Regular Cages Research Articles

The Effect of Temporal and Spatial Stimuli on the Refractive Status of Guinea Pigs Following Natural Emmetropization

To understand the visual information essential for maintaining stable refraction after emmetropization, we investigated the effects of spatial and temporal stimuli on the refractive status of guinea pigs. Eighty-eight guinea pigs (4 weeks old) were randomly divided into 10 groups. Thirty animals were raised in backgrounds of gray (N = 13), square-wave (N = 9), or sine-wave grating (N = 8). Thirty-one animals were raised in gray backgrounds with three frequencies of flicker: gray-1-Hz (n = 10), gray-6-Hz (n = 12), and gray-20-Hz (n = 9). Eighteen animals were raised in regular cages with different frequencies of flicker (n = 6 respectively in 1-Hz-, 6-Hz-, and 20-Hz-flicker groups). Nine animals were raised in regular cages with no additional stimuli and used as normal controls. Ocular biometry was measured before and after 3 weeks of exposure to the test environments. Guinea pigs raised in the gray background for 3 weeks developed myopia, -6.1 ± 2.1 diopters (D), whereas those exposed to either sine-wave or square-wave gratings, or raised in regular cages, retained stable refractions. Animals in the gray-6-Hz group developed lower myopia, -2.7 ± 2.7 D, than the gray group not exposed to flicker. Animals stimulated with a range of flickering frequencies in regular cages also developed myopia but to a lower degree, -3.1 to 0.2 D, than those in gray backgrounds, -5.0 to -2.7 D. Guinea pigs require both spatial and temporal stimuli to maintain stable refractions. The influence of temporal stimuli on refraction varies with the type and amount of spatial information available in the visual environment.

Voluntary Exercise Prevents Lead‐Induced Elevation of Oxidative Stress and Inflammation Markers in Male Rat Blood

Regular mild exercise enhances antioxidant and anti-inflammatory systems of the body. The present study investigates voluntary exercise effects on lead toxicity as a known oxidative stressor. Male Sprague-Dawley rats were randomly divided into 2 groups. Sedentary control: the animals were housed 7 weeks in the regular cages. Exercise group: the animals were housed 7 weeks in the running wheel equipped cages, that is, the animal model of voluntary exercise. During the 7th week, all animals were administered lead acetate. Blood samples were collected at the end of the 6th week and 7th week (before and after lead administrations). Glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA), and tumor necrosis factor (TNF-α) were measured in the samples. Our results showed that lead administration reduced blood SOD, GPx and CAT and increased TNF-α; in the controls, but in the exercise group, changes were not statistically significant. MDA in both groups increased after lead injections but it was significantly lower in exercise group compared to the sedentary animals. We concluded that voluntary exercise may be considered as a preventive tool against lead-induced oxidative stress and inflammation.

Adverse cardiac remodelling in spontaneously hypertensive rats: acceleration by high aerobic exercise intensity

In the present study it was hypothesized that voluntary aerobic exercise favours a pro-fibrotic phenotype and promotes adverse remodelling in hearts from spontaneously hypertensive rats (SHRs) in an angiotensin II-dependent manner. To test this, female SHRs at the age of 1 year were started to perform free running wheel exercise. Captopril was used to inhibit the renin-angiotensin system (RAS). Normotensive rats and SHRs kept in regular cages were used as sedentary controls. Training intensity, expressed as mean running velocity, was positively correlated with the left ventricular mRNA expression of TGF-β(1), collagen-III and biglycan but negatively correlated with the ratio of sarcoplasmic reticulum Ca(2+)-ATPase (SERCA)2a to Na(+)-Ca(2+) exchanger (NCX). A pro-fibrotic phenotype was verified by Picrosirius red staining. Sixty-seven per cent of SHRs performing free running wheel exercise died either spontaneously or had to be killed during a 6 month follow-up. In the presence of captopril, aerobic exercise did not show a similar positive correlation between training intensity and the expression of fibrotic markers. Moreover, in SHRs receiving captopril and performing free running wheel exercise, a training intensity-dependent reverse remodelling of the SERCA2a-to-NCX ratio was observed. None of these rats died spontaneously or had to be killed. In captopril-treated SHRs performing exercise, expression of mRNA for decorin, a natural inhibitor of TGF-β(1), was up-regulated. Despite these differences between SHR-training groups with and without captopril, positive training effects (lower resting heart rate and no progression of hypertension) were found in both groups. In conclusion, high aerobic exercise induces an angiotensin II-dependent adverse remodelling in chronic pressure overloaded hearts. However, high physical activity can potentially induce reverse remodelling in the presence of RAS inhibition.

