Young Control Rats Research Articles

Vit D3 versus L Carnitine Supplement in Alleviating Age-Related Insulin Resistance in A Naturally Aging Rat Model

AbstractBackground: Insulin Resistance (IR) has long been rec-ognized as a characteristic of aging. Many studies recorded beneficial roles of Vitamin D3 (VD3) and L-Carnitine (LC) in obesity and type 2 diabetes.Aim of Study: To evaluate the role of VD3 versus LC in attenuating the age-related IR in a naturally aging rat model, clarifying their possible underlying mechanisms.Material and methods: Rats were divided into 4 groups; Young Control (YC), aged group, VD3-treated aged group (VD3-aged) and LC-treated aged group (LC-aged). Experi-mental procedures included measurement of body weight, Body Mass Index (BMI) and Oral Glucose Tolerance Tests (OGTT). The Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) index was also calculated. Assays of fasting serum glucose and insulin levels as well as serum tumor necrosis factor-a (TNF-a), interleukin-6 (IL-6) and adiponectin levels were performed. Moreover, skeletal muscle Sirtuin-1 (SIRT-1), Triglycerides (TGs) and TNF-a levels alongside with the glucose transporter-4 (GLUt4) mRNA expression were assessed.Results: Compared to YC rats, aged rats exhibited signif-icant increase in fasting serum insulin and HOMA-IR as well as an abnormal OGTT. Serum TNF-a and IL-6 levels were significantly increased, whereas serum adiponectin level was significantly decreased in old rats. Furthermore, the SIRT1 levels and GLUT 4 mRNA expression were significantly lower, whereas the TGs and TNF-a were significantly higher in skeletal muscle of aged rats compared to YC ones. On the other hand, these parameters, were equally and significantly attenuated in VD3 and LC supplemented rats compared to non-treated age matched group, except for the skeletal muscle SIRT-1 level which could be elevated only by VD3, while the anti-inflammatory and TGs lowering effects of LC were more prominent than VD3. Nevertheless, the overall effect of VD3 and LC on IR-related parameters were nearly equal.Conclusion: Both VD3 or LC administrations were equally effective in alleviating the age-related IR, thus may provide a possible therapeutic intervention in the aging population.

Increased BBB permeability contributes to EGCG-caused cognitive function improvement in natural aging rats: pharmacokinetic and distribution analyses.

Previous studies report that (-)-epigallocatechin-3-gallate (EGCG), the most abundant polyphenolic ingredient in green tea, has high efficacy against Alzheimer's disease (AD) in various in vivo and in vitro models. However, as a water-soluble component, how EGCG exerts its anti-AD effects in the brain was not elucidated. In the present study, we investigated the anti-AD mechanisms of EGCG in natural aging rats with cognitive impairments (CIs) assessed using Morris water maze. The rats were treated with EGCG (100 mg/kg per day, intragastrically) for 4 weeks. The expression of β-amyloid (Aβ1-42) in the brain was detected with immunohistochemical staining. We showed that EGCG administration significantly ameliorated the CI in the aging rats with CI and decreased Aβ1-42 plaque formation in their brains. Then we used an efficient ultra-performance liquid chromatography-tandem mass spectrometer method to evaluate EGCG concentrations in rat plasma and tissue distribution. We found that EGCG absorption was significantly increased in the aging with CI group compared with control young rats. After oral administration of EGCG (100 mg), EGCG could not be detected in the brain tissues of control young rats, but it was found in the brain tissue of aging rats with CI. By using Evans Blue assay, transmission electron microscopy, and Western blotting assay, we demonstrated that the permeability of blood-brain barrier (BBB) was significantly increased in aging rats with CI. These results suggest that the permeability change of BBB is the physiological structural basis for EGCG treatment to improve learning and memory, thus providing a solid evidence for EGCG druggability in anti-AD therapeutic field.

Effects of docosahexaenoic acid on locomotor activity in ethanol-treated HIV-1 transgenic rats.

