ErbB3 is required for hyperaminoacidemia-induced pancreatic α cell hyperplasia.

Blood amino acid levels are maintained in a narrow physiological range. The pancreatic α cells have emerged as the primary aminoacidemia regulator through glucagon secretion to promote hepatic amino acid catabolism. Interruption of glucagon signaling disrupts the liver-α cells axis leading to hyperaminoacidemia, which triggers a compensatory rise in glucagon secretion and α cell hyperplasia. The mechanisms of hyperaminoacidemia-induced α cell hyperplasia remain incompletely understood. Using a mouse α cell line and in vivo studies in zebrafish and mice, we found that hyperaminoacidemia-induced α cell hyperplasia requires ErbB3 signaling. In addition to mechanistic target of rapamycin complex 1, another ErbB3 downstream effector signal transducer and activator of transcription 3 also plays a role in α cell hyperplasia. Mechanistically, ErbB3 may partner with ErbB2 to stimulate cyclin D2 and suppress p27 via mechanistic target of rapamycin complex 1 and signal transducer and activator of transcription 3. Our study identifies ErbB3 as a new regulator for hyperaminoacidemia-induced α cell proliferation and a critical component of the liver-α cells axis that regulates aminoacidemia.

The protective effect and mechanism of glycosides of cistanche deserticola on rats in middle cerebral artery occlusion (MCAO) model.

Cerebral ischemia-reperfusion injury (CIRI) occurs frequently clinically as a complication following cardiovascular resuscitation resulting in neuronal damage specifically to the hippocampal CA1 region with consequent cognitive impairment. Apoptosis and oxidative stress were proposed as major risk factors associated with CIRI development. Previously, glycosides obtained from Cistanche deserticola (CGs) were shown to play a key role in counteracting CIRI; however, the underlying mechanisms remain to be determined. This study aimed to investigate the neuroprotective effect of CGs on subsequent CIRI in rats. The model of CIRI was established for 2 hr and reperfusion for 24 hr by middle cerebral artery occlusion (MCAO) model. The MCAO rats were used to measure the antioxidant and anti-apoptotic effects of CGs on CIRI. Neurological function was evaluated by the Longa neurological function score test. 2,3,5-Triphenyltetrazolium chloride (TTC) staining was used to detect the area of cerebral infarction. Nissl staining was employed to observe neuronal morphology. TUNEL staining was used to detect neuronal apoptosis, while Western blot determined protein expression levels of factors for apoptosis-related and PI3K/AKT/Nrf2 signaling pathway. Data demonstrated that CGs treatment improved behavioral performance, brain injury, and enhanced antioxidant and anti-apoptosis in CIRI rats. In addition, CGs induced activation of PI3K/AKT/Nrf2 signaling pathway accompanied by inhibition of the expression of apoptosis-related factors. Evidence indicates that CGs amelioration of CIRI involves activation of the PI3K/AKT/Nrf2 signaling pathway associated with increased cellular viability suggesting these glycosides may be considered as an alternative compound for CIRI treatment.

Effect of total flavonoids of Dracocephalum moldavica L. On neuroinflammation in Alzheimer's disease model amyloid-ß (Aß1-42)-peptide-induced astrocyte activation.

One of the main pathological features noted in Alzheimer's disease (AD) is the presence of plagues of aggregated ß-amyloid (Aß1-42)-peptides. Excess deposition of amyloid-ß oligomers (AßO) are known to promote neuroinflammation. Sequentially, following neuroinflammation astrocytes become activated with cellular characteristics to initiate activated astrocytes. The purpose of this study was to determine whether total flavonoids derived from Dracocephalum moldavica L. (TFDM) inhibited Aß1-42-induced damage attributed to activated C8-D1A astrocytes. Western blotting and ELISA were used to determine the expression of glial fibrillary acidic protein (GFAP), and complement C3 to establish the activation status of astrocytes following induction from exposure to Aß1-42. Data demonstrated that stimulation of C8-D1A astrocytes by treatment with 40 µM Aß1-42 for 24 hr produced significant elevation in protein expression and protein levels of acidic protein (GFAP) and complement C3 accompanied by increased expression and levels of inflammatory cytokines. Treatment with TFDM or the clinically employed drug donepezil in AD therapy reduced production of inflammatory cytokines, and toxicity initiated following activation of C8-D1A astrocytes following exposure to Aß1-42. Therefore, TFDM similar to donepezil inhibited inflammatory secretion in reactive astrocytes, suggesting that TFDM may be considered as a potential compound to be utilized in AD therapy.