Cholesterol esterification by ACAT2 is essential for efficient intestinal cholesterol absorption: evidence from thoracic lymph duct cannulation

The hypothesis tested in this study was that cholesterol esterification by ACAT2 would increase cholesterol absorption efficiency by providing cholesteryl ester (CE) for incorporation into chylomicrons. The assumption was that absorption would be proportional to Acat2 gene dosage. Male ACAT2⁺/⁺, ACAT2⁺/⁻, and ACAT2⁻/⁻ mice were fed a diet containing 20% of energy as palm oil with 0.2% (w/w) cholesterol. Cholesterol absorption efficiency was measured by fecal dual-isotope and thoracic lymph duct cannulation (TLDC) methods using [³H]sitosterol and [¹⁴C]cholesterol tracers. Excellent agreement among individual mice was found for cholesterol absorption measured by both techniques. Cholesterol absorption efficiency in ACAT2⁻/⁻ mice was 16% compared with 46-47% in ACAT2⁺/⁺ and ACAT2⁺/⁻ mice. Chylomicrons from ACAT2⁺/⁺ and ACAT2⁺/⁻ mice carried ∼80% of total sterol mass as CE, whereas ACAT2⁻/⁻ chylomicrons carried >90% of sterol mass in the unesterified form. The total percentage of chylomicron mass as CE was reduced from 12% in the presence of ACAT2 to ∼1% in ACAT2⁻/⁻ mice. Altogether, the data demonstrate that ACAT2 increases cholesterol absorption efficiency by providing CE for chylomicron transport, but one copy of the Acat2 gene, providing ∼50% of ACAT2 mRNA and enzyme activity, was as effective as two copies in promoting cholesterol absorption.

Prolonged Upright Posture Induces Calcified Hypertrophy in the Cartilage End Plate in Rat Lumbar Spine

Both forelimbs of rats were amputated and these rats were kept in the custom-made cages to keep prolonged and repeated upright posture. Changes of bone were observed in the lumbar vertebrae at three different time points after the surgery. To investigate the effect of prolonged and repeated upright posture on the cartilage end plate of rat lumbar vertebrae. Previous studies show calcified hypertrophy is related to mechanical stress, but there are no clear evidences to indicate whether or not long-term and repeated assumption of the upright posture could result in calcified hypertrophy in cartilage end plate of rat lumbar spine. The forelimbs of 30 rats were amputated when they were 1 month old. These rats were kept in the custom-made cages and were forced to stand upright on their hind-limbs and tails to obtain water and food. Normal rats of the same ages kept in regular cages were used as control. The rats were killed at 5, 7, and 9 months after the surgery and lumbar vertebrae samples were harvested for micro-CT, histologic, and immunohistochemical studies. Total RNA isolated from these samples were used for real-time RT-PCR of type X collagen (Col10α1), vascular endothelial growth factor (VEGF), and transforming growth factor β1 (TGF-β1). Micro-CT showed increased inner part of cartilage end plate. Histologic revealed peripheral hypertrophy of disc after the surgery. Immunostaining and real-time RT-PCR showed increased protein and mRNA expression of type X collagen, VEGF, and TGF-β1. Prolonged upright posture induces cartilage end plate calcification and hypertrophy in rat lumbar spine.

