Eleutheroside B or E enhances learning and memory in experimentally aged rats

Eleutheroside B or E, the main component of Acanthopanax, can relieve fatigue, enhance memory, and improve human cognition. Numerous studies have confirmed that high doses of acetylcholine significantly attenuate clinical symptoms and delay the progression of Alzheimer＇s disease. The present study replicated a rat model of aging induced by injecting quinolinic acid into the hippocampal CA1 region. These rats were intraperitoneally injected with low, medium and high doses of eleutheroside B or E （50, 100, 200 mg/kg）, and rats injected with Huperzine A or PBS were used as controls. At 4 weeks after administration, behavioral tests showed that the escape latencies and errors in searching for the platform in a Morris water maze were dose-dependently reduced in rats treated with medium and high-dose eleutheroside B or E. Hematoxylin-eosin staining showed that the number of surviving hippocampal neurons was greater and pathological injury was milder in three eleutheroside B or E groups compared with model group. Hippocampal homogenates showed enhanced cholinesterase activity, and dose-dependent increases in acetylcholine content and decreases in choline content following eleutheroside B or E treatment, similar to those seen in the Huperzine A group. These findings indicate that eleutheroside B or E improves learning and memory in aged rats. These effects of eleutheroside B or E may be mediated by activation of cholinesterase or enhanced reuse of choline to accelerate the synthesis of acetylcholine in hippocampal neurons.

Neuroprotective effect of Shenqi Fuzheng injection pretreatment in aged rats with cerebral ischemia/reperfusion injury

Shenqi Fuzheng injection is extracted from the Chinese herbs Radix Astragali and Radix Codonopsis. The aim of the present study was to investigate the neuroprotective effects of Shenqi Fuzheng injection in cerebral ischemia and reperfusion. Aged rats（20–22 months） were divided into three groups： sham, model, and treatment. Shenqi Fuzheng injection or saline（40 m L/kg） was injected into the tail vein daily for 1 week, after which a cerebral ischemia/reperfusion injury model was established. Compared with model rats that received saline, rats in the treatment group had smaller infarct volumes, lower brain water and malondialdehyde content, lower brain Ca2＋ levels, lower activities of serum lactate dehydrogenase and creatine kinase, and higher superoxide dismutase activity. In addition, the treatment group showed less damage to the brain tissue ultrastructure and better neurological function. Our findings indicate that Shenqi Fuzheng injection exerts neuroprotective effects in aged rats with cerebral ischemia/reperfusion injury, and that the underlying mechanism relies on oxygen free radical scavenging and inhibition of brain Ca2＋ accumulation.

Changes in intracellular calcium in brain cells of aged rats

BACKGROUND： Studies have shown that voltage-dependent calcium influx, and enhancement of certain calcium-dependent processes in neurons, is related to aging. OBJECTIVE： To observe changes in intracellular calcium （[Ca^2＋]i） in neurons of aged rats, and to compare with young rats. DESIGN, TIME AND SETTING： A randomized control experiment of neurophysiology was performed at the Central Laboratory of School of Pharmaceutical Science, China Medical University from June to August 2004. MATERIALS： Ten male, healthy, Wistar rats, 19 months old, were selected for the aged group. Ten male, 3-month-old, Wistar rats were selected for the young control group. Fura-2/AM was provided by the Institute of Pharmaceutical Research of Chinese Academy of Medical Sciences, and the F-2000 fluorospectrophotometer was a product of Hitachi, Japan. METHODS： Fluorescence Fura-2 spectrophotometer was used to measure [Ca^2＋]i in acutely dissociated brain cells of aged and young rats. The concentration of extracellular potassium was controlled by adding different volumes of chloridated potassium solution of high concentration. MAIN OUTCOME MEASURES： [Ca^2＋]i in neurons of young and aged rats in the presence of I mmol/L extracellular calcium concentration and 0 mmol/L （resting state）, 5, 10, 20, and 40 mmol/L extracellular potassium. Absolute increase of [Ca^2＋]i in neurons of young and aged rats when extracellular potassium was 5, 10, 20, 40 mmol/L. RESULTS： In the presence of 1 mmol/L extracellular Ca〉 and 0 mmol/L （resting state）, 5, 10, 20, and 40 mmol/L extracellular potassium, [Ca^2＋]i in the neurons of aged rats was significantly less than that in young rats （P 〈 0.05）. However, there was no significant difference in absolute [Ca^2＋]i increase induced by different concentrations of KCI between the aged and the young rats （P 〉 0.05）. CONCLUSION： The overload of [Ca^2＋]i in neurons of aged rats is greater than that of young rats under the same circumstances.