Cannabidiol improves the cognitive function of SAMP8 AD model mice involving the microbiota-gut-brain axis.

Cannabidiol (CBD), a natural component extracted from Cannabis sativa L. exerts neuroprotective, antioxidant, and anti-inflammatory effects in Alzheimer's disease (AD), a disease characterized by impaired cognition and accumulation of amyloid-B peptides (Aß). Interactions between the gut and central nervous system (microbiota-gut-brain axis) play a critical role in the pathogenesis of neurodegenerative disorder AD. At present investigations into the mechanisms underlying the neuroprotective action of CBD in AD are not conclusive. The aim of this study was thus to examine the influence of CBD on cognition and involvement of the microbiota-gut-brain axis using a senescence-accelerated mouse prone 8 (SAMP8) model. Data demonstrated that administration of CBD to SAMP8 mice improved cognitive function as evidenced from the Morris water maze test and increased hippocampal activated microglia shift from M1 to M2. In addition, CBD elevated levels of Bacteriodetes associated with a fall in Firmicutes providing morphologically a protective intestinal barrier which subsequently reduced leakage of intestinal toxic metabolites. Further, CBD was found to reduce the levels of hippocampal and colon epithelial cells lipopolysaccharide (LPS), known to be increased in AD leading to impaired gastrointestinal motility, thereby promoting neuroinflammation and subsequent neuronal death. Our findings demonstrated that CBD may be considered a beneficial therapeutic drug to counteract AD-mediated cognitive impairment and restore gut microbial functions associated with the observed neuroprotective mechanisms.

Effects of schisandrin B on hypoxia-related cognitive function and protein expression in vascular dementia rats.

Vascular dementia (VD) a heterogenous group of brain disorders in which cognitive impairment is attributable to vascular risk factors and cerebrovascular disease. A common phenomenon in VD is a dysfunctional cerebral regulatory mechanism associated with insufficient cerebral blood flow, ischemia and hypoxia. Under hypoxic conditions oxygen supply to the brain results in neuronal death leading to neurodegenerative diseases including Alzheimer's (AD) and VD. In conditions of hypoxia and low oxygen perfusion, expression of hypoxia-inducible factor 1 alpha (HIF-1α) increases under conditions of low oxygen and low perfusion associated with upregulation of expression of hypoxia-upregulated mitochondrial movement regulator (HUMMR), which promotes anterograde mitochondrial transport by binding with trafficking protein kinesin 2 (TRAK2). Schisandrin B (Sch B) an active component derived from Chinese herb Wuweizi prevented ß-amyloid protein induced morphological alterations and cell death using a SH-SY5Y neuronal cells considered an AD model. It was thus of interest to determine whether Sch B might also alleviate VD using a rat bilateral common carotid artery occlusion (BCAO) dementia model. The aim of this study was to examine the effects of Sch B in BCAO on cognitive functions such as Morris water maze test and underlying mechanisms involving expression of HIF-1α, TRAK2, and HUMMR levels. The results showed that Sch B improved learning and memory function of rats with VD and exerted a protective effect on the hippocampus by inhibition of protein expression of HIF-1α, TRAK2, and HUMMR factors. Evidence indicates that Sch B may be considered as an alternative in VD treatment.

Crispr-Cas9 mediated complete deletion of glucagon receptor in mice display hyperglucagonemia and α-cell hyperplasia.

