 mg/kg) was administered by intraperitoneal injection twice daily for 14 days, and Hsd (100 mg/kg/day) was administered by oral gavage once a day for 21 days. All rats underwent memory evaluation using the novel object location (NOL) and novel object recognition (NOR) tests. Immunofluorescent staining of Ki-67, BrdU/NeuN, and doublecortin (DCX) was applied to determine hippocampal neurogenesis in cell proliferation, neuronal survival, and population of the immature neurons, respectively. VPA-treated rats showed memory impairments in both memory tests. These impairments resulted from VPA-induced decreases in the number of Ki-67-, BrdU/NeuN-, and DCX-positive cells in the hippocampus, leading to memory loss. Nevertheless, the behavioral expression in the co-administration group was improved. After receiving co-administration with VPA and Hsd, the numbers of Ki-67-, BrdU/NeuN-, and DCX-positive cells were improved to the normal levels. These findings suggest that Hsd can reduce the VPA-induced hippocampal neurogenesis down-regulation that results in memory impairments.

Melatonin Ameliorates Valproic Acid-Induced Neurogenesis Impairment: The Role of Oxidative Stress in Adult Rats.

BACKGROUND: Valproic acid (anticonvulsant medication) has been found to inhibit histone deacetylase activity and suppress hippocampal neurogenesis, which causes memory impairment in both humans and rodents. The neurohormone melatonin, which regulates mammalian seasonal and circadian physiology, has recently been shown to have neuroprotective properties, counteracting memory impairment associated with VPA-caused hippocampal neurogenesis reduction. This study is aimed at investigating the molecular mechanisms of melatonin associated with VPA-induced hippocampal neurogenesis and memory impairment. METHODS: Male Spraque-Dawley rats received VPA (300 mg/kg) twice daily or melatonin (8 mg/kg/day) or some rats were given melatonin for 14 days during VPA administration. RESULTS: The VPA-treated rats showed a significant increase in malondialdehyde (MDA) levels in the hippocampus and p21-positive cells in the subgranular zone (SGZ) of the dentate gyrus (DG) but decreased superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPx) activities. Moreover, VPA significantly decreased levels of nestin, Notchl, nuclear factor erythroid 2-related factor 2 (Nrf2), doublecortin (DCX), sex determining region Y-box 2 (SOX2), and brain-derived neurotrophic factor (BDNF). CONCLUSIONS: We found that melatonin was able to counteract these neurotoxic effects, acting as a neuroprotectant in VPA-induced memory hippocampal neurogenesis impairment by preventing intracellular oxidative stress and increasing antioxidant activity.

Melatonin Protects against the Side-Effects of 5-Fluorouracil on Hippocampal Neurogenesis and Ameliorates Antioxidant Activity in an Adult Rat Hippocampus and Prefrontal Cortex.

Melatonin is an endogenous hormone that exhibits antioxidant functions and neuroprotective effects. The hippocampus and the prefrontal cortex (PFC) play an important role linked to working memory. 5-fluorouracil (5-FU) can induce oxidative stress and reduce neurogenesis in the subgranular zone (SGZ) of the dentate gyrus in a rat hippocampus and these alterations are related to working memory deficits. This study aimed to determine the effect of melatonin on 5-FU-induced oxidative stress that interferes with the antioxidant enzymes and protein expression levels in a rat hippocampus and PFC. A total of 68 male Sprague Dawley rats were divided into four groups: vehicle, 5-FU, melatonin and melatonin+5-FU groups. Rats were administered 5-FU (25 mg/kg, i.v.) on days 9, 12, 15, 18 and 21 and received melatonin (8 mg/kg, i.p.) at 19:00 from day 1 to day 21 of the experiment. Lipid peroxidation was assessed by measuring malondialdehyde (MDA) levels. Antioxidant enzyme levels including glutathione peroxidase (GPX), catalase (CAT) and superoxide dismutase (SOD) were determined. p21 immunofluorescence staining and Western blotting were used to detect the cell cycle arrest and protein expression of the nuclear factor erythroid 2-related factor 2 (Nrf2), doublecortin (DCX) and brain derived neurotrophic factor (BDNF), respectively. The results showed that melatonin reduced the number of p21-positive cells in the SGZ of the dentate gyrus and increased Nrf2, DCX and BDNF protein expression in rats treated with 5-FU. Moreover, melatonin restored antioxidant enzyme levels and reduced oxidative stress in the hippocampus and PFC caused by 5-FU. These findings reveal a mechanism of the neuroprotective properties of melatonin against 5-FU in a rat hippocampus and PFC.