Correlation Analysis Between BDNF and Postoperative Cognitive Dysfunction in Aged Rats

Objective:To investigate the relationship between BDNF and postoperative cognitive dysfunction among aged rats.Methods:36 SPF healthy aged male SD rats were randomly assigned to a control group and a model group,respectively,with 18 rats in each group.Abdominal exploration was performed on the rats in the model group after anesthesia,while the rats in the control group were not operated on after anesthesia.The escape latency and swimming distance of the two groups were analyzed on a day prior to surgery as well as on the first day,third day,and seventh day following surgery;the expression levels of BDNF protein in the hippocampus of rats in the two groups were compared on the first day,third day,and seventh day following surgery;the correlation between BDNF and escape latency and swimming distance was analyzed.Results:The escape latency and swimming distance of the rats in the control group on a day prior to surgery,the first day,third day,and seventh day following surgery did not differ significantly(p>0.05),but those in the model group had significant behavioral difference(p<0.05).On a day prior to surgery,the rats in both groups showed no significant behavioral difference in escape latency and swimming distance(p>0.05),but on the first day,third day,and seventh day following surgery,the escape latency and swimming distance of the rats in the model group were significantly longer than those in the control group(p<0.05).In the control group,there was no significant difference in the protein expression of BDNF in the hippocampus of rats on the first day,third day,and seventh day following surgery,but there was significant difference in the model group.On the first day,third day,and seventh day following surgery,the BDNF protein expression level in the rats’hippocampus of the control group was significantly higher than that of the model group(p<0.05).The data from Pearson correlation analysis confirmed that BDNF protein expression is negatively correlated with escape latency(r=-0.567,p<0.001)and swimming distance(r=-0.623,p<0.001).Conclusion:In aged rats,the BDNF protein expression level decreases,and the degree of cognitive dysfunction increases after surgery.

Effects of Different Doses of BDNF on Postoperative Cognitive Function in Aged Rats Undergoing Abdominal Surgery

Objective:To investigate the effects of different doses of BDNF on postoperative cognitive function in aged rats undergoing abdominal surgery.Methods:72 aged healthy male SD rats of SPF grade were selected.According to the random number table method,the rats were randomly divided into the control group,model group,low dose BDNF injection group,and high dose BDNF injection group,with 18 rats in each group.The model group,low dose group,and high dose group underwent abdominal surgery after anesthesia,and 5μL/time of BDNF was intranasally administered to the rats in the low dose and high dose groups 6 hours after abdominal surgery,of which the dose of the low dose group was 0.1 g/L,while that of the high dose group was 0.2 g/L.The drug was administered alternately through both nostrils,with an interval of 2 minutes each time,for 5 times.The control group did not undergo surgery after anesthesia.The escape latency and swimming distance of the four groups of rats were compared before surgery,the first day,the third day,and the seventh day after surgery;similarly,the BDNF protein expression level in the hippocampus of the four groups of rats was compared on the first day,the third day,and the seventh day after surgery.Results:The escape latency and swimming distance of the control group were not statistically significant on the first day,the third day,and the seventh day after surgery,p>0.05;the escape latency and swimming distance of the model group,low dose group,and high dose group on the first day,the third day,and the seventh day after surgery were statistically significant,p<0.05.Before surgery,the escape latency and swimming distance of the four groups were not statistically significant,p>0.05;on the first day,the third day,and the seventh day after surgery,the escape latency and swimming distance of the model group>low dose group>high dose group>control group,p<0.05.The BDNF protein expression level in the hippocampus of the control group on the first day,the third day,and the seventh day after surgery showed no statistical significance p>0.05;the expression level of BDNF protein in the hippocampus of the model group,low dose group,and high dose group on the first day,the third day,and the seventh day after surgery was statistically significant,p<0.05.On the first day,the third day,and the seventh day after surgery,the expression level of BDNF protein in the hippocampus of the model group<low dose group<high dose group<control group,p<0.05.Conclusion:Compared with 0.1 g/L of BDNF,0.2 g/L of BDNF can improve the postoperative cognitive function of aged rats undergoing abdominal surgery.

Influence of ginsenoside on expression of brain-derived neurotrophic factor and receptor tyrosine kinase B in the medial septum of aged rats