Binge drinking affects the onset and progression of human immunodeficiency virus (HIV)-associated neurological disorders. The HIV-1 transgenic (HIV-1Tg) rat was created with a gag- and pol-deleted HIV-1 viral genome to mimic HIV-infected patients receiving combination anti-retroviral therapy (cART). Docosahexaenoic acid (DHA) is a marine compound that modulates inflammatory responses. Using HIV-1Tg rats subjected to binge exposure to ethanol (EtOH), this study examined whether DHA could reduce the detrimental neurological effects of EtOH and HIV proteins. Young adult male HIV-1Tg and F344 control rats received 4mL/kg/day saline as a control (Saline group), 20mg/kg/day DHA (DHA group), 4.8g/kg/day 52% w/v EtOH (EtOH group), or 4.8g/kg/day 52% w/v EtOH and 20mg/kg/d DHA (DHA+EtOH group) by gavage for 5weeks (n=6 per group). EtOH was administrated on days 5, 6, and 7 of each week. Locomotor activity (LMA) was assessed using open field tests before and 45, 90, 135, and 180min after each treatment. Repeated binge EtOH exposure gradually decreased LMA measured before daily treatments in HIV-1Tg and F344 rats, an effect that was reversed by DHA only in the HIV-1Tg rats. Decreased LMA of rats after treatment and under the influence of EtOH was less pronounced, and the reversal effect of DHA did not reach statistical significance. The plasma endotoxin level was significantly higher in HIV-1Tg rats than in F344 rats. IL-6 and IL-18 expression in the striatum was significantly higher in the HIV-1Tg EtOH group than in the F344 EtOH group. DHA significantly decreased the high levels of IL-6, IL-18, and NF-κB expression observed in the HIV-1Tg EtOH group. DHA appears to ameliorate inflammation and consequently lessen the reductions in LMA produced by the combination of EtOH and HIV-1 viral proteins.

Role of melatonin in glucose uptake by cardiomyocytes from insulin-resistant Wistar rats.

SummaryAimMelatonin supplementation reduces insulin resistance and protects the heart in obese rats. However, its role in myocardial glucose uptake remains unknown. This study investigated the effect of short-term melatonin treatment on glucose uptake by cardiomyocytes isolated from obese and insulin-resistant rats.MethodsCardiomyocytes were isolated from obese rats fed a high-calorie diet for 16 to 23 weeks, their age-matched controls, as well as young control rats aged four to eight weeks. After incubation with melatonin with or without insulin, glucose uptake was initiated by the addition of 2-deoxy-D-[3H] glucose and measured after 30 minutes. Additional control and obese rats received melatonin in the drinking water (4 mg/kg/day) for the last six weeks of feeding (20 weeks) and glucose uptake was determined in isolated cardiomyocytes after incubation with insulin. Intraperitoneal glucose tolerance and biometric parameters were also measured.ResultsObese rats (fed for more than 20 weeks) developed glucose intolerance. Cardiomyocytes isolated from these obese rats had a reduced response to insulin-stimulated glucose uptake (ISGU) (p < 0.05). Melatonin administration in vitro had no effect on glucose uptake per se. However, it increased ISGU by cardiomyocytes from the young rats (p < 0.05), while having no effect on ISGU by cardiomyocytes from the older control and obese groups. Melatonin in vivo had no significant effect on glucose tolerance, but it increased basal (p < 0.05) and ISGU by cardiomyocytes from the obese rats (50.1 ± 1.7 vs 32.1 ± 5.1 pmol/mg protein/30 min, p < 0.01).ConclusionThese data suggest that short-term melatonin treatment in vivo but not in vitro improved glucose uptake and insulin responsiveness of cardiomyocytes in obesity and insulin-resistance states.

Morphological alterations in the jejunal mucosa of aged rats and the possible protective role of green tea.