Melatonin attenuates 5-fluorouracil-induced spatial memory and hippocampal neurogenesis impairment in adult rats.

AIMS: Treatment with 5-fluorouracil (5-FU) can cause impairment to adult hippocampal neurogenesis, resulting in cognitive deficits. As melatonin has been shown to enhance memory and hippocampal neurogenesis in animal models, this research investigated the neuroprotective effects of melatonin against spatial memory and hippocampal neurogenesis impairment in 5-fluorouracil (5-FU)-treated rats. MATERIALS AND METHODS: Four-Five weeks old male Spraque-Dawley rats weighing between 180 and 200 g were used. Animals were maintained under standard laboratory conditions with 25 °C and 12 h light/dark cycle. Animal were administered intravenous (i.v.) injections of 5-FU (25 mg/kg) 5 times every 3 days starting on day 9 of the experiment. The rats were divided into preventive, recovery, and throughout groups and co-treated with melatonin (8 mg/kg, i.p.) once daily (at 7.00 pm) for 21 days prior to, after, and throughout 5-FU treatment, respectively. Spatial memory was assessed using a novel object location (NOL) test. Hippocampal neurogenesis was then examined using Ki67, bromodeoxyuridine (BrdU), and doublecortin (DCX) immunohistochemistry staining. KEY FINDINGS: Melatonin administration was able to both protect the subjects from and reverse spatial memory deficits. 5-FU was also found to reduce the generation of hippocampal newborn neurons. However, co-treatment with melatonin ameliorated the reductions in neurogenesis caused by 5-FU. SIGNIFICANCE: These findings suggest that melatonin administration was able to ameliorate the 5-FU-induced spatial memory deficits associated with neurogenesis. The present work will be valuable for patients who suffer memory deficits from 5-FU chemotherapy.

Effect of combined extracts of aged garlic, ginger, and chili peppers on cognitive performance and brain antioxidant markers in Aß-induced rats.

A combination of aged garlic, ginger, and chili peppers extracts (AGC) was studied by high-performance liquid chromatography, 2,2-diphenyl-1-picrylhydrazyl, and ferric-reducing antioxidant assays, and oxidative stress markers were analyzed in Aß1-42-induced rats. The AGC was orally administered to Wistar rats at doses of 125, 250, and 500 mg/kg body weight (AGC125, AGC250, AGC500, respectively) for 64 days. At day 56, Aß1-42 was injected via both sides of the lateral ventricles. The effects of the AGC on spatial and recognition memory were examined using a Morris water maze and novel object recognition tasks. Rats induced with Aß1-42 exhibited obvious cognitive deficits, as demonstrated by their increased escape latency time (ET) and decreased retention time (RT) and percentage of discriminative index (DI). When compared with the control group, all AGC-treated rats showed significantly shorter ETs and higher DIs during the 5-min delay testing phase. Rats treated with AGC250 also had significantly longer RTs. Administration of Aß1-42 significantly increased malondialdehyde (MDA) levels and decreased superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) levels in the rat brain homogenate. Pretreatment with the AGC caused significant increases in SOD, GPx, and CAT activities, as well as a significant decrease in MDA in the rat brain homogenates after Aß-induced neurotoxicity. Our results suggested that an AGC may ameliorate cognitive dysfunction in Aß-treated rats due to its role in the upregulation of SOD, GPx, and CAT.

Valproic acid withdrawal ameliorates impairments of hippocampal-spatial working memory and neurogenesis.

Valproic acid (VPA), an agent that is used to treat epileptic seizures, can cause spatial memory impairment in adults and children. This effect is thought to be due to the ability of VPA to inhibit neurogenesis in the hippocampus, which is required for learning. We have previously used an animal model to show that VPA significantly impairs hippocampal-spatial working memory and inhibits neuronal generation in the sub-granular zone of the dentate gyrus. As there are patient reports of improvements in memory after discontinuing VPA treatment, the present study investigated the recovery of both spatial memory and hippocampal neurogenesis at two time points after withdrawal of VPA. Male Wistar rats were given intraperitoneal injections of 0.9% normal saline or VPA (300 mg/kg) twice a day for 10 d. At 1, 30, or 45 d after the drug treatment, the novel object location (NOL) test was used to examine spatial memory; hippocampal cell division was counted using Ki67 immunohistochemistry, and levels of brain-derived neurotrophic factor (BDNF) and Notch1 were measured using western immunoblotting. Spatial working memory was impaired 1 and 30 d after the final administration, but was restored to control levels by 45 d. Cell proliferation had increased to control levels at 30 and 45 d. Both markers of neurogenesis (BDNF and Notch1 levels) had returned to control levels at 45 d. These results demonstrate that memory recovery occurs over a period of six weeks after discontinuing VPA treatment and is preceded by a return of hippocampal neurogenesis to control levels.