Glucagon receptor plays an important role in the regulation of glucose metabolism. Studies have revealed that glucagon receptor antagonism is a potential effective treatment for diabetes. However, the functions of GCGR have not been fully illustrated. Although two Gcgr truncation knockout mice models have been widely used for GCGR function studies, truncated gene may remain neomorphic and/or dominant-negative function. In this study, we took the advantages of Crispr-Cas9 technique and generated a novel allele of GCGR in the mouse that yields complete loss of GCGR protein. Our studies reveal that complete deletion of Gcgr results in hyperglucagonemia, α-cell hyperplasia, improvement of glucose tolerance. These results are similar to the Gcgr-truncated mutation in mice. Hence, we provide a novel strain of GCGR knockout mice for the GCGR function studies.

Disruption of the glucagon receptor increases glucagon expression beyond α-cell hyperplasia in zebrafish.

The glucagon receptor (GCGR) is a potential target for diabetes therapy. Several emerging GCGR antagonism-based therapies are under preclinical and clinical development. However, GCGR antagonism, as well as genetically engineered GCGR deficiency in animal models, are accompanied by α-cell hyperplasia and hyperglucagonemia, which may limit the application of GCGR antagonism. To better understand the physiological changes in α cells following GCGR disruption, we performed single cell sequencing of α cells isolated from control and gcgr-/- (glucagon receptor deficient) zebrafish. Interestingly, beyond the α-cell hyperplasia, we also found that the expression of gcga, gcgb, pnoca, and several glucagon-regulatory transcription factors were dramatically increased in one cluster of gcgr-/- α cells. We further confirmed that glucagon mRNA was upregulated in gcgr-/- animals by in situ hybridization and that glucagon promoter activity was increased in gcgr-/-;Tg(gcga:GFP) reporter zebrafish. We also demonstrated that gcgr-/- α cells had increased glucagon protein levels and increased granules after GCGR disruption. Intriguingly, the increased mRNA and protein levels could be suppressed by treatment with high-level glucose or knockdown of the pnoca gene. In conclusion, these data demonstrated that GCGR deficiency not only induced α-cell hyperplasia but also increased glucagon expression in α cells, findings which provide more information about physiological changes in α-cells when the GCGR is disrupted.

Novel Loss-of-Function Variant in HNF1a Induces ß-Cell Dysfunction through Endoplasmic Reticulum Stress.

Heterozygous variants in the hepatocyte nuclear factor 1a (HNF1a) cause MODY3 (maturity-onset diabetes of the young, type 3). In this study, we found a case of novel HNF1a p.Gln125* (HNF1a-Q125ter) variant clinically. However, the molecular mechanism linking the new HNF1a variant to impaired islet ß-cell function remains unclear. Firstly, a similar HNF1a-Q125ter variant in zebrafish (hnf1a+/-) was generated by CRISPR/Cas9. We further crossed hnf1a+/- with several zebrafish reporter lines to investigate pancreatic ß-cell function. Next, we introduced HNF1a-Q125ter and HNF1a shRNA plasmids into the Ins-1 cell line and elucidated the molecular mechanism. hnf1a+/- zebrafish significantly decreased the ß-cell number, insulin expression, and secretion. Moreover, ß cells in hnf1a+/- dilated ER lumen and increased the levels of ER stress markers. Similar ER-stress phenomena were observed in an HNF1a-Q125ter-transfected Ins-1 cell. Follow-up investigations demonstrated that HNF1a-Q125ter induced ER stress through activating the PERK/eIF2a/ATF4 signaling pathway. Our study found a novel loss-of-function HNF1a-Q125ter variant which induced ß-cell dysfunction by activating ER stress via the PERK/eIF2a/ATF4 signaling pathway.

Ag metal interconnect wires formed by pseudoplastic nanoparticles fluid imprinting lithography with microwave assistant sintering.