Prolonged and Repeated Upright Posture Promotes Bone Formation in Rat Lumbar Vertebrae

Both forelimbs of rats were amputated and these rats were kept in the custom-made cages to keep prolonged and repeated upright posture. Changes of bone were observed in the lumbar vertebrae at three different time points after the surgery. OBJECTIVE.: To investigate the effect of prolonged and repeated upright posture on bone formation of rat lumbar vertebrae. Previous studies show long-term and repeated load-induced bone formation, but there are no clear evidences to indicate whether or not long-term and repeated assumption of the upright posture could result in bone formation at rat lumbar vertebrae. The forelimbs of 30 rats were amputated when they were 1 month old. These rats were kept in the custom-made cages and were forced to stand upright on their hindlimbs and tails to obtain water and food. Normal rats of the same ages kept in regular cages were used as control. The rats were sacrificed at 5, 7, and 9 months after the surgery and lumbar vertebrae samples were harvested for micro-computed tomographic (CT), histological, and immunohistochemical studies. Total RNA isolated from these samples were used for real-time polymerase chain reaction of type I collagen (Col1α2), type X collagen (Col10α1), transforming growth factor-β1 (TGF-β1) and its related nuclear transcript factor runt-related transcription factor 2 (Runx2), as well as the biomarker of angiogenesis and vascular invasion, which is also a prerequisite for endochondral bone formation: vascular endothelial growth factor (VEGF). Micro-CT and histological studies showed increased trabecular bone density and increased osteoblast quantities of lumbar vertebrae after surgery. Immunostaining revealed increased protein expression of type I collagen, type X collagen, TGF-β, and VEGF. Real-time polymerase chain reaction showed upregulated expression of Col1α2, Col10α1, VEGF, TGF-β1, and Runx2 mRNA. Upright posture induces bone acquisition in the rats' lumbar spine, primarily through the mode of the endochondral ossification, which is associated with increased loading, activated VEGF, and TGF-β1 signaling.

Prolonged Upright Posture Induces Degenerative Changes in Intervertebral Discs of Rat Cervical Spine

An in vivo study of the cervical intervertebral discs (IVDs) response to upright posture was performed using an amputated bipedal rat model. To investigate the effects of upright posture on IVDs of rat cervical spine. The distinct arrangement of human neck muscle from that of cat and rhesus indicated that in the evolution process, upright posture might have affected cervical spine of human ancestors. However, the effects of upright posture on cervical spine have not been assessed. Forty-one-month-old rats were randomly divided into 5-month-control, 5-month-surgery, 7-month-control, and 7-month surgery group (n = 10 per group). Both forelimbs of 2 surgery group rats were amputated, and those rats were then induced to be upright in the custom-made cages. Two control group rats were kept in regular cages. These rats were respectively killed at the fifth and seventh month after surgery and the IVD samples of lumbar spine were harvested for histologic and immunohistochemical studies. Total RNA isolated from these samples were used for real-time polymerase chain reaction of type II collagen (Col2a1), type X collagen, matrix metalloproteinase 13 (MMP-13), MMP-3, aggre-can, and aggrecanase-2 (ADAMTS-5). Upright posture affects histologic changes of the cervical IVDs such as fissures of anulus fibrosus and decreased height of disc, decreased protein level of Col2a1 at nucleus pulposus and anulus fibrosus, up-regulated MMP-13, MMP-3, ADAMTS-5, and type X collagen mRNA expression, and downregulated mRNA expression of Col2a1 and aggrecan. Upright stance accelerates cervical disc degeneration in rats.

Leg Amputation Accelerates Senescence of Rat Lumbar Intervertebral Discs

Several senescence biomarkers were observed to investigate cell senescence in degenerative intervertebral lumbar discs of foreleg-amputated rats. To determine if cell senescence is accelerated in degenerative intervertebral lumbar disc cells in an upright-rat model. Cellular senescence was accelerated in human and sand rat degenerative intervertebral disc (IVD) cells. Repeated use of upright posture by rats contributed to degenerative disc changes. No convincing evidence of cell senescence was observed in the lumbar disc of the foreleg amputated rat. The forelimbs of 20 rats were amputated at 1 month of age such that they maintained an upright stance; rats were housed in custom-made cages. Nonamputated rats, also 1 month of age, were kept in regular cages and served as a control group. The lumbar IVDs were harvested from rats in 2 groups, at 5 or 9 months following amputation. Senescence-associated-β-galactosidase-positive staining was used to detect cell senescence. p16INK4a and p27KIP were assessed by immunohistochemistry analysis. Total RNA isolated from these samples was used to measure the gene expression of p16INK4a, RB, cyclin D1, CDK4, PTEN, p27KIP, p19ARF, p21, TERT, and RAGE by real-time polymerase chain reaction assay. The highest levels of SA-β-GAL activity were detected in 9-month amputated rats. Quantitative immunohistochemical analysis showed that there were highest rates of p16INK4a and p27KIP protein expression in the cartilage endplate and anulus fibrosus of 9-month amputated rats. The mRNA levels of p16INK4a, RB, PTEN, p27KIP, p19ARF, and RAGE were upregulated. The increased cyclin D1 mRNA level was statistically significant only at the ninth month following amputation; CDK4 and TERT mRNA levels were downregulated to a similar extent at both points compared with nonamputated controls. mRNA expression of p21 was significantly downregulated. Accelerated cell senescence was associated with forelimb amputation that causes abnormal loading in rat lumbar IVDs.