BACKGROUND： It has beenshown that ginsenoside, the effective component of ginseng, can enhance expression of choline acetyl transferase, as well as brain-derived neurotrophic factor （BDNF） and its receptor tyrosine kinase B （TrkB）, in cholinergic neurons of the basal forebrain. OBJECTIVE： To qualitatively and quantitatively verify the influence of ginsenoside on expression of BDNF and its receptor, TrkB, in the medial septum of aged rats, and to provide a molecular basis for clinical application. DESIGN~ TIME AND SETTING： A contrast study, which was performed in the Department of Anatomy, China Medical University, and the Department of Anatomy, Shenyang Medical College between December 2005 and May 2007. MATERIALS： Thirty-five, healthy, female, Sprague Dawley rats were selected for this study. Ginsenoside （81% purity） was provided by Jilin Ji＇an Wantai Chinese Medicine Factory; anti-BDNF antibody, anti-TrkB antibody, and their kits were provided by Wuhan Boster Company. METHODS： A total of 35 rats were divided into three groups： young （four months old）, aging （26 months old）, and ginsenoside. Rats in the ginsenoside group were administered ginsenoside （25 mg/kg/d） between 17 months and 26 months. MAIN OUTCOME MEASURES： Immunohistochemistry and in situ hybridization were used to measure expression of BDNF and TrkB in the medial septum of aged rats, and the detected results were expressed as gray values. RESULTS： （1） Qualitative detection： using microscopy, degenerative neurons were visible in the medial septum in the aging group. However, neuronal morphology in the ginsenoside group was similar to neurons in the young group. （2） Quantitative detection： the mean gray value of BDNF-positive and TrkB-positive products in the aging group were significantly higher than in the young group （t = 3.346, 4.169, P 〈 0.01）; however, the mean gray value in the ginsenoside group was significantly lower than in the aging group （t = 2.432, 2.651, P 〈 0.01）. CONCLUSION： Ginsenoside can increase expression of BDNF and TrkB in the medial septum and delay the natural degeneration in aged rats.

Effect of Total Saponins of Ginseng Leaves on Immunity in Aged Rats

Objective: To explore the effect of total saponins of Ginseng leaves(GS) on the functions ofneutrophil and lymphocyte in the aged rats of 20 months. Methods: Three groups of aged rats were injected intraperiton-eally with doses of 12. 5 mg/kg, 25 kg/mg and 50 mg/kg of GS once daily for 3 days, the declinedimmunity of spleen lymphocytes (proliferation of spleen lymphocyte, phagocytosis), superoxide anion and nitricoxide formation were studied and were compared with those of young rats (2 months). Results: The declinedimmunity of spleen lymphocytes were improved dose-dependently after GS injected. Conclusion: The results indicate that GS may enhance neutrophil and lymphocyte mediated non--specific and specific defense function inaged rats.

Effects of Mulberry Extract on Regulation of Sex Hormone and Hypothalamic Neurotransmitter in Naturally Aged Female Rats

[Objective] This study aimed to investigate the effects of different mulberry extracts on sex hormone and hypothalamic neurotransmitter in naturally aged female rats and reveal the mechanism and material basis of anti-aging effect of mulberry. [ Method] Fourteen-month-old SD female rats were selected and ran- domly divided into model group, positive control group, high-dose and low-dose water extract groups, high-dose and low-dose 50% ethanol extract groups, and high-dose and low-dose 95% ethanol extract groups; four-month-old SD female rats were used as blank control group. After eight weeks of drug administration, the levels of 17β-estradiol （E2 ）, follicle- stimulating hormone （FSH） and luteinizing hormone （LH） in serum and beta-endorphin （β-EP） in hypothalamus were de- termined by radioimmunoassay; the levels of norepinephrine （ NE）, dopamine （ DA）, 5-hydroxy tryptamine （5-HT） and 5-HIAA in hypothalamus were determined by fluorescence spectrometry. [ Result] Water extract of mulberry can increase the level of E2 and reduce levels of FSH and LH in serum, and increase the level of fl-EP and reduce levels of DA, 5-HT and 5-HIAA in hypothalamus of naturally aged female rats. Water extract of mulberry exhibited higher effects than 50% eth- anol extract and 95% ethanol extract. [ Conclusion] Mulberry could significantly improve the function of hypothalamic peptide neurotransmitter in naturally aged rats, correct disorders of hypothalamic monoamine neurotransmitter, and treat perimenopausal syndrome by regulating reproductive endocrine function, which might be related with its water-soluble components and require further investigation and development.

Effects of Herba Epimedii and Fructus Ligustri lucidi on the Transcription Factors in Hypothalamus of Aged Rats

Objective： To comparatively analyze the difference in the expression of 54 transcription factors in the hypothalamus using protein chips following the medication of Chinese drugs for Shen （肾）-tonification, Herba Epimedii, and Fructus Ligustri lucidi （FL） to aged rats. Methods： Wistar rats, aged 15 months of SPF grade, were randomized into three groups, three males and three females in each group. They were medicated with Herba Epimedii decoction （HED, 0.14 g/kg）, Fructus Ligustri lucidi decoction （FLD, 0.12 g/kg）, and distilled water, respectively, twice a day for 15 days. The rats were sacrificed at the morning of the 16th day 1 h after medication, and their hypothalamus was taken and made into homogenate under an ice-bath for detecting the expression of transcription factors with chip technique. Results： The expressions of signal transduction and transcription activation factor-6 （Stat-6） and androgen receptor （AR） were up-regulated, and those of pre-B transcription factor1 （Pbx-1）, stat-1 and AP-2 were down-regulated in both HED and FLD treated groups, but these changes occurred mainly in female rats in the former while mainly in males in the latter. Conclusions： Chinese drugs for Shen-tonification could impact the expression of transcription factors in the hypothalamus of aged rats, dominantly on the neuro-endocrine factors responsible for the growth and development. The effects of drugs for tonifying Shen-yang and for tonifying Shen-yin are different, which is probably one of the pharmacological mechanisms of the Shen-tonifying drugs.