Nanoimprint technology has the advantages of low cost, high precision, high fidelity and high yield. The metal nanoparticle fluid is non-Newtonian fluid, which is used as the imprint transfer medium to realize high fidelity of pattern because of its shear thinning effect. In order to functionalize the metal nanoparticles microstructure, the subsequent sintering step is required to form a metal interconnect wire. Metal interconnect wire with fewer grain boundaries and fewer holes have excellent mechanical and electronic properties. In this paper, the pseudoplastic metal nanoparticle fluid was formed by Ag nanoparticle and precursor solution, and then the thermal diffusion process was completed by microwave sintering after interconnects were embossed. The influence of microwave and thermal atmosphere on the microstructure and performance of Ag Interconnect wires was analyzed and discussed, and the Ag Interconnect wires performance was determined under the influence of time and temperature parameters. In our experiments, the interconnects after microwave sintering can achieve 39% of the conductivity of bulk silver. The microwave sintering module might be integrated as the heat treatment module of the metal micro/nano pattern directly imprint lithography.

Mid-long wavelength infrared absorptance of hyperdoped silicon via femtosecond laser microstructuring.

Hyperdoped silicon (hSi) fabricated via femtosecond laser irradiation has emerged as a promising photoelectric material with strong broadband infrared (IR) absorption. In this work, we measured the optical absorptance of the hSi in the wavelength of 0.3-16.7 µm. Unlike the near to mid wavelength IR absorption, the mid-long wavelength IR (M-LWIR) absorption is heavily dependent on the surface morphology and the dopants. Furthermore, calculations based on coherent potential approximation (CPA) reveal the origin of free carrier absorption, which plays an important role in the M-LWIR absorption. As a result, a more comprehensive picture of the IR absorption mechanism is drawn for the optoelectronic applications of the hSi.

Artemether and aspterric acid induce pancreatic alpha cells to transdifferentiate into beta cells in zebrafish.

BACKGROUND AND PURPOSE: Recently, the antimalarial drug, artemether and the neurotransmitter GABA were identified to convert alpha cells into beta-like cells in vivo. However, some of these observations were challenged by other studies. To help address the controversy, we took advantage of zebrafish as a model to perform this study. EXPERIMENTAL APPROACH: First, we performed a small-molecule screening for artemether and its skeleton analogues. Second, we used the Cre-LoxP system for lineage tracing to indicate the conversion of alpha cells into beta cells in vivo. The stable transgenic ins2:eGFP αTC1-6-cell line was used for evaluation of alpha-cell transdifferentiation in vitro. We further used multiple zebrafish transgenic and mutation lines to demonstrate beta-cell differentiation, beta-cell ablation and alpha-cell hyperplasia in this study. KEY RESULTS: We showed that artemether and another sesquiterpene, aspterric acid, induced alpha-cell transdifferentiation into beta cells, both in zebrafish as well as using αTC1-6 cells. Furthermore, these two compounds also converted alpha cells into beta cells when beta cells were lost or alpha cells were hyperplastic in zebrafish. Unlike the previous report, the conversion of alpha cells to beta cells was mediated by increasing Pax4 expression, but not suppression of Arx expression. CONCLUSION AND IMPLICATIONS: Our data suggest that in zebrafish and αTC1-6 cells, both artemether and aspterric acid induce alpha-cell transdifferentiation. Our data, along with those of Li et al. (2017), suggested that artemether and aspterric acid were able to induce alpha-cell transdifferentiation, at least in zebrafish and αTC1-6 cells.

Two new compounds from a mangrove sediment-derived fungus Penicillium polonicum H175.

Two new compounds, 6-acetyl-4-methoxy-3,5-dimethyl-2H-pyran-2-one (1) and (2E,4E)-5-((2S,3S,4R,5R)-3,4-dihydroxy-2,4,5-trimethyltetrahydrofuran-2-yl)-2,4-dimethylpenta-2,4-dienal (2), and 22 known compounds were identified from the mangrove-forest-derived fungus Penicillium polonicum H175. The structures of these compounds were elucidated by analysis of the high-resolution electrospray ionisation mass spectroscopy (HR-ESI-MS), 1 D and 2 D nuclear magnetic resonance (NMR) data. The hypoglycaemic effect of compounds was evaluated by the Tg (Ins: htBidTE-ON; LR) zebrafish model. Compound 3 (aspterric acid) exhibited a significant hypoglycaemic effect equivalent to the positive drug rosiglitazone (RSG) at 10 µmol/L.

