Acute EPA-induced learning and memory impairment in mice is prevented by DHA.

Eicosapentaenoic acid (EPA), an omega-3 fatty acid, has been widely used to prevent cardiovascular disease (CVD) and treat brain diseases alone or in combination with docosahexaenoic acid (DHA). However, the impact of EPA and DHA supplementation on normal cognitive function and the molecular targets of EPA and DHA are still unknown. We show that acute administration of EPA impairs learning and memory and hippocampal LTP in adult and prepubescent mice. Similar deficits are duplicated by endogenously elevating EPA in the hippocampus in the transgenic fat-1 mouse. Furthermore, the damaging effects of EPA are mediated through enhancing GABAergic transmission via the 5-HT6R. Interestingly, DHA can prevent EPA-induced impairments at a ratio of EPA to DHA similar to that in marine fish oil via the 5-HT2CR. We conclude that EPA exhibits an unexpected detrimental impact on cognitive functions, suggesting that caution must be exercised in omega-3 fatty acid supplementation and the combination of EPA and DHA at a natural ratio is critical for learning and memory and synaptic plasticity.

Ultrasound assisted extraction of polysaccharides from Lentinus edodes and its anti-hepatitis B activity in vitro.

The aim of this study was to optimize the extraction process of polysaccharides from the fruiting bodies of Lentinus edodes and investigate its anti-hepatitis B virus activity. The extracting parameters including ultrasonic power (240-320W), extraction temperature (40-60°C) and extraction time (15-25min) was optimized by using three-variable-three-level Box-Behnken design based on the single-factor experiments. Data analysis results showed that the optimal conditions for extracting LEPs were an extraction temperature of 45°C, extraction time of 21min and ultrasonic power of 290W. Under these optimal conditions, the experimental yield of LEPs was 9.75%, a 1.62-fold increase compared with conventional heat water extraction (HWE). In addition, crude polysaccharides were purified to obtain two fractions (LEP-1 and LEP-2). Chemical analysis showed that these components were rich in glucose, arabinose and mannose. Furthermore, HepG2.2.15 cells were used as in vitro models to evaluate their anti-hepatitis B virus (HBV) activity. The results suggest that LEPs possesses potent anti-HBV activity in vitro.

[Effects of Jiji decoction on the cognitive function and oxidative stress in mice with vascular dementia induced by cerebral ischemia/reperfusion].

OBJECTIVE: To determine the effects of Jiji decoction (Traditional Chinese Medicine) on the cognitive function and oxidative stress in mice with vascular dementia (VD) induced by cerebral ischemia/reperfusion. METHODS: Thirty-two mice were randomly divided into nonnal group (n = 8), sham group (operation, but no cerebral ischemia/reperfusi6n, n = 8), model group (vascular dementia model induced by cerebral ischemia/reperfusion, n = 8), and Jiji decoction-treated group (vascular dementia model plus treatment with Jiji decoction, n = 8). Fourteen days of treatment after operation, the cognitive behavior was measured in step-through test, spatial probe test and platform test. Afterwards, to assess the levels of oxidative stress, the activity of superoxide dismutase(SOD) and content of malonaldehyde (MDA) in brain of these mice were measured. RESULTS: Data from step-through test indicated that the escaping latency of Jiji decoction-treated group was prolonged and the error counts were decreased significantly ( P <0.01) compared with those of model group. Data from spatial probe test indicated that the time of entering darkroom, the time of climbing height and the time of entering bright room in Jiji decoction-treated group were shortened and the counts of climbing height were increased (P < 0.05-0.01) significantly compared with those of model group. Data from platform test showed that the escaping latency of Jiji decoction-treated group was prolonged significantly (P < 0.01) compared with that of model group. Compared with normal and sham group, the activity of SOD was decreased and the content of MDA was increased in model group significantly (P < 0.01). Compared with those of model group, the levels of SOD and MDA in Jiji decoction-treated group were improved significantly (P < 0.01). CONCLUSION: Jiji decoction could improve cognitive function of VD mice. Its mechanism might be related with the inhibition of oxidative stiess in the brain.

[Effect of Alternanthera philoxeroides on enzymic histochemistry of Oncomelania hupensis].