Conditioned response suppression in the IntelliCage: assessment of mouse strain differences and effects of hippocampal and striatal lesions on acquisition and retention of memory

The IntelliCage allows fully automated continuous testing of various behaviours in the home cage environment without handling the mice. Here we tested whether conditioned avoidance is retained after a time period delay spent outside the IntelliCage. During the training, nosepokes in one of the four learning corners were punished with an air-puff. After 24h of training, the mice were placed in regular cages for 24h. During the last 18h of this interval, the mice were water deprived and then returned to the IntelliCage for a probe trial where drinking was allowed in all corners. The C57BL/6 mice developed a significant suppression of nosepoking in the punished corner during training, and the avoidance was carried over to the following probe trial. Repetition of the experiment by delivering punishment in a different corner assigned to individual mice revealed a similar performance pattern. Comparison between the different strains revealed a reduced nosepoke suppression in DBA/2 and B6D2F1 mice as compared to C57BL/6 mice in the probe trial, despite similar error rates during the training with short (1-s) air-puffs. However, the performance of the three strains in the probe trial were equalised when the air-puffs were prolonged until the end of the corner visit. Significant extinction of the nosepoke suppression occurred after 6 days. A prolonged interval (7 days) between the training and the probe trial resulted in a loss of suppression in DBA/2 mice, but not in C57BL/6 and B6D2F1 mice. Additional experiments revealed that performance in the probe trial was dependent on a complex set of intramaze cues. Testing of mice with bilateral excitotoxic lesions of the hippocampus or dorso-lateral striatum revealed that learning this task was dependent on an intact hippocampus, but not on an intact striatum. In summary, the conditioned nosepoke suppression test presented here is sensitive to both genetic differences and hippocampal lesions. This test could be applied to the screening of mutant mice with impaired hippocampal functions more efficiently than those of the standard memory tests.

Early postnatal enriched environment decreases retinal degeneration induced by monosodium glutamate treatment in rats

Environmental enrichment is known to influence the development of the nervous system and it provides beneficial effects in various kinds of brain lesions. Enriched housing conditions also influence the development and functioning of the visual system. The aim of the present study was to investigate whether retinal degeneration induced by neonatal monosodium glutamate (MSG) in rats can be ameliorated by expanded cage size or enriched environment. Control rats were kept in a regular cage, another group of pups was kept in an expanded cage and a third group was kept under complex environmental enriched conditions from the first postnatal day. Half of the rats received MSG treatment on postnatal days 1, 5, and 9, while the other half of the groups received only saline treatment. Retinas were removed at 5 weeks of age and processed for histological analysis. Microscopical analysis revealed a substantial inner retinal degeneration in MSG-treated animals: the retinal thickness was less than 25% of the normal retinas, and the inner layers were completely fused. Expanded cage environment had a significant protective effect: the layers of the retina were well visible, and the thickness of the entire retina had a nearly 50% amelioration. Best results were obtained in retinas from rats living in enriched environment: the retina suffered only an approximately 25% reduction in thickness, and all layers were significantly thicker than in MSG-treated retinas. In summary, the present study showed that expanded field provided some degree of neuroprotection, while a complex environmental enrichment led to a manifest protection against retinal degeneration induced by neonatal MSG treatment in rats.