Global Transcriptomic Analysis of Zebrafish Glucagon Receptor Mutant Reveals Its Regulated Metabolic Network.

The glucagon receptor (GCGR) is a G-protein-coupled receptor (GPCR) that mediates the activity of glucagon. Disruption of GCGR results in many metabolic alterations, including increased glucose tolerance, decreased adiposity, hypoglycemia, and pancreatic α-cell hyperplasia. To better understand the global transcriptomic changes resulting from GCGR deficiency, we performed whole-organism RNA sequencing analysis in wild type and gcgr-deficient zebrafish. We found that the expression of 1645 genes changes more than two-fold among mutants. Most of these genes are related to metabolism of carbohydrates, lipids, and amino acids. Genes related to fatty acid ß-oxidation, amino acid catabolism, and ureagenesis are often downregulated. Among gcrgr-deficient zebrafish, we experimentally confirmed increases in lipid accumulation in the liver and whole-body glucose uptake, as well as a modest decrease in total amino acid content. These results provide new information about the global metabolic network that GCGR signaling regulates in addition to a better understanding of the receptor's physiological functions.

Integrated Metabolomics and Lipidomics Analysis Reveal Remodeling of Lipid Metabolism and Amino Acid Metabolism in Glucagon Receptor-Deficient Zebrafish.

The glucagon receptor (GCGR) is activated by glucagon and is essential for glucose, amino acid, and lipid metabolism of animals. GCGR blockade has been demonstrated to induce hypoglycemia, hyperaminoacidemia, hyperglucagonemia, decreased adiposity, hepatosteatosis, and pancreatic α cells hyperplasia in organisms. However, the mechanism of how GCGR regulates these physiological functions is not yet very clear. In our previous study, we revealed that GCGR regulated metabolic network at transcriptional level by RNA-seq using GCGR mutant zebrafish (gcgr -/-). Here, we further performed whole-organism metabolomics and lipidomics profiling on wild-type and gcgr -/- zebrafish to study the changes of metabolites. We found 107 significantly different metabolites from metabolomics analysis and 87 significantly different lipids from lipidomics analysis. Chemical substance classification and pathway analysis integrated with transcriptomics data both revealed that amino acid metabolism and lipid metabolism were remodeled in gcgr-deficient zebrafish. Similar to other studies, our study showed that gcgr -/- zebrafish exhibited decreased ureagenesis and impaired cholesterol metabolism. More interestingly, we found that the glycerophospholipid metabolism was disrupted, the arachidonic acid metabolism was up-regulated, and the tryptophan metabolism pathway was down-regulated in gcgr -/- zebrafish. Based on the omics data, we further validated our findings by revealing that gcgr -/- zebrafish exhibited dampened melatonin diel rhythmicity and increased locomotor activity. These global omics data provide us a better understanding about the role of GCGR in regulating metabolic network and new insight into GCGR physiological functions.

Inhibition of oxidative stress by testosterone improves synaptic plasticity in senescence accelerated mice.

It is well known that synaptic plasticity is associated with cognitive performance in Alzheimer's disease (AD). Testosterone (T) is known to exert protective effects on cognitive deficits in AD, but the underlying mechanisms of androgenic action on synaptic plasticity remain unclear. Thus, the aim of this study was to examine the protective mechanism attributed to T on synaptic plasticity in an AD senescence accelerated mouse prone 8 (SAMP8) model. The following parameters were measured: (1) number of intact pyramidal cells in hippocampal CA1 region (2) phosphorylated N-methyl-D-aspartate receptor-1 (p-NMDAR1) and (3) phosphorylated calmodulin-dependent protein kinase II (p-CaMKII). In addition, the content of whole brain malondialdehyde (MDA) as well as activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were determined. Treatment with T significantly elevated the number of intact pyramidal cells in hippocampal CA1 region and markedly increased hippocampal protein and mRNA expression levels of p-NMDAR1 and p-CaMK II. Further, T significantly decreased whole brain MDA levels accompanied by elevated activities of SOD and GSH-Px. Data suggest that the protective effects of T on synaptic plasticity in a mouse AD model may be associated with reduction of oxidant stress.