OBJECTIVE: To investigate the mechanisms of Alternanthera philoxeroides (Mardus) Grisebach in inhibiting Oncomelania snails' locomotivity and killing effect. METHODS: Uninfected snails were divided into four groups and exposed to an aqueous extract of A. philoxeroides and dechlorinated water (as control) for 12 h or 20 h, respectively. The activities of the Mg2+-adenosine triphosphatase (Mg2+-ATPase), cholinesterase (ChE), lactate dehydrogenase (LDH) and succinate dehydrogenase (SDH) in the head-foot muscles, centric ganglions, gills and liver of Oncomelania hupensis were analyzed using enzyme histochemistry technology and changes were observed under a light microscope. Statistical quantitative analysis of data of grey values was conducted on the computer-assisted image analyzing system (HPIAS-1000). RESULTS: The color of stained ChE in the head-foot muscles, centric ganglions and gills of the snail lightened evidently, showing a decrease of ChE activity after snails were immersed in the extract of A. philoxeroides for 12 h or 20 h. Results of grey values at different stained parts of snail, measured by the computer-assisted image analyzing system, indicated that there was a significant difference (P<0.01) between the activities of ChE in the head-foot muscles (130.95 +/- 8.08, 129.91 +/- 7.05), centric ganglions (127.43 +/- 7.27, 126.78 +/- 7.38) and gills (121.38 +/- 7.31, 126.41 +/- 8.28) from snails exposed to aqueous extract of A. philoxeroides for 12 h and 20 h and the activities of the enzyme in counter-parts (64.65 +/- 8.54, 65.18 +/- 7.96, 57.86 +/- 6.57, 50.71 +/- 6.15, 88.96 +/- 6.78 and 89.86 +/- 7.01, respectively) from control group. The activities of Mg2+-ATPase also showed a significant difference (P<0.05) in the head-foot muscles (89.91 +/- 5.08), centric ganglions (71.15 +/- 5.43) and liver (112.40 +/- 7.81) of the snail after 20 h of exposure against those in counter-parts (78.81 +/- 8.10, 60.09 +/- 6.05 and 95.50 +/- 8.35, respectively) from the control, but no significant difference (P>0.05) was shown on the activities of Mg2+-ATPase between the snails exposed for 12 h in extract of A. philoxeroides and those of control. No statistical difference (P>0.05) was found between the dechlorinated water group and the extract of A. philoxeroides group in the activities of LDH and SDH after 12 h or 20 h of exposure. CONCLUSION: The extract of A. philoxeroides rapidly inhibits ChE, and then the activity of Mg2+-ATPase, which may suppress the release and utilization of ATP in the Oncomelania snails and finally causes death of snails.

[Protective effects of liquid extract of Lishi No.5 formula against excitatory amino acid damage of neurons].

OBJECTIVE: To investigate the effect of liquid extract of Lishi No.5 formula in protecting the neurons from excitatory amino acid injury. METHODS: Cultured neonatal SD rat hippocampal neurons were treated with 300 micromol/L NMDA and 5 micromol/L glycine for 10 min, and the conditioned culture medium was replaced by normal culture medium. After cell culture for 18 h, MTT assay and Hoechst33258 staining were performed to examine the cell survival rate and cell apoptosis, respectively. Intracellular free calcium concentration was assayed by image analysis of the calcium signals with confocal microscope and Fluo-3/AM indicator. RESULTS: The survival rate of the cultured cell was significantly decreased in response to treatment with 300 micromol/L NMDA and 5 micromol/L glycine, but the effects were obviously reversed by treatment with 0.5 mg/ml liquid extract from Lishi No.5 formula. Intracellular free calcium concentration was significantly increased by 10 micromol/L NMDA, which was remarkably inhibited by the liquid extract. The effects of NMDA on intracellular free calcium was abolished by pretreatment of the cells with MK-801 for 10 min, whereas the liquid extract significantly lowered the antagonizing effect of MK-801. CONCLUSION: Lishi No.5 formula protects the neurons from toxicity by excitatory amino acids possibly by alleviating intracellular free calcium overload induced by these amino acids.

[Neuroprotective effects of Naoxintong against neuronal injury in hippocampal CA1 region following transient forebrain ischemia in rats].

OBJECTIVE: To examine the neuroprotective effects of Naoxintong and Zhongfenghuichunwan on neuronal injury in CA1 region of rat hippocampus following transient forebrain ischemia. METHODS: Transient rat forebrain ischemia for 15 min was induced by modified four-vessel occlusion method. The density of survived pyramidal cells (neurons per 1 mm linear length) in CA1 region of the hippocampus was measured under light microscope. RESULTS: In Naoxintong or nimodipine-treated rats, the density of survived pyramidal cells in CA1 region was significantly greater than that of saline group (P<0.05, P<0.001, respectively), but oral administration of Zhongfenghuichunwan had no obvious effect on ischemia-induced neuronal damage in CA1 region. CONCLUSION: Naoxintong can protect CA1 neurons against ischemic insult in rats.