Early postnatal enriched environment decreases retinal degeneration induced by monosodium glutamate treatment in rats

Event Abstract Back to Event Early postnatal enriched environment decreases retinal degeneration induced by monosodium glutamate treatment in rats Gabor Horvath1*, Krisztina Szabadfi2, Tamas Atlasz2, Peter Kiss1, Levente Hamza2, József Farkas1, Andrea Tamas1, Andrea Lubics1, Robert Gabriel2 and Dóra Reglődi1 1 Department of Anatomy, University of Pecs, Hungary 2 Department of Experimental Zoology and Neurobiology, University of Pecs, Hungary Environmental enrichment influences the development of the nervous system and provides beneficial effects in various kinds of brain lesions. Enriched housing conditions also influence the development and functioning of the visual system. The aim of the present study was to investigate whether retinal degeneration induced by neonatal monosodium-glutamate (MSG) in rats can be ameliorated by expanded cage size or enriched environment. Control rats were kept in a regular cage, another group was kept in an expanded cage and a third group was kept under complex environmental enriched conditions from the first postnatal day. Half of the rats received MSG treatment on postnatal days 1, 5, and 9, while the other half of the groups received only saline. Retinas were removed 5 weeks later and processed for histological analysis. Microscopical analysis revealed a substantial inner retinal degeneration in MSG-treated animals: the retinal thickness was less than 25% of the normal retinas, and the inner layers were completely fused. Expanded cage had a significant protective effect: the layers of the retina were well visible, and the thickness of the entire retina had a nearly 50% amelioration. Best results were obtained in retinas from rats living in enriched environment: the retina suffered only an approximately 25% reduction in thickness, and all layers were significantly thicker than in MSG-treated retinas. In summary, the present study showed that expanded field provided some degree of neuroprotection, while a complex environmental enrichment led to a manifest protection against retinal degeneration induced by neonatal MSG treatment. Support:OTKA:K72592;F67830;78480;T061766;Richter Conference: 12th Meeting of the Hungarian Neuroscience Society, Budapest, Hungary, 22 Jan - 24 Jan, 2009. Presentation Type: Poster Presentation Topic: Pathophysiology and neurology - degenerative disorders Citation: Horvath G, Szabadfi K, Atlasz T, Kiss P, Hamza L, Farkas J, Tamas A, Lubics A, Gabriel R and Reglődi D (2009). Early postnatal enriched environment decreases retinal degeneration induced by monosodium glutamate treatment in rats. Front. Syst. Neurosci. Conference Abstract: 12th Meeting of the Hungarian Neuroscience Society. doi: 10.3389/conf.neuro.01.2009.04.154 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 05 Mar 2009; Published Online: 05 Mar 2009. * Correspondence: Gabor Horvath, Department of Anatomy, University of Pecs, Pecs, Hungary, figgol@freemail.hu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Gabor Horvath Krisztina Szabadfi Tamas Atlasz Peter Kiss Levente Hamza József Farkas Andrea Tamas Andrea Lubics Robert Gabriel Dóra Reglődi Google Gabor Horvath Krisztina Szabadfi Tamas Atlasz Peter Kiss Levente Hamza József Farkas Andrea Tamas Andrea Lubics Robert Gabriel Dóra Reglődi Google Scholar Gabor Horvath Krisztina Szabadfi Tamas Atlasz Peter Kiss Levente Hamza József Farkas Andrea Tamas Andrea Lubics Robert Gabriel Dóra Reglődi PubMed Gabor Horvath Krisztina Szabadfi Tamas Atlasz Peter Kiss Levente Hamza József Farkas Andrea Tamas Andrea Lubics Robert Gabriel Dóra Reglődi Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Voluntary exercise inhibits intestinal tumorigenesis in Apc Min/+mice and azoxymethane/dextran sulfate sodium-treated mice