Gastrointestinal disorders become more prevalent with ageing. This study is aimed to describe morphological changes that occur in the jejunal mucosa of male albino rats as a result of ageing and the protec-tive effect of green tea (GT) extract. The experiment was performed on sixty rats: thirty young-adult (6-month old, body mass 200-220 g) and thirty old (24-month-old, body mass 220-260 g) animals. Each group was further divided into two subgroups (n = 15 each): control rats and GT-treated rats that received 1.5 mL (300 mg/kg/day) of GT extract for 14 weeks by oral gavage. Sections of the jejunum were stained with hematoxylin and eosin, periodic acid Schiff, toluidine blue and Mallory trichrome methods. The presence of proliferating cell nuclear antigen (PCNA)- and CD68-positive cells was evaluated by immunohistochemical staining. Ultrathin sections were prepared and examined by a transmission electron microscope (TEM). Jejunal sections of the old control rats showed distortion of submucosa and attenuated muscularis externa with decreased height of intestinal villi. The villi also showed partial loss of acidophilic brush border with wide spaces between enterocytes. Swollen, short, blunt or broad villi with abundant mononuclear cell infiltration of lamina propria and congested blood vessels were evident both by light and electron microscopy. The number of PCNA- and CD68-positive cells in jejunal mucosa of old rats was higher than in young rats. The activity of glutathione peroxidase (GPX) and total antioxidant capacity (TAC) in the mucosa of old control rats were lower, whereas malondialdehyde (MDA) levels were higher in the jejunal homogenates of old rats as compared to young control rats. Administration of GT extract protected the jejunal mucosa from age-related changes by restoring its histological structure. The treatment of old rats with GT extract significantly decreased MDA levels in the jejunum and increased TAC and GPX activity. The age-related changes of the morphology of rat jejunum could be ameliorated by prolonged supplementation of the green tea extract.

Upregulation of orexin/hypocretin expression in aged rats: Effects on feeding latency and neurotransmission in the insular cortex

Aging is associated with changes in numerous homeostatic functions, such as food intake, that are thought to be mediated by the hypothalamus. Orexin/hypocretin neurons of the hypothalamus regulate several physiological functions, including feeding, sleep and wakefulness. Evidence from both clinical and animal studies supports the notion that aging is associated with loss or dysregulation of the orexin system. Here, we used virus-mediated gene transfer to manipulate expression of orexin peptides in young and aged rats and examined behavioral and neurochemical correlates of food intake in these animals. Aged rats showed slower feeding latencies when presented with palatable food compared to young control rats, and these deficits were ameliorated by upregulation of orexin expression. Similarly, young animals treated with a virus designed to decrease preproorexin expression showed longer feeding latencies reminiscent of aged control rats. Feeding was also associated with increased acetylcholine, glutamate and GABA efflux in insular cortex of young control animals. Orexin upregulation did not restore deficits in feeding-elicited release of these neurotransmitters in aged rats, but did enhance basal neurotransmitter levels which may have contributed to the behavioral correlates of these genetic manipulations. These studies demonstrate that age-related deficits in behavioral and neurochemical measures of feeding are likely to be mediated, in part, by the orexin system. Because these same neurotransmitter systems have been shown to underlie orexin effects on cognition, treatments which increase orexin function may have potential for improving both physiological and cognitive manifestations of certain age-related disorders.

Myocardial susceptibility to ischaemia/reperfusion in obesity: a re-evaluation of the effects of age