Analysis of transcriptome sequencing of sciatic nerves in Sprague-Dawley rats of different ages

An aging-induced decrease in Schwann cell viability can affect regeneration following peripheral nerve injury in mammals. It is therefore necessary to investigate possible age-related changes in gene expression that may affect the biological function of peripheral nerves. Ten 1-week-old and ten 12-month-old healthy male Sprague-Dawley rats were divided into young（1 week old） and adult（12 months old） groups according to their ages. mRNA expression in the sciatic nerve was compared between young and adult rats using next-generation sequencing（NGS） and bioinformatics（n = 4/group）. The 18 groups of differentially expressed mRNA（DEmRNAs） were also tested by quantitative reverse transcription polymerase chain reaction（n = 6/group）. Results revealed that（1） compared with young rats, adult rats had 3608 groups of DEmRNAs. Of these, 2684 were groups of upregulated genes, and 924 were groups of downregulated genes. Their functions mainly involved cell viability, proliferation, differentiation, regeneration, and myelination.（2） The gene with the most obvious increase of all DEmRNAs in adult rats was Thrsp（log2 FC = 9.01, P 〈 0.05）, and the gene with the most obvious reduction was Col2 a1（log2 FC = -8.89, P 〈 0.05）.（3） Gene Ontology analysis showed that DEmRNAs were mainly concentrated in oligosaccharide binding, nucleotide-binding oligomerization domain containing one signaling pathway, and peptide-transporting ATPase activity.（4） Analysis using the Kyoto Encyclopedia of Genes and Genomes showed that, with increased age, DEmRNAs were mainly enriched in steroid biosynthesis, Staphylococcus aureus infection, and graft-versus-host disease.（5） Spearman＇s correlation coefficient method for evaluating NGS accuracy showed that the NGS results and quantitative reverse transcription polymerase chain reaction results were positively correlated（rs = 0.74, P 〈 0.05）. These findings confirm a difference in sciatic nerve gene expression between adult and young rats, suggesting that, in peripheral nerves, cells and the microenvironment change with age, thus influencing the function and repair of peripheral nerves.

Effect of Acetaldehyde on Oxidoreductases in Tissues of Rats at Different Ages

The toxicity of acetaldehyde and age related changes on oxidoreductases in the liver,brain, kidney, and musele of female albino rats (Wistar strain) were studied. The specific activities of lactate [LDH], isocitrate [ICDH (NAD/NADP)], succinate [SDH], malate [MDH], glutamate [GDH] and glucose-6-Phosphate [G-6-PDH] dehydrogenases were signifieantly inereased as a function of age. However, acetaldehyde treatment significantly inhibited oxidoreductases in the tissues of 21, 90 and 180 day old rats. Liver enzymes of young (21 days) rats exhibited greater sensitivity to acetaldehyde toxicity. Similar inhibition of oxidoreductases in brain and kidney of adult (180 days) rats treated with acetaldehyde was observed. LDH and GDH as compared to other enzymes studied showed higher susceptibility to acetaldehyde toxicity. The differential sensitivity of tissues and inhibition of oxidoreductases by acetaldehyde as a function of age could be attributed to hypoxic conditions, energy crisis, and mitochondrial structural changes. The results suggest that acetaldehyde affects oxidation of glucose via HMP shuni pathway, glycolytic pathway and Krebs cycle resulting in the impairment of carbohydrate metabolism

Association between delayed cardioprotection of aged rat myocytes and activation of mitogenactivated protein kinase

Objective To study the cardioprotective effects of hypoxic preconditioning (HPC) on aged rat ventricular myocytes and the cellular mechanism of protection Methods In the model of hypoxia/reoxygenation (H/R) of isolated ventricular myocytes of aged rat, the effects of HPC on aged rat ventricular myocytes against lethal H/R stimulated ischemia/reperfusion (I/R) injury 24 hours later and the changes of mitogen activated protein kinase (MAPK) system were observed in the present study Results HPC attenuated the lactate dehydrogenase (LDH) release and ATP depletion in myocytes and increased the viability of myocytes It was also found that MAPK and its down stream kinase—S6 kinase were also activated after HPC Conclusion There is delayed cardioprotection in cardiac myocytes of aged rat and the cellular mechanism underlying might involve the activation of MAPK system