BackgroundEpidemiological studies suggest that physical activity reduces the risk of colon cancer in humans. Results from animal studies, however, are inconclusive. The present study investigated the effects of voluntary exercise on intestinal tumor formation in two different animal models, ApcMin/+ mice and azoxymethane (AOM)/dextran sulfate sodium (DSS)-treated mice.MethodsIn Experiments 1 and 2, five-week old female ApcMin/+ mice were either housed in regular cages or cages equipped with a running wheel for 6 weeks (for mice maintained on the AIN93G diet; Experiment 1) or 9 weeks (for mice on a high-fat diet; Experiment 2). In Experiment 3, male CF-1 mice at 6 weeks of age were given a dose of AOM (10 mg/kg body weight, i.p.) and, 12 days later, 1.5% DSS in drinking fluid for 1 week. The mice were then maintained on a high-fat diet and housed in regular cages or cages equipped with a running wheel for 16 weeks.ResultsIn the ApcMin/+ mice maintained on either the AIN93G or the high-fat diet, voluntary exercise decreased the number of small intestinal tumors. In the AOM/DSS-treated mice maintained on a high-fat diet, voluntary exercise also decreased the number of colon tumors. In ApcMin/+ mice, voluntary exercise decreased the ratio of serum insulin like growth factor (IGF)-1 to IGF binding protein (BP)-3 levels. It also decreased prostaglandin E2 and nuclear β-catenin levels, but increased E-cadherin levels in the tumors.ConclusionThese results indicate hat voluntary exercise inhibited intestinal tumorigenesis in ApcMin/+ mice and AOM/DSS-treated mice, and the inhibitory effect is associated with decreased IGF-1/IGFBP-3 ratio, aberrant β-catenin signaling, and arachidonic acid metabolism.

Effect of Exercise on Cardiac Tissue Oxidative and Inflammatory Mediators in Chronic Kidney Disease

Background: Chronic renal failure (CRF) results in diminished physical activity and increased risk of cardiovascular disease (CVD). CVD risk factors are raised by sedentary life style and ameliorated by physical fitness in the general population. Accordingly, exercise improves hypertension, endothelial dysfunction, insulin resistance, dyslipidemia, inflammation and oxidative stress in high-risk populations. This study was designed to explore the effect of exercise on oxidative and inflammatory mediators in the left ventricle (LV) of CRF rats. Methods and Results: One week after 5/6 nephrectomy female rats were housed in either regular cages or cages equipped with running wheels for 4 weeks. Sham-operated rats housed in regular cages served as controls. Sedentary CRF rats exhibited azotemia, hypertension, anemia, oxidative stress, activation of NF-κB and upregulations of reactive oxygen species-generating enzyme, NAD(P)H oxidase, MCP-1, cyclooxygenase-2 (COX-2), and PAI-1 in LV. The CRF rats assigned to the exercise group ran 6.8 ± 0.7 km/day and 72 ± 8 min/day. Voluntary exercise reversed NF-κB activation and lowered NAD(P)H oxidase, PAI-1, MCP-1 and COX-2 abundance, increased LV mass by raising myofibrillar proteins and ameliorated anemia without affecting renal function or arterial pressure. Conclusions: CRF resulted in upregulation of prooxidant/proinflammatory pathways in LV. These changes were ameliorated by exercise, which indicates the potential cardiovascular benefit of exercise in renal insufficiency.

Prolonged Upright Posture Induces Degenerative Changes in Intervertebral Discs in Rat Lumbar Spine

Both forelimbs of rats were amputated, and these rats were kept in the custom-made cages that kept the rats in prolonged upright posture. Pathologic changes were observed in the lumbar spine at different time points after the surgery. To investigate the effect of upright posture on intervertebral discs of rat lumbar spine. Previous studies have shown that increased axial forces on the spine can decrease the height of the intervertebral disc, but there are no data to indicate whether or not long-term and repeated assumption of the upright posture could result in degenerative changes. The forelimbs of 30 rats were amputated when they were 1-month old. These rats were kept in the custom-made cages and were forced to stand upright on their hind-limbs and tails to obtain water and food. Normal rats of the same ages kept in regular cages were used as control. The rats were killed at 5, 7, and 9 months after the surgery, and the intervertebral discs samples of lumbar spine were harvested for histologic and immunohistochemical studies. Total RNA isolated from these samples was used for real-time PCR of type II collagen (Col2alpha1), type X collagen (Col10alpha1), matrix metalloproteinase-13 (MMP-13), aggrecan, and disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS-5). RESULTS.: Histologic analysis showed degenerative changes of the intervertebral discs after surgery such as disordered collagen structure of endplate cartilage, fragmentation of annulus fibrosus, and decreased height of disc. Immunostaining revealed decreased protein level of type II collagen and increased protein expression of type X collagen. Real-time PCR showed upregulated expression of MMP 13, ADAMTS-5, and Col10alpha1 mRNA and downregulated mRNA expression of Col2alpha1 and aggrecan. Long-term and repeated assumption of the upright stance accelerates disc degeneration in rats.