BackgroundReports on the effect of age and obesity on myocardial ischaemia/reperfusion (I/R) injury and ischaemic preconditioning are contradictory. The aim of this study was to re-evaluate the effects of age and diet-induced obesity (DIO) on myocardial I/R injury and preconditioning potential.MethodsFour groups of Wistar male rats were used: age-matched controls (AMC) receiving standard rat chow for (i) 16 weeks and (ii) 16 months respectively; DIO rats receiving a sucrose-supplemented diet for (iii) 16 weeks and (iv) 16 months respectively. The ages of groups (i) and (iii) were 22 weeks (“young”) and groups (ii) and (iv) 17 months (“middle-aged”) at time of experimentation. Isolated perfused working hearts were subjected to 35 min regional ischaemia/1 h reperfusion. Endpoints were infarct size (tetrazolium staining) and functional recovery. Hearts were preconditioned by 3 × 5 min ischaemia/5 min reperfusion. Results were processed using GraphPad Prism statistical software.ResultsAge did not affect baseline heart function before induction of ischaemia and I/R damage as indicated by infarct size and similar values were obtained in hearts from both age groups. Age also had no effect on functional recovery of hearts during reperfusion after regional ischaemia in AMC rats, but cardiac output during reperfusion was better in hearts from middle-aged than young DIO rats.The diet reduced infarct size in hearts from young rats (% of area at risk: AMC: 32.4 ± 3.6; DIO: 20.7 ± 2.9, p < 0.05), with no differences in hearts from middle-aged rats (AMC: 24.6 ± 4.6; DIO: 28.3 ± 13.5, p = NS). Compared to their respective AMC, diet-induced obesity had no significant effect on functional recovery of hearts from both age groups after exposure to regional ischaemia.When exposed to the more severe stress of global ischaemia, the functional recovery potential of middle-aged DIO rats appeared to be impeded compared to hearts of young DIO rats, while age had no effect on the functional recovery of AMC hearts.Preconditioning reduced infarct size in hearts from young control rats and both middle-aged groups, but not from young DIO rats. Age had a significant effect on functional recovery in preconditioning: it was improved in hearts from young control and DIO rats, but depressed in both middle-aged groups.ConclusionsThe data showed that middle-age and obesity had no effect on baseline myocardial function and did not increase susceptibility to I/R damage upon exposure to regional ischaemia. On the contrary, obesity reduced I/R damage in young rats. Preconditioned aging hearts showed a decreased infarct size, but a reduction in functional recovery.

Clasmatodendrosis and β-amyloidosis in aging hippocampus.

Alterations of the tightly interwoven neuron/astrocyte interactions are frequent traits of aging, but also favor neurodegenerative diseases, such as Alzheimer disease (AD). These alterations reflect impairments of the innate responses to inflammation-related processes, such as β-amyloid (Aβ) burdening. Multidisciplinary studies, spanning from the tissue to the molecular level, are needed to assess how neuron/astrocyte interactions are influenced by aging. Our study addressed this requirement by joining fluorescence-lifetime imaging microscopy/phasor multiphoton analysis with confocal microscopy, implemented with a novel method to separate spectrally overlapped immunofluorescence and Aβ autofluorescence. By comparing data from young control rats, chronically inflamed rats, and old rats, we identified age-specific alterations of neuron/astrocyte interactions in the hippocampus. We found a correlation between Aβ aggregation (+300 and +800% of aggregated Aβ peptide in chronically inflamed and oldvs.control rats, respectively) and fragmentation (clasmatodendrosis) of astrocyte projections (APJs) (+250 and +1300% of APJ fragments in chronically inflamed and oldvs.control rats, respectively). Clasmatodendrosis, in aged rats, associates with impairment of astrocyte-mediated Aβ clearance (-45% of Aβ deposits on APJs, and +33% of Aβ deposits on neurons in oldvs.chronically inflamed rats). Furthermore, APJ fragments colocalize with Aβ deposits and are involved in novel Aβ-mediated adhesions between neurons. These data define the effects of Aβ deposition on astrocyte/neuron interactions as a key topic in AD biology.-Mercatelli, R., Lana, D., Bucciantini, M., Giovannini, M. G., Cerbai, F., Quercioli, F., Zecchi-Orlandini, S., Delfino, G., Wenk, G. L., Nos, D. Clasmatodendrosis and β-amyloidosis in aging hippocampus.

