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Biomedical subjects

Andrus Viidik

Publications and source records attributed to Andrus Viidik.

16 recordsLinked to original sources
PubMed2006

The impact of environment in comparison with moderate physical exercise and dietary restriction on BDNF in the cerebral parietotemporal cortex of aged Sprague-Dawley rats.

BACKGROUND AND AIMS: Moderate physical exercise, dietary restriction as well as enriched environment in separate studies have been reported to delay some of the adverse effects of aging on brain function, parallel to an increase in brain-derived neurotrophic factor (BDNF). In order to elucidate these influences in a comparative setting, we examined the tissue concentrations of BDNF in the cerebral parietotemporal cortex of old Sprague-Dawley rats. METHODS: Male Sprague-Dawley rats were divided randomly into six groups, living from 5 months (baseline group BL) up to 23 months of age as follows: voluntary running in wheels (RW), food restricted by feeding to pair weight with RW animals (PW), forced running on treadmills (TM), and sedentary controls with ad libitum access to food, either housed individually (S1) or in groups of 4 animals (S4). BDNF concentrations were determined by a commercially available ELISA. RESULTS: We found higher BNDF concentrations in the 5 months old animals than in the 23 months old animals of group S1. The old sedentary group S4 showed significantly higher BNDF concentrations in comparison with the old individually caged groups RW, TM, PW and S1. Their BNDF concentrations were even higher than those of the young baseline group. CONCLUSIONS: Our data suggest that housing and social interactions have more influence on BDNF concentrations in the cerebral parietotemporal cortex of aging Sprague-Dawley rats than physical exercise and food restriction.

Age Factors↗
PubMed2006

Impact of moderate physical exercise--in comparison with dietary restrictions--on age-associated decline in cell-mediated immunity of Sprague-Dawley rats.

BACKGROUND AND AIMS: Moderate physical exercise and dietary restriction have both been demonstrated to delay some of the adverse effects of aging. In order to elucidate similarities or dissimilarities in their mode of action on the aging immune system in a comparative setting, we examined significant parameters of cell-mediated immunity in Sprague- Dawley rats. METHODS: Male Sprague-Dawley rats, housed individually, were divided into four groups, living from 5 months (baseline group BL) up to 15, 19 and 23 months of age as follows: voluntary running in wheels (RW), food restricted by feeding to pair weight with RW animals (PW), forced running on treadmills (TM), and sedentary controls with ad libitum access to food (S1). White blood cell counts, capacity for lymphocyte proliferation in response to Concanavalin A, and interleukin-2 (IL-2) plasma concentrations were determined. RESULTS: White blood cell counts and the cell numbers of lymphocytes, neutrophil and eosinophil granulocytes were significantly lower in the older RW and PW groups. We observed influences of forced exercise on lymphocyte proliferation: blastogenic reactivity was higher in TM animals compared with RW and PW animals at 23 months of age. Exclusively for RW animals, we found lower plasma concentrations of IL-2 at 23 months. CONCLUSIONS: Our data support the idea that moderate physical exercise modulates age-associated decline in the cell-mediated immunity of old Sprague-Dawley rats significantly more than corresponding dietary restrictions.

Aging↗
PubMed2005

Impairment of water maze behaviour with ageing is counteracted by maze learning earlier in life but not by physical exercise, food restriction or housing conditions.

Spatial learning and memory decline with ageing in humans as well as rats. We examined the influence of different interventions on male Sprague Dawley rats with respect to learning ability and memory at the age of 5, 10 and 18 months. The intervention and control groups were: (RW) voluntary exercise in running wheels, (PW) sedentary, food restricted (by about 25%) to keep them at pair weight with RW, (S1) sedentary, fed ad libitum, (TM) forced training in a treadmill, and, (S4) sedentary, fed ad libitum. The animals in all groups were housed individually except those in group S4, which were housed four in each cage. The ability of learning and memory was determined in the Morris water maze. The results showed a significantly better learning ability when young in comparison with their ability when having grown older. At the age of 18 months, the performance was significantly better in the subgroups which had received training also at the age of 10 months compared to the subgroups receiving their first training. None of the various interventions had any significant effect on these functions. Repeated training seems to be the best intervention with respect to retaining learning ability and memory.

Aging↗
PubMed2005

The effect of chronic physical exercise on succinic dehydrogenase activity in the heart muscle of old rats.