Melatonin protects against methotrexate-induced memory deficit and hippocampal neurogenesis impairment in a rat model.

Methotrexate (MTX) is a chemotherapy agent linked to cognitive deficits in cancer patients received chemotherapy treatment. MTX decreases cell proliferation in the hippocampus, which is concomitant with cognitive deficits in animal models. The present study aimed to investigate the disadvantages of MTX on cognition associated with cell division, survival, and immature neurons involved in hippocampal neurogenesis, as well as the practical neuroprotective effects of melatonin. Male Sprague Dawley rats were given two injections of MTX (75 mg/kg) on days 8 and 15 followed by Leucovorin (LCV, 6 mg/kg) at hours 18, 26, 42, 50 via i.p. injection. Some rats received co-treatment with melatonin (8 mg/kg, i.p. injection) for 15 days before and during MTX administration (preventive), 15 days after MTX administration (recovery), or both (30 days total; throughout). Hippocampal-dependent memory was examined using novel objection location (NOL) and novel object recognition (NOR) tests. Cell division, survival and immature neurons in the subgranular zone (SGZ) in the hippocampus were evaluated using immunofluorescence staining. Rats given MTX/LCV were found to have cognitive memory deterioration based on the NOL and NOR tests. Moreover, reductions in cell division, cell survival, and the numbers of immature neurons were detected in the MTX/LCV group when compared to the controls. This damage was not observed in rats in the preventive, recovery, or throughout groups. These findings reveal that melatonin has the potential to diminish the negative effects of MTX on memory and neurogenesis. This also indicates the benefit of melatonin co-administration in patients who undergo chemotherapy treatment.

Protective effects of melatonin against valproic acid-induced memory impairments and reductions in adult rat hippocampal neurogenesis.

Valproic acid (VPA) is widely used in the treatment of epilepsy. However, VPA has been revealed to impair memory of both humans and animals. The adverse effects of VPA are associated with reductions in hippocampal neurogenesis and memory. There are neuroprotective properties exerted by melatonin. Therefore, we investigated the protective effects of melatonin against the reductions of memory and neurogenesis caused by VPA. Male Sprague-Dawley rats received VPA (300 mg/kg) twice a day for 14 days, or melatonin (8 mg/kg/day) for 14 days, or co-treatment with VPA and melatonin for either 14 days (preventive and recovery groups) or 28 days (throughout group). Novel object location and novel object recognition tests were used to assess spatial memory and non-spatial memory, respectively. Proliferation, survival, and immature neurons in the subgranular zone (SGZ) were examined using immunohistochemistry. Rats showed decreases in proliferation, survival, and immature neurons in the SGZ, which were related to impairments in spatial and non-spatial memory. These behavioral changes were prevented by co-administration with melatonin. In addition, the decreasing of the hippocampal neurogenesis was improved to control levels, which had received co-administration with melatonin (preventive, recovery, and throughout). It is noteworthy that rats receiving melatonin alone showed a significant diversity of proliferation, survival and immature neurons compared to the control rats. These findings suggest that melatonin is able to prevent the spatial and non-spatial memory impairments and a reduction in hippocampal neurogenesis simultaneously induced by VPA. Our results provide a feasible way to prevent this loss using melatonin.

Neuroprotective Properties of Asiatic Acid against 5-Fluorouracil Chemotherapy in the Hippocampus in an Adult Rat Model.