Age-Related Changes in Sirtuin 7 Expression in Calorie-Restricted and Refed Rats

Background: Sirtuins (SIRT1-7) have been implicated to mediate the beneficial effects of calorie restriction for healthy aging. While the physiological functions of SIRT7 are still poorly understood, SIRT7 has recently been shown to affect ribosome biogenesis, mitochondrial gene expression, and hepatic lipid metabolism. Objective: To analyze the effects of age and short-term calorie restriction (SCR) and subsequent refeeding on SIRT7 expression in key metabolic tissues. Methods: Four- and 24-month-old male Wistar rats were subjected to 40% SCR for 30 days, followed by ad libitum feeding for 2 or 4 days. Liver, white adipose tissue (WAT), heart and skeletal muscle samples were analyzed by real-time PCR and Western blotting for SIRT7 mRNA and protein expression, respectively. Results: Aging had diverse effects on SIRT7 levels in lipogenic tissues: both the mRNA and protein levels increased in the retroperitoneal depot (rWAT), did not change in the epididymal depot (eWAT), and decreased in the subcutaneous depot (sWAT) and the liver of old as compared to young animals. In the heart, extensor digitorum longus muscle (EDL) and soleus muscle (SOL), Sirt7 gene but not protein expression was lower in old than in young control rats. SCR did not affect SIRT7 expression in WAT and the liver in both age groups. In the heart of young animals, SCR did not affect SIRT7 mRNA or protein level. In EDL, SIRT7 protein but not mRNA levels decreased after SCR and remained reduced upon refeeding. In SOL, both SIRT7 mRNA and protein expression were inhibited by refeeding. In old rats, cardiac Sirt7 expression increased after SCR and refeeding. In old rats' EDL and SOL muscles, SIRT7 protein expression was inhibited by refeeding. Conclusion: Age-related changes of SIRT7 gene expression in key organs of energy homeostasis are tissue dependent.

Carnosine reverses the aging-induced down regulation of brain regional serotonergic system

The purpose of the present investigation was to study the role of carnosine, an endogenous dipeptide biomolecule, on brain regional (cerebral cortex, hippocampus, hypothalamus and pons-medulla) serotonergic system during aging. Results showed an aging-induced brain region specific significant (a) increase in Trp (except cerebral cortex) and their 5-HIAA steady state level with an increase in their 5-HIAA accumulation and declination, (b) decrease in their both 5-HT steady state level and 5-HT accumulation (except cerebral cortex). A significant decrease in brain regional 5-HT/Trp ratio (except cerebral cortex) and increase in 5-HIAA/5-HT ratio were also observed during aging. Carnosine at lower dosages (0.5–1.0μg/Kg/day, i.t. for 21 consecutive days) didn't produce any significant response in any of the brain regions, but higher dosages (2.0–2.5μg/Kg/day, i.t. for 21 consecutive days) showed a significant response on those aging-induced brain regional serotonergic parameters. The treatment with carnosine (2.0μg/Kg/day, i.t. for 21 consecutive days), attenuated these brain regional aging-induced serotonergic parameters and restored towards their basal levels that observed in 4 months young control rats. These results suggest that carnosine attenuates and restores the aging-induced brain regional down regulation of serotonergic system towards that observed in young rats’ brain regions.

Pectinase-treated Panax ginseng ameliorates hydrogen peroxide-induced oxidative stress in GC-2 sperm cells and modulates testicular gene expression in aged rats

BackgroundTo investigate the effect of pectinase-treated Panax ginseng (GINST) in cellular and male subfertility animal models. MethodsHydrogen peroxide (H2O2)-induced mouse spermatocyte GC-2spd cells were used as an in vitro model. Cell viability was measured using MTT assay. For the in vivo study, GINST (200 mg/kg) mixed with a regular pellet diet was administered orally for 4 mo, and the changes in the mRNA and protein expression level of antioxidative and spermatogenic genes in young and aged control rats were compared using real-time reverse transcription polymerase chain reaction and western blotting. ResultsGINST treatment (50 μg/mL, 100 μg/mL, and 200 μg/mL) significantly (p < 0.05) inhibited the H2O2-induced (200 μM) cytotoxicity in GC-2spd cells. Furthermore, GINST (50 μg/mL and 100 μg/mL) significantly (p < 0.05) ameliorated the H2O2-induced decrease in the expression level of antioxidant enzymes (peroxiredoxin 3 and 4, glutathione S-transferase m5, and glutathione peroxidase 4), spermatogenesis-related protein such as inhibin-α, and specific sex hormone receptors (androgen receptor, luteinizing hormone receptor, and follicle-stimulating hormone receptor) in GC-2spd cells. Similarly, the altered expression level of the above mentioned genes and of spermatogenesis-related nectin-2 and cAMP response element-binding protein in aged rat testes was ameliorated with GINST (200 mg/kg) treatment. Taken together, GINST attenuated H2O2-induced oxidative stress in GC-2 cells and modulated the expression of antioxidant-related genes and of spermatogenic-related proteins and sex hormone receptors in aged rats. ConclusionGINST may be a potential natural agent for the protection against or treatment of oxidative stress-induced male subfertility and aging-induced male subfertility.