Succinic dehydrogenase (SDH) activity, preferentially evidenced by cytochemical methods, has been measured by computer-assisted morphometry in the heart muscle of old sedentary and age-matched animals chronically undergone physical exercise (20 min, twice a day, 5 days a week). The area of the SDH-positive mitochondria (MA) and the overall area of the cytochemical precipitates due to SDH activity (PA) were semiautomatically measured and the ratios PA/MA as well as MA/overall myocardial tissue area analysed (MA/TA) were the parameters taken into account. No significant difference was found between the two groups investigated as regards PA/MA, whereas the MA/TA value is significantly increased in the animals undergone physical training. The present findings document that chronic physical exercise significantly increases the overall mitochondrial area involved in energy provision in the old myocardial tissue. Considering that myocardial function highly relies on mitochondrial metabolism, our results support a beneficial effect of chronic physical exercise on the old heart muscle.

Aging↗
PubMed2004

Effects of life-long exercise on circulating free fatty acids and muscle triglyceride content in ageing rats.

Regular physical exercise has emerged, together with dietary restriction, as an effective intervention in delaying degenerative diseases and augmenting life span in rodents. The mechanisms involved remain largely unknown, although a beneficial influence on the age-related alteration of insulin sensitivity has been hypothesized. As muscle triglyceride (TG) accumulation is considered a reliable index of muscle insulin resistance, in this study we explored muscle TG content in 23-month-old male Sprague-Dawley rats subjected to life-long training. Plasma glucose, insulin, free fatty acid (FFA) and leptin levels were also measured. Both voluntary running in wheels (RW) and forced training in treadmill (TM) were studied. As RW rats weighed less than controls, a cohort of untrained animals, fed to pair weight (PW) with RW, was added to discriminate the effect of exercise from that of food restriction. Sedentary ad libitum fed rats served as controls. In 23-month-old RW rats, muscle TG content was reduced by 50% with respect to age-matched sedentary controls, while in TM group this reduction was smaller but still highly significant, and occurred independently on the changes in body fat mass. In both the trained rat groups, there was a significant decrease in circulating FFA levels and a trend to reduced insulin levels. In PW rats, muscle TG levels decreased similarly to RW rats, while plasma parameters were less modified. In particular, RW training was more effective than PW in preventing the age-related increase in circulating leptin levels. Our results suggest that voluntary exercise effectively counteracts the development of insulin resistance in the muscles of ageing rats as well as other related changes such as hyperlipacidaemia and compensatory hyperleptinaemia. Forced training or moderate food restriction appear slightly less effective than voluntary exercise in preventing age-dependent alterations in nutrient distribution and/or utilization.

Adipose Tissue↗
PubMed2004

Is there an association between rumination and self-reported physical health? A one-year follow-up in a young and an elderly sample.

Cross-sectional studies have suggested an association between rumination and subjective health. The aim of the present study was to investigate in a longitudinal design whether rumination was related to self-reported physical health. A total of 96 young (age range 20-35) and 110 elderly (age range 70-85) participants completed questionnaires measuring rumination, negative affect, life events, and self-reported physical health at baseline and at 1-year follow-up. Multiple linear regressions showed a significant association between self-reported physical health at time I only for the elderly and negative affect mediated the association. At follow-up, rumination was significantly associated with self-reported physical health only for the young and the association was only partly mediated by negative affect. In conclusion, rumination is associated with poorer self-reported physical health, but the association depends on the age of the individual as well as time span studied.

Adaptation, Psychological↗
PubMed2003

Voluntary exercise and mild food restriction effectively retard the collagen biomarker of aging.

BACKGROUND AND AIMS: Obesity and lack of physical exercise characterize increasing numbers of people in Western societies, resulting in increasing morbidity and mortality. Regular physical exercise, on the other hand, has been shown to be beneficial. Beneficial effects have also been shown in laboratory rodent studies--lifelong physical exercise increases the mean life span but not the maximum life span, while food restriction increases both life spans. We studied male Sprague-Dawley rats in order to further analyze these beneficial effects. METHODS: We compared voluntary running in wheels (RW) with food restriction to pair weight with RW (PW), and mild forced running in treadmill (TM)--all animals housed individually. Control groups were sedentary ad libitum-fed animals housed individually (S1) and four to a cage (S4). The collagen biomarker of aging was calculated as a composite parameter from thermal stability data for 5 (baseline), 15, 19 and 23 months of age. RESULTS: In RW and PW, the increase in the composite parameter was retarded to the same extent. The retardation in TM was less efficient. S4 had the highest value for the composite parameter, together with the highest body weight and fat content. In groupwise comparisons, the composite parameter tended to predict survival in the groups up to the age of 23 months. CONCLUSIONS: Voluntary running in wheels is more beneficial than mild-forced exercise on the treadmill. The composite parameter is a useful indicator of different interventions on aging rats.