The protective mechanisms underlying Ginsenoside Rg1 effects on rat sciatic nerve injury.

Ginsenoside Rg1 (GsRg1), derived from the herb Ginseng, was found to exert protective effects in nerve injury; however, the mechanisms underlying these effects remain to be determined. Oxidant stress and apoptosis are known to be involved in sciatic nerve injury. Thus, the aim of this study was to examine whether GsRg1 was able to modify sciatic nerve injury in a rat model. The following parameters were measured: (1) number of spinal cord motoneurons by Nissl staining, (2) oxidation parameters including spinal cord malondialdehyde (MDA) levels and activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) as well as (3) involvement of apoptosis by determining caspase-3 and X-linked inhibitor of apoptosis protein (XIAP) by immunohistochemistry and Western blot. The number of spinal cord motoneurons was significantly reduced after sciatic nerve injury, while treatment with GsRg1 markedly elevated cell number. Sciatic nerve injury markedly increased spinal cord MDA content concomitant with reduced activities of SOD and GSH-Px. GsRg1 significantly decreased MDA content accompanied by elevated activities of SOD and GSH-Px. Further nerve injury significantly diminished protein expression levels of XIAP accompanied by elevated protein expression levels of caspase-3 in the spinal cord. GsRg1 markedly increased protein expression levels of XIAP, but significantly reduced protein expression levels of caspase-3. Data suggest that the protective effects of GsRg1 in sciatic nerve injury may be associated with reduced oxidative stress involving anti-apoptotic pathways.

Mechanisms Associated with Protective Effects of Ginkgo Biloba Leaf Extracton in Rat Cerebral Ischemia Reperfusion Injury.

Cerebral infarction occurs as a consequence of cerebral ischemia-reperfusion injury (CIRI). Ginkgo biloba leaf extract (GbE) is composed predominantly of active ingredients such as flavonoids and terpene lactones and often used to treat cerebrovascular diseases. However, the mechanisms underlying the use of this herbal extract to treat cerebrovascular-mediated damage are not known. The aim of this study was to examine the effectiveness of administration GbE to ameliorate the observed consequences of CIRI. The following parameters were measured: (1) behavioral score (2) infarct area (3) the content of serum malondialdehyde (MDA) as well as activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and (4) interleukin 6 (IL-6) and tumor necrosis factor-alpha (TNF-α) expression levels in the infarcted brain tissue. Data demonstrated that treatment with GbE to CIRI rats resulted in significant reduction in cerebral-infarcted area associated with improvement in behavioral score. GbE was found to decrease serum MDA levels concomitant with elevated activity levels of SOD and GSH-PX. Immunohistochemistry and Western blot analysis showed that GbE significantly lowered the levels of IL-6 and TNF-α in the infarcted brain tissue. Data suggest that GbE may be therapeutically effective in improving behavioral score in CIRI rats through reduction of oxidative stress and anti-inflammation in the cerebral infarction region.

Involvement of apoptosis in the protective effects of Dracocephalum moldavaica in cerebral ischemia reperfusion rat model.