Acute induction of uncoupling protein 1 by citrulline in cultured explants of white adipose tissue from lean and high-fat-diet-fed rats

A diet enriched with citrulline (CIT) reduces white adipose tissue (WAT) mass. We recently showed that CIT stimulated β-oxidation in rat WAT explants from young (2–4 months) but not old (25 months) rats. Here we show that both in old rats and high-fat-diet-fed young rats, uncoupling protein one (UCP1) mRNA and protein expressions were weaker than those in young control rats. Selectively in WAT from young rats, a 24h CIT treatment up-regulated expressions of UCP1, peroxisome proliferator-activated receptor-α (PPARα), PPARγ-coactivator-1-α and mitochondrial-transcription-factor-A whereas it down-regulated PPARγ2 gene expression, whatever the diet. These results suggest that CIT induces a new metabolic status in WAT, with increased β-oxidation and uncoupling of respiratory chain, resulting in energy expenditure that favors fat mass reduction.

Camel Thorn Extract Reduces Activity of Angiotensin-Converting Enzyme in Rat Aorta Increased during Aging and Treatment with NO-Synthase Inhibitor

We studied the effect of camel thorn extract on activity of angiotensin-converting enzyme in rat aorta increased in animals during aging or treatment with NO-synthase inhibitor. Intake of camel thorn extract with drinking water reduced activity of angiotensin-converting enzyme; the effect increased with increasing the dose of the extract. Angiotensin-converting enzyme activity in older rats and animals treated with NO-synthase inhibitor decreased to the values observed in young control rats at extract concentration of 0.2%. Comparison of the effects of camel thorn extract with those of flavonoid taxifolin showed that the extract was not inferior to taxifolin in preventing the early stages of aortic atherosclerosis caused by increased activity of angiotensin-converting enzyme.

Age-related changes in rat prostate tissue; perspective of protein oxidation

Background: Increased systemic oxidative stress is considered as an important risk factor for prostate cancer occurrence; however, the relationship between impaired redox homeostasis of prostate tissue and aging remains unclear.Objective: In our study, we hypothesized that age-related deterioration of redox homeostasis in prostate tissue may be considered as a predisposing factor for prostate cancer occurrence.Methods: Sprague–Dawley rats were divided into two groups as young control (5 months) and naturally aged (24 months). We investigated the levels of oxidant and antioxidant parameters in prostate tissue.Results: Advanced oxidation protein products, protein carbonyl, non-protein thiol and lipid hydroperoxides levels of aged rats were significantly higher than in the young control rats (p < 0.01, p < 0.05, p < 0.001, p < 0.05, respectively). Additionally, antioxidant activity of Cu-Zn-superoxide dismutase in elderly group was significantly lower than young controls (p < 0.05).Conclusions: We suggest that increased non-protein thiol levels found in aged rats may prevent further dissemination of oxidative protein damage. We also propose that the increased levels of oxidative protein damage markers and decreased Cu-Zn superoxide dismutase activity in aged prostate may be considered as a predisposing factor for prostate cancer. Further studies are warranted to clarify all these oxidative changes as initiation factors for prostate cancer in the association of aging with prostate cancer.

Diffusion tensor and volumetric magnetic resonance measures as biomarkers of brain damage in a small animal model of HIV.