Effect of Exercise Training on Aortic Tone in Chronic Renal Insufficiency

Chronic renal insufficiency (CRI) is associated with a high incidence of hypertension (HTN), endothelial dysfunction, atherosclerosis and cardiovascular disease. Sedentary life style increases, whereas regular exercise reduces the risk of cardiovascular disease. This study was designed to test the effect of regular exercise on vasodilatory and vasoconstrictive responses of the thoracic aorta in rats with renal mass reduction. One week after 5/6 nephrectomy (CRI) or sham operation (control), rats were housed in either regular cages or cages equipped with running wheels for 4 weeks. Thereafter, thoracic aorta was harvested and contractile response to potassium and phenylephrine (PhE), and relaxation response to acetylcholine (ACh) and sodium nitroprusside (SNP) were determined. Compared with the control animals, sedentary CRI animals exhibited significant azotemia, proteinuria, HTN, oxidative stress, and increased sensitivity to potassium and PhE, and reduced sensitivity to ACh and SNP. Exercise training for 4 weeks reduced oxidative stress, reversed CRI-induced heightened sensitivity of the aorta to PhE and potassium, and restored its sensitivity to ACh (but not SNP) without affecting arterial pressure or renal function. CRI results in heightened sensitivity to potassium- and alpha-1 adrenergic-mediated contractility and depressed sensitivity to endothelium-dependent relaxation in the aorta. Regular exercise improves these abnormalities without affecting arterial pressure or renal function. These observations suggest that exercise training can improve vascular function in animals, and perhaps humans, with chronic kidney disease.

Effect of exercise training on endothelial function and vascular contractility in chronic kidney disease

Chronic renal failure (CRF) is associated with reduced physical activity, increased HTN, endothelial dysfunction, atherosclerosis and cardiovascular disease. Sedentary life style increases, whereas regular exercise reduces risk of cardiovascular disease in the general population. Study tested the hypothesis that aerobic exercise might improve arterial dysfunction in CRF rats. One week after 5/6 nephrectomy (CRF) or sham operation (control), rats were housed in regular cages or cages equipped with running wheels for 4 weeks. Thoracic aorta was harvested. Contractile response to potassium, phenylephrine, relaxation response to acetylcholine, sodium nitroprusside (SNP) and isoproterenol were determined. Compared to control animals, sedentary CRF animals exhibited significant azotemia, proteinuria, hypertension, increased sensitivity to potassium, phenylephrine, isoproterenol, reduced sensitivity to acetylcholine and sodium nitroprusside. Exercise CRF‐induced heightened sensitivity of aorta to phenylephrine and potassium, restored its sensitivity to acetylcholine without affecting arterial pressure or renal function. CRF results in heightened sensitivity to potassium‐ and alpha‐1 adrenergic mediated contractility and depressed sensitivity to endothelium‐dependent relaxation in aorta. Exercise training can improve vascular function in animals, and perhaps humans, with CKD.

Selecting high stability water clusters by examining locations of free OH bonds: Application in the study of [formula omitted] clusters

Computational studies on water clusters can be quite challenging, especially when an irregular cage with non-equivalent oxygen sites are considered which may yield a large number of starting geometries that differ in relative positions of non-H-bonding H (NHB H, free OH) atoms. A detailed study on water octamers suggests that the fewest number of NHB H atoms on neighboring oxygen sites yields the most stable neutral isomer followed by those with increasing number of NHB H atoms on adjacent sites. The least stable cluster has all the NHB H atoms around a ring. By considering a regular cage structure and minimum number of NHB H atoms on adjacent sites, one can readily identify a limited number of starting geometries that are optimized to highly stable isomers. This method has been verified in the identification of the most stable isomer of (H 2O) 8 cubic cage and (H 2O) 20 dodecahedral cage. The same method has been applied in the study of ( H 2 O ) 18 − cluster isomers.