An extract of Dracocephalum moldevica (DML) was found to exert protective effects on cerebral ischemia-reperfusion injury (CIRI); however, the mechanisms underlying the observed actions of this plant-derived mixture remain to be determined. Thus, the aim of this study was to examine the influence of DML on CIRI rat model induced by middle cerebral artery occlusion (MCAO). The following parameters were measured: (1) viable neurons in the infarcted area using Nissl staining; and (2) immunohistochemistry and Western blot were employed to determine protein expression levels of p53, bcl-2 associated X protein (bax) and B-cell lymphoma-2 (bcl-2), three biomarkers of apoptosis. MCAO significantly decreased the number of viable cortical pyramidal neurons in the infarcted area, while treatment with DML extract significantly elevated the number of viable neurons. MCAO was found to significantly elevate in gene expression levels of p53 and protein expression levels bax accompanied by diminished protein expression levels of bcl-2. Prior administration of DML extract produced marked reduction in gene expression levels of p53 and protein expression levels bax but increased in protein expression levels of bcl-2. Data suggested apoptosis was initiated in MCAO and that DML was effective in treating CIRI via an anti-apoptotic action as evidenced by inhibition of gene expression levels of p53 and protein expression levels of bax with concomitant elevation in protein expression levels of bcl-2. Our findings suggest that extract of DML may prove beneficial in treatment of cerebrovascular disorders.

Protective mechanism of testosterone on cognitive impairment in a rat model of Alzheimer's disease.

Cognitive dysfunction in Alzheimer's disease is strongly associated with a reduction in synaptic plasticity, which may be induced by oxidative stress. Testosterone is beneficial in learning and memory, although the underlying protective mechanism of testosterone on cognitive performance remains unclear. This study explored the protective mechanism of a subcutaneous injection of 0.75 mg testosterone on cognitive dysfunction induced by bilateral injections of amyloid beta 1-42 oligomers into the lateral ventricles of male rats. Morris water maze test results demonstrated that testosterone treatment remarkably reduced escape latency and path length in Alzheimer's disease rat models. During probe trials, testosterone administration significantly elevated the percentage of time spent in the target quadrant and the number of platform crossings. However, flutamide, an androgen receptor antagonist, inhibited the protective effect of testosterone on cognitive performance in Alzheimer's disease rat models. Nissl staining, immunohistochemistry, western blot assay, and enzyme-linked immunosorbent assay results showed that the number of intact hippocampal pyramidal cells, the dendritic spine density in the hippocampal CA1 region, the immune response and expression level of postsynaptic density protein 95 in the hippocampus, and the activities of superoxide dismutase and glutathione peroxidase were increased with testosterone treatment. In contrast, testosterone treatment reduced malondialdehyde levels. Flutamide inhibited the effects of testosterone on all of these indicators. Our data showed that the protective effect of testosterone on cognitive dysfunction in Alzheimer's disease is mediated via androgen receptors to scavenge free radicals, thereby enhancing synaptic plasticity.

The protective mechanism underlying total flavones of Dracocephalum (TFD) effects on rat cerebral ischemia reperfusion injury.

Previously, total flavones of Dracocephalum (TFD), derived from Dracocephalum, were found to exert protective effects in cerebral ischemia reperfusion injury (CIRI) in middle cerebral artery occlusion (MCAO) rat model. However, the mechanisms underlying these observed effects of TFD on MCAO-induced rats still remain to be determined. Therefore, the aim of this study was to examine whether TFD alleviated MCAO through mechanisms involving anti-inflammatory and anti-apoptotic using MCAO rats. The following parameters were measured: (1) percentage (%) area of brain infarction; (2) serum levels of inflammatory cytokines, including tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) and (3) expression protein levels of caspase-3 and AMP-activated protein kinase (AMPK). Results showed that MCAO significantly increased the % area of brain infarction, while TFD administration in these animals markedly reduced % area of brain infarction. A significant elevation on serum levels of TNF-α and IL-6 was noted with MCAO which was markedly reduced by TFD. In addition, MCAO produced a significant rise in protein expression levels of caspase-3 and AMPK. In contrast, TFD markedly lowered protein expression levels of caspase-3 and AMPK. Data suggest that the protective effects of TFD in MCAO model animals may involve inhibition of inflammatory mediator release associated with apoptosis through down regulation of AMPK signaling pathway.