BackgroundThere are currently no widely accepted neuro-HIV small animal models. We wanted to validate the HIV-1 Transgenic rat (Tg) as an appropriate neuro-HIV model and then establish in vivo imaging biomarkers of neuropathology, within this model, using MR structural and diffusion tensor imaging (DTI).MethodsYoung and middle-aged Tg and control rats were imaged using MRI. A subset of middle-aged animals underwent longitudinal repeat imaging six months later. Total brain volume (TBV), ventricular volume (VV) and parenchymal volume (PV = TBV–VV) were measured. Fractional anisotropy (FA) and mean diffusivity (MD) values of the corpus callosum (CC) were calculated from DTI data.ResultsTBV and PV were smaller in Tg compared to control rats in young and middle-aged cohorts (p<0.0001). VV increased significantly (p = 0.005) over time in the longitudinal Tg cohort. There were lower FA (p<0.002) and higher MD (p<0.003) values in the CC of middle-aged Tg rats compared to age-matched controls. Longitudinally, MD significantly decreased over time in Tg rats (p<0.03) while it did not change significantly in the control cohort over the same period of time (p>0.05).ConclusionsWe detected brain volume loss in the Tg rat, probably due to astrocytic dysfunction/loss, loss of structural/axonal matrix and striatal neuronal loss as suggested by immunofluorescence. Increased MD and decreased FA in the CC probably reflect microstructural differences between the Tg and Control rats which could include increased extracellular space between white matter tracts, demyelination and axonal degeneration, among other pathologies. We believe that the Tg rat is an adequate model of neuropathology in HIV and that volumetric MR and DTI measures can be potentially used as biomarkers of disease progression.

Caloric restriction impedes age-related decline of mitochondrial function and neuronal activity.

Caloric restriction (CR) prolongs lifespan and retards many detrimental effects of aging, but its effect on brain mitochondrial function and neuronal activity--especially in healthy aging--remains unexplored. Here we measured rates of neuronal glucose oxidation and glutamate-glutamine neurotransmitter cycling in young control, old control (i.e., healthy aging), and old CR rats using in vivo nuclear magnetic resonance spectroscopy. We found that, compared with the young control, neuronal energy production and neurotransmission rates were significantly reduced in healthy aging, but were preserved in old CR rats. The results suggest that CR mitigated the age-related deceleration of brain physiology.

Pectinase-treated Panax ginseng extract (GINST) rescues testicular dysfunction in aged rats via redox-modulating proteins

The root of Panax ginseng improves testicular function both in humans and animals. However, the molecular mechanism by which ginseng exerts this effect has not been elucidated. Changes in protein expression in the rat testis in response to a pectinase-treated P. ginseng extract (GINST) were identified using 2-dimensional electrophoresis (2-DE) and MALDI-TOF/TOF MS. Number of sperm, Sertoli cells and germ cells, and the Sertoli Cell Index decrease in the testis of aged rats (AR) relative to young control rats (YCR). However, those parameters were completely restored in GINST-treated AR (GINST-AR). A proteomic analysis identified 14 proteins that were differentially expressed between vehicle-treated AR (V-AR) and GINST-AR. Out of these, the expression of glutathione-S-transferase (GST) mu5 and phospholipid hydroperoxide (PH) glutathione peroxidase (GPx) was significantly up-regulated in GINST-AR compared to V-AR. The activity of GPx and GST, as well as the expression of glutathione, in the testis of GINST-AR was higher than that in V-AR. The levels of lipid peroxidation (LPO) increased in AR compared with YCR, but this change was reversed by GINST-AR. These results suggest that the administration of GINST enhances testicular function by elevating GPx and GST activity, thus resulting in increased glutathione, which prevents LPO in the testis.