Aging↗
PubMed2002

Polarized light microscopic analyses of collagen fibers in the rat incisor periodontal ligament in relation to areas, regions, and ages.

We prepared decalcified sagittal sections (20 microm thick) from the incisal, middle, and basal regions of the mandibular incisor of male Wistar rats aged 2, 6, 12, and 24 months, and examined the sections using polarized light microscopy. Most of the birefringent fibers appeared to run obliquely across the periodontal ligament. Birefringent fibers running parallel to the long axis of the incisor were also found in the intermediate area of the ligament. Similar fiber architecture was observed in all four age groups. Quantitative analysis showed that the retardation values of collagen were higher in the bone- and tooth-related areas and lower in the intermediate area of the ligament. The values for the bone- and tooth-related areas increased from the basal toward the incisal regions in all four age groups. Age-related changes in the retardation values were found only in the incisal region of the incisor. In the incisal region, the values for the bone- and tooth-related areas increased markedly from 2-24 months of age, whereas those for the intermediate area increased slightly but significantly with age. Our findings indicate that the degrees of molecular organization and alignment of collagen fibers in the bone- and tooth-related areas of the ligament are higher than those in the intermediate area and increase near the incisal region and with age. It is also suggested that the collagen fibers in the intermediate area remain immature along the long axis of the incisor throughout the life span of the animal.

Age Factors↗
PubMedDate not supplied

Negative thoughts and health: associations among rumination, immunity, and health care utilization in a young and elderly sample.

OBJECTIVE: In the present study, it was tested whether rumination-negative, recurrent thoughts-would be associated with immune parameters and health care utilization. Because rumination has been associated with sadness and subjective sleep quality, it was tested whether these factors mediated the possible effects of rumination. A young sample and an elderly sample were included to test for age differences in the association between rumination and health-related measures. METHODS: A representative sample of 196 young subjects (20 to 35 years) and 314 elderly subjects (70 to 85 years) completed questionnaire measures of rumination, sadness, and subjective sleep quality. Immune measures included leukocyte counts, lymphocyte subsets, natural killer cell activity, and T-cell proliferation. Contacts with primary care physicians were registered for 1 year through central registers. RESULTS: Rumination displayed a positive association with total leukocyte count, total lymphocyte count, and number of B cells among the elderly, and this was not mediated by sadness or subjective sleep quality. Rumination was also positively associated with number of telephone consultations during the follow-up for the elderly, and this was partly mediated by sadness and subjective sleep quality. Although total leukocyte counts correlated with number of telephone consultations at the follow-up, none of the immune parameters mediated the association between rumination and health care utilization. No significant associations were found for the young participants. CONCLUSION: The results suggest that rumination may be associated with health-related measures in the elderly. Thus, negative thoughts may be detrimental to health, independently of negative affect.

Adaptation, Psychological↗
PubMedDate not supplied

Physical exercise retards the development of chronic nephropathy in the ageing rat as efficiently as food restriction does.

BACKGROUND: Obesity combined with decreasing physical fitness in the ageing Western populations promotes a number of degenerative diseases, including chronic kidney disease. It has further been shown in rodent models that prevention of obesity by food restriction mitigates development of kidney lesions. Whether lifelong physical activity also has a positive effect is not known. OBJECTIVE: To compare the effects of physical exercise and food restriction on the development of chronic kidney lesions in ageing rats. METHODS: Male Sprague-Dawley rats were divided into groups: voluntarily running in wheels (RW), food restriction to the degree necessary to attain pair weight to RW rats (PW), forced running in treadmills (TM) and sedentary controls housed individually (S1) or 4 in each cage (S4). The interventions began at the age of 5 months and kidneys were sampled and analysed histologically at the ages of 15, 19 and 23 months. RESULTS: Total score for kidney lesions (sum of the scores for glomerular changes, interstitial non-purulent inflammation, proteinaceous casts in tubules and increased amount of connective tissue, the possible maximum being 10.0) increased from 0.5 +/- 0.2 at 5 months of age to 1.6 +/- 0.3 for RW, 2.3 +/- 0.4 for PW, 4.5 +/- 0.4 for TM, 3.6 +/- 0.5 for S1 and 5.4 +/- 0.6 for S4 at the age of 23 months. The increase from 5 months of age was gradual for all groups through 15, 19 and 23 months. The patterns for the various lesions followed the same pattern with the exception of connective tissue, which did not increase. CONCLUSION: Voluntary running in wheels is as effective in mitigating kidney lesions as is food restriction, while forced running in a treadmill is not effective in this respect.

Aging↗