5-fluorouracil or 5-FU (a chemotherapeutic medication) has been revealed to induce memory deficits in many cancer patients. Asiatic acid (AA) is a triterpenoid extract from Centella asiatica. This compound can ameliorate intracellular oxidative stress caused by chemotherapy drugs. Recent studies have shown that AA is capable of inhibiting neuronal generation and memory deficit produced by 5-FU chemotherapy. This study aimed to assess the molecular mechanisms of AA related to hippocampal neurogenesis and memory in rats receiving 5-FU. Male Sprague Dawley rats were given AA (30 mg/kg) orally and given 5-FU (25 mg/kg) by i.v. injection 5 times. Some rats were given AA for 20 days before and during 15-FU treatment (preventive), some received AA for 20 days after 5-FU treatment (recovery), and some underwent treatment with AA throughout the time of the experiment (throughout) for 40 days. Treatment with 5-FU caused significant reductions in Notch1, sex determining region Y-box 2 (SOX2), nestin, doublecortin (DCX), and nuclear factor erythroid 2-related factor 2 (Nrf2) levels within the hippocampus. In addition, 5-FU significantly increased p21 positive cell number in the subgranular zone (SGZ) and malondialdehyde (MDA) levels in the hippocampus. Administration with both AA and 5-FU in prevention and throughout was able to prevent decreases in Notch1 SOX2, nestin, DCX, and Nrf2 caused by 5-FU. Treatment with AA also led to decreases in p21 positive cells and MDA levels in the hippocampus. These findings exhibit that AA has the ability to counteract the down-regulation of neurogenesis within the hippocampus and memory deficits caused by 5-FU via inhibiting oxidative stress and increasing neuroprotective properties.

Classification and incidence of pterion patterns of Thai skulls / Clasificación e incidencia de los patrones de pterion en cráneos de Tailandia

SUMMARY: The pterion, a landmark for neurosurgery, is the weakest part of the skull owing to relatively thin bone. Variant patterns of pterion can confuse the clinicians during diagnosis of the lateral skull fractures in emergency situations. Thedifferent pterion types of many races have been reported but not of Thais. In this study; therefore, we investigated the incidence of sutural pterion patterns on of Thai skulls. The infratemporal fossa of 110 sides from 55 dried skulls identified as Thais were observed and classified for individual pterion types. The results showed that the pterion patterns can be classified into 4 types; spheno-parietal (87.27 %), fronto-temporal (4.55 %), uni-epipteric (6.36 %), and multi-epipteric (1.82 %) types. It was found that the spheno-parietal type was dominant in males (61.81 %) than in females (25.45 %). The majority of the skulls showed bilateral symmetry (85.45 %) in all types and the unilateral ones were far less (14.55 %). In bilateral pterion incidence, the spheno-parietal type was approximately 93.61 % while the uni-epipteric type was not found. Moreover, the bilateral multi-epipteric type was found only in one female skull (2.13 %). These findings will be useful for the radiologists and the neurosurgeons concerning lateral skull fractures in emergency diagnosis.

RESUMEN: El pterion es un punto de referencia para la neurocirugía, y es la parte más débil del cráneo debido a estar conformado por hueso relativamente delgado. Los diversos patrones de pterion pueden confundir a los clínicos durante el diagnóstico de fracturas laterales de cráneo en situaciones de emergencia. Con excepción de los tailandeses, diferentes tipos de pterion se han reportado en muchas razas. hemos investigado la incidencia de diversos patrones de pterion en cráneos de Tailandia. Analizamos 110 fosas infratemporales, correspondientes a 55 cráneos secos del Noreste de Tailandia y se clasificaron de acuerdo al tipo de pterion. Los resultados mostraron que el pterion puede clasificarse en 4 tipos: esfeno-parietal (87,27 %), fronto-temporal (4,55 %), epiptérico (3,63 %) y multi-epiptérico (1,81 %). Se encontró que el tipo esfeno-parietal tuvo mayor incidencia en hombres (61,81 %) que en mujeres (25,45 %). Además, la incidencia de simetría bilateral (85,45 %) fue mayor que la unilateral (14,55 %). A nivel bilateral, el tipo esfeno-parietal fue de 93,61 %, mientras que el tipo epiptérico no se observó. Por otra parte, el tipo multiepiptérico fue encontrado bilateralmente en un solo cráneo femenino (2,13 %). Esta incidencia puede ser utilizada como un conocimiento básico para los radiólogos tailandeses sobre las fracturas laterales del cráneo en un diagnóstico de emergencia.

Asiatic acid protects against cognitive deficits and reductions in cell proliferation and survival in the rat hippocampus caused by 5-fluorouracil chemotherapy.