Long-term atorvastatin improves age-related endothelial dysfunction by ameliorating oxidative stress and normalizing eNOS/iNOS imbalance in rat aorta

Vascular aging is characterized by vascular cell senescence, increased oxidative stress, and endothelial and inducible nitric oxide (NO) synthase (eNOS/iNOS) imbalance, which reduces NO bioavailability and causes endothelial dysfunction. We investigated whether long-term administration of atorvastatin affects endothelial dysfunction and the underlying mechanisms. Aortas from young (2months), middle-aged (12months), and old (20months) control rats that had received a routine diet and from old rats (20months) that had received a diet mixed with atorvastatin (5mg/kg/day) for 8months were investigated. Senescent phenotype, vascular reactivity, superoxide dismutase (SOD), malonyldialdehyde (MDA), total NO, calcium-dependent and -independent NOS activity, and eNOS, iNOS, and sirtuin-1 (SIRT1) expression at the transcriptional and translational levels were assessed in rat aortas. Comparisons between young, middle, and old control rats showed that the senescent phenotype was enhanced in intima and media (p<0.01), and that MDA, calcium-independent NOS activity, and iNOS increased with age (p<0.01), whereas endothelium-dependent relaxation, SOD, NO, calcium-dependent NOS activity, eNOS, the eNOS/iNOS ratio, and SIRT1 declined with age (p<0.01). Compared with old controls, long-term administration of atorvastatin to old rats inhibited the senescent phenotype (p<0.05), improved endothelium-dependent relaxation (p<0.05 or 0.01), decreased MDA (p<0.01), increased SOD, NO, eNOS, and SIRT1 expression (p<0.01), and inhibited iNOS expression (not detectable) in aged rat aortas. The results indicate that the long-term administration of atorvastatin improves age-related endothelial dysfunction in aged rats via inhibition of the senescent phenotype, amelioration of oxidative stress, and normalization of eNOS/iNOS imbalance.

Supplementation of complex milk lipid concentrate (CMLc) improved the memory of aged rats

ObjectivesThe socio-economic impact from age-related mental decline is escalating. Supplementation of functional foods for sustaining mental health is desirable. We examined the effect of long-term supplementation of complex milk lipid concentrate (CMLc), mixed dairy phospholipids, on memory and associated vascular and neuronal changes in aged rats.MethodsFisher/Norway Brown rats were used. Two groups of aged rats (24 months) were fed with either gelatin-formulated CMLc or blank gelatin as the control, for 4 months. To determine age-related changes, a young group (5 months) was also fed with blank gelatin. Morris water maze tests were carried out after the supplementation and brain tissues were collected for biological analysis.ResultsThe aged control rats learnt to locate the platform slower than the young control rats during acquisition trials (*P < 0.05), and made fewer entries to and more initial heading errors from the platform zone during testing trials (*P < 0.05). The CMLc supplementation improved memory by showing the reduced initial heading errors in a delayed probe trial (#P < 0.05). We also found that the aged rats with CMLc supplementation improved vascular density, dopamine output, and neuroplasticity (#P < 0.05) in the brain regions involved in memory compared with that of the aged control rats.DiscussionThe data suggested that the supplementation of CMLc during the early stage of brain aging may prevent memory decline possibly through improving vascular and neuronal function.

Impact of chronic nicotine administration on bone mineral content in young and adult rats: A comparative study

The aim of this study was to evaluate the effects of chronic nicotine administration on bone mineral homeostasis in rapidly growing young rats in comparison to effects in adult male rats. Two doses of nicotine (3 and 4.5mg/kg/day, as nicotine hydrogen tartrate) were used and rat treatment was continued for 6 months. In this study, all nicotine-treated rats weighed less than control rats and the effect was dose-dependent. Also, rats treated with nicotine had lower femoral wet weight and showed a significant reduction in femoral mid-shaft cortical width and femoral and lumbar vertebral ash weights. These effects were associated with a significant reduction of ash calcium and phosphorus contents of the femora and lumbar vertebrae. The bone mineral-lowering effects of nicotine were more severe in the lumbar vertebral spongy bone than in the femoral compact bone and these changes were more marked in adult rats than in young rats. An additional interesting observation was that the femora of young rats treated with nicotine were significantly shorter than those of control young rats. Also, the values of the femoral ash weight per unit length were significantly decreased in nicotine-treated adult rats but not in nicotine-treated young rats. Thus, these results show that nicotine-induced changes in bone vary with age. The clinical relevance of this study is that it may provide justification to insist that all people in general and the risky young group in particular should be warned against the hazards of the negative effects of nicotine on bone.