Performance and behaviour of rabbit does in a group-housing system with natural mating or artificial insemination

This study compared reproductive performance and behaviour of does raised in a group-housing system and in a regular cage system. The group-housing pen was divided into different functional areas for suckling, resting, and eating and special hiding areas for kits when they had left the nest-boxes and does to favour the species specific behavioural traits. Does had access to their nest-box by means of an individual Electronic Nest-box Recognition System (ENRS) activated by a coded transponder placed in their eartags. Eight does were housed in each pen. Natural mating (NM, with a buck in the group) or artificial inseminations (AI) were applied. Litter size, kit mortality and kit weight at 14 d of age were similar for group-housing and cages when NM were applied. With a natural reproduction rhythm group-housing led to an increase of +38% of litters. However, from a management point of view, a cycled production system with AI is preferred. With AI and group-housing, a lower kindling rate and a lower kit weight at weaning were found. The lower kindling rate was partly caused by pseudo-pregnancies that were found in 23% (P < 0.01) of the does in the group-housing system against 0% in the control group. Sixteen to 20% of the does in the group-housing system had skin injuries, which is an indicator for aggression among does. Most of the injuries were seen on the body and most of them were superficial bites. Based on the results of this study, it can be concluded that group-housing of rabbit does seems possible, but more research is needed to solve the problems of the decreased kindling rate and occurrence of pseudo-pregnancies, the lower weight at weaning and aggressiveness among does.

Effect of flywheel-based resistance exercise on processes contributing to muscle atrophy during unloading in adult rats

Flywheel-based resistance exercise (RE) attenuates muscle atrophy during hindlimb suspension. We have previously shown that protein synthesis is elevated in response to RE, but the effect on protein degradation, cell proliferation, or apoptosis was not investigated. We hypothesized that, in addition to affecting protein synthesis, RE inhibits processes that actively contribute to muscle atrophy during hindlimb suspension. Male rats were housed in regular cages (control), tail suspended for 2 wk (HS), or HS with RE every other day for 2 wk (HSRE). Although RE attenuated soleus muscle atrophy during HS, the observed fivefold elevation in apoptosis and the 53% decrease in cell proliferation observed with HS were unaffected by RE. Expression of genes encoding components of the ubiquitin-proteasome pathway of protein degradation were elevated with HS, including ubiquitin, MAFbx, Murf-1, Nedd4, and XIAP, and proteasome subunits C2 and C9. Total ubiquitinated protein was increased with HS, but proteasome activity was not different from control. RE selectively altered the expression of different components of this pathway: MAFbx, Murf-1, and ubiquitin mRNA abundance were downregulated, whereas C2 and C9 subunits remained elevated. Similarly, Nedd4 and XIAP continued to be upregulated, potentially accounting for the observed augmentation in total ubiquitinated protein with RE. Thus a different constellation of proteins is likely ubiquitinated with RE due to altered ubiquitin ligase composition. In summary, the flywheel-based resistance exercise paradigm used in this study is associated with the inhibition of some mechanisms associated with muscle atrophy, such as the increase in MAFbx and Murf-1, but not with others, such as proteasome subunit remodeling, apoptosis, and decreased proliferation, potentially accounting for the inability to completely restore muscle mass. Identifying specific exercise parameters that affect these latter processes may be useful in designing effective exercise strategies in the elderly or during spaceflight.

Maternal separation affects cocaine-induced locomotion and response to novelty in adolescent, but not in adult rats

Maternal separation is known to exert long-term effects on both behavior and the neuroendocrine system. We investigated cocaine-induced locomotor activation as well as the locomotor and corticosterone response to forced novelty in maternally separated adolescent and adult rats. Maternal separation consisted of separating litters from their dams daily during 5 h from postnatal days 2 to 6. Control animals were subjected only to regular cage changes. Cocaine- (10 mg/kg, i.p.) and novelty-induced locomotion were recorded in an activity cage. After the animals were tested for behavioral response to novelty, trunk blood samples were collected and plasma corticosterone levels were determined by radioimmunoassay. Adolescent rats exposed to maternal separation exhibited an increased locomotor response to novelty and cocaine; corticosterone levels were lower in these adolescent animals, after exposure to the novel environment. These effects of maternal separation were not observed in rats that were tested as adults. Thus the maternal separation protocol produced enduring but transient changes in the behavioral response to cocaine and in the stress response to novelty.