The chemotherapy drug, 5-fluorouracil (5-FU), has been reported to cause cognitive impairments in cancer patients. The drug also reduces cell proliferation and survival in the brain. Asiatic acid (AA) is a triterpene compound found in Centella asiatica that can protect against reduction of neurogenesis in the hippocampus and memory deficits induced by valproic acid (VPA). In the present study, we investigated the preventive effects of AA on the deficits in spatial working memory and cell proliferation and survival caused by 5-FU chemotherapy in a rat model. Male Sprague Dawley rats received 5-FU (5 i.v. injections, 25 mg/kg) on day 8, 11, 14, 17 and 20 of the study. This was co-administered with AA (30 mg/kg, oral gavage tube) either 20 days before receiving 5-FU (preventive), after receiving 5-FU (recovery), or for the entire period of the experiment (throughout). Spatial working memory was determined using the novel object location (NOL) test and hippocampal cell proliferation and survival of dividing cells were quantified using immunohistochemistry. Rats in the 5-FU alone and recovery groups showed memory deficits in the NOL test and reductions in cell proliferation and cell survival in the subgranular zone (SGZ) of the hippocampal dentate gyrus. Rats in the control, AA alone, and both preventive and throughout co-administration groups, however, did not exhibit these characteristics. The results showed that 5-FU chemotherapy impaired memory and reduced cell proliferation and cell survival in the SGZ of the hippocampal dentate gyrus. However, these impairments in the animals receiving 5-FU chemotherapy were restored to control levels when AA was co-administered before and during 5-FU treatment. These data demonstrate that AA can prevent the spatial working memory and hippocampal neurogenesis impairments caused by 5-FU chemotherapy.

Effects of Aged Garlic Extract on Cholinergic, Glutamatergic and GABAergic Systems with Regard to Cognitive Impairment in Aß-Induced Rats.

Alzheimer's disease (AD) has been linked to the degeneration of central cholinergic and glutamatergic transmission, which correlates with progressive memory loss and the accumulation of amyloid-ß (Aß). It has been claimed that aged garlic extract (AGE) has a beneficial effect in preventing neurodegeneration in AD. Therefore, the objective of this study was to investigate the effects of AGE on Aß-induced cognitive dysfunction with a biochemical basis in the cholinergic, glutamatergic, and GABAergic systems in rats. Adult male Wistar rats were orally administered three doses of AGE (125, 250, and 500 mg/kg) daily for 65 days. At day 56, they were injected with 1 µL of aggregated Aß (1-42) into each lateral ventricle, bilaterally. After six days of Aß injection, the rats' working and reference memory was tested using a radial arm maze. The rats were then euthanized to investigate any changes to the cholinergic neurons, vesicular glutamate transporter 1 and 2 proteins (VGLUT1 and VGLUT2), and glutamate decarboxylase (GAD) in the hippocampus. The results showed that AGE significantly improved the working memory and tended to improve the reference memory in cognitively-impaired rats. In addition, AGE significantly ameliorated the loss of cholinergic neurons and increased the VGLUT1 and GAD levels in the hippocampus of rat brains with Aß-induced toxicity. In contrast, the VGLUT2 protein levels did not change in any of the treated groups. We concluded that AGE was able to attenuate the impairment of working memory via the modification of cholinergic neurons, VGLUT1, and GAD in the hippocampus of Aß-induced rats.

Neuroprotective Effects of Aged Garlic Extract on Cognitive Dysfunction and Neuroinflammation Induced by ß-Amyloid in Rats.

Neuroinflammation is pathological evidence of Alzheimer's disease (AD) that likely starts as a host defense response to the damaging effects of the ß-amyloid (Aß) deposits in the brain. The activation of microglia may promote the neurodegenerative process through the release of proinflammatory cytokines, such as interleukin-1ß (IL-1ß) and tumor necrosis factor-α (TNFα), which may lead to neuronal damage and eventual death. Aged garlic extract (AGE) has been reported to have multiple biological activities, including anti-inflammatory effects. Therefore, the objective of this study was to investigate the effect of AGE on Aß (1-42)-induced cognitive dysfunction and neuroinflammation. Adult male Wistar rats were given AGE (125, 250, and 500 mg/kg BW, body weight), orally administered, daily for 56 days. They were then injected with 1 µL of aggregated Aß (1-42) into the lateral ventricles; bilaterally. Seven days later, their recognition memory was evaluated using a novel object recognition (NOR) test. Then the rats were sacrificed to investigate the alteration of microglia cells, IL-1ß and TNFα in the cerebral cortex and hippocampus. The results indicated that AGE at doses of 250 and 500 mg/kg BW significantly improved short-term recognition memory in cognitively impaired rats. In addition, AGE significantly minimized the inflammatory response by reducing the activation of microglia and IL-1ß to the levels found in the control, which is similar to the results found in Celebrex-treated rats. In conclusion, AGE may be useful for improving the short-term recognition memory and relieve the neuroinflammation in Aß-induced rats.