Age-related changes of the mossy fibre system in rat hippocampus: effect of long term acetyl-L-carnitine treatment.

Age-related changes of the hippocampal mossy fibre system were studied in rats of different ages (4, 12, and 24 months) using the Timm's histochemical technique for the detection of tissue stores of zinc and heavy transitional metals. Quantitative image analysis and microdensitometry techniques were applied for the evaluation of the changes themselves. The area occupied by mossy fibres and the intensity of Timm's staining in field CA3 of hippocampus were greater in adult rats than in young and old animals. These findings are consistent with previous behavioural data indicating that young and old rats exhibited a reduced passive avoidance learning with respect to adult animals. The above techniques were also used in a second session of this study designed to investigate the effect of a 6-months treatment with acetyl-L-carnitine (ALC) on the hippocampal mossy fibre system. ALC was found to increase significantly the area occupied by mossy fibres and the intensity of Timm's staining in the hippocampus of old rats. These findings are in agreement with and support from an anatomical point of view, the data indicating that long-term treatment with ALC improves passive avoidance performance

Different in vitro response to rIL-1β of newborn and adult rat astroglia

http://sfx.cilea.it:9003/sfxcab3/sf(opens in a new window)|View at Publisher| Export | Download | Save to list | More... International Journal of Developmental Neuroscience Volume 9, Issue 5, 1991, Pages 501-507 Different in vitro response to rIL-1β of newborn and adult rat astroglia (Article) Colasanti, M.a, Ramacci, M.T.b, Foresta, P.c, Lauro, G.M.a a Dipartimento di Biologia Cellulare e dello Sviluppo, Università La Sapienza, Via degli Apuli, 1-00185 Roma, Italy b Istituto per la Ricerca sulla Senescenza. SIGMA-TAU, Pomezia, Italy View references (17) Abstract In recent literature, lymphokines have been reported to be able to promote both proliferation and maturation of some glial populations. In this paper, we compare the effect of rIL-1 on newborn and adult rat astroglial cells in vitro. In newborn, but not in adult astrocytes, 100 U/ml of rIL-1β increase [3H]thymidine incorporation with a maximal response by 3 days as compared to the control untreated culture. In contrast, rIL-1β induces an increase of GFAP immunoreactivity both in newborn and in adult astrocytes, as compared to the control untreated cells. These data indicate that, while both newborn and adult astroglial cells are capable of responding to rIL-1β, only newborn astrocytes can respond to this lymphokine with proliferation. Thus, it appears likely that different factors, other than rIL-1β, are needed by adult astrocytes to proliferate

Age-dependent nerve cell loss in the brain of Sprague-Dawley rats: effect of long term acetyl-L-carnitine treatment.

The age dependent loss of nerve cells was investigated in 22 brain areas from young (3 month), adult (13 month) and old (25 month) Sprague-Dawley rats. As in previous studies, we observed an age-related neuronal loss primarily in the archicortex and in the hippocampus and in other subcortical structures (amigdaloid nucleus, pontine nuclei, cerebellar cortex). In sensory areas of cerebral cortex the neuronal loss was less marked. The effect of a 6 month treatment with acetyl-L-carnitine (ALCAR) on the number of nerve cells in the same brain areas was also investigated. ALCAR treatment began when the rats were aged 16 months. ALCAR treatment was able to counteract the age-dependent decrease in nerve cell number primarily in the temporal and occipital cortical areas, in the archicortex and hippocampus. The above findings suggest that long term ALCAR treatment may be effective in slowing down the age-related nerve cell loss in some rat brain areas

Reduced lipofuscin accumulation in senescent rat brain by long-term acetyl-L-carnitine treatment.

By using fluorescence microscopy and microfluorimetric techniques, the effects of ageing and of 11 months acetyl-L-carnitine (ALCAR) treatment on lipofuscin deposition within the cytoplasm of pyramidal neurons of rat prefrontal cortex and hippocampus (CA3 field) were assessed. No lipofuscin autofluorescence was observed in the nerve cell bodies of neurons under study in young rats (3 months of age), but lipopigment had accumulated in the same nerve cells of senescent rats (22 months of age). ALCAR administration significantly reduced the accumulation of lipofuscin within pyramidal neurons of the brain areas examined

Age-dependent increase of rabbit aortic atherosclerosis. A morphometric approach

Aging has been indicated as one of the major risk factors for development of atherosclerotic lesions, although the role aging plays, lacks accurate evaluation. Our study was aimed at quantitatively defining such a role by using morphometric analysis. Aged (median age 3 years and 8 months) and young (4 months) white New Zealand rabbits received a hyperlipemic diet enriched with a low dose of cholesterol for 16 months. At regular intervals, levels of serum lipemic parameters were checked. A Quantimet 920 image analyzer was used on paraffin-embedded sections of the entire aortas to measure the volume density of the tunica intima, the volume density of atheroma, the ratio intima/media and the surface area of the tunica intima. Our results indicated for aged hyperlipemic rabbits a statistically significant increase in all morphometric parameters examined as compared to young hyperlipemic animals, and no statistically significant differences in serum cholesterol, triglycerides and phospholipids

Acetyl-L-carnitine reduces the age-dependent loss of glucocorticoid receptors in the rat hippocampus: an autoradiographic study.

Brain autoradiography in adrenalectomized rats injected with 3H-corticosterone 2 hr before sacrifice was used to study the effect of aging and long-term acetyl-l-carnitine treatment on the hippocampal glucocorticoid receptor. Densitometric analysis of silver grains in individual nerve cells of the hippocampus showed that pyramidal neurones of the CA1 field and granular cells of the dentate gyrus are richest in 3H-corticosterone binding sites, whereas pyramidal neurons of the CA3 field have the lowest number of binding sites. There was a significant decline in the number of glucocorticoid receptors within the various hippocampal areas, both as the total number of 3H-corticosterone binding sites and as the number per single pyramidal or granule neuron associated with aging and perhaps due to loss of adrenocorticoid-competent neurons. The dentate gyrus and the CA1 region were mostly affected by the age-dependent decrease in glucocorticoid receptors of the hippocampus. Twenty-eight-month-old rats, treated with acetyl-l-carnitine for 7 months, showed a significantly higher number of 3H-corticosterone binding sites within the various hippocampal regions examined than did age-matched controls. The CA1 and the dentate gyrus were the regions most susceptible to amelioration by acetyl-l-carnitine treatment. These findings suggest a positive effect of acetyl-l-carnitine treatment on age-related changes which occur in the hippocampus

Propionyl-L-carnitine prevents the progression of atherosclerotic lesions in aged hyperlipemic rabbits

We have characterized the extent and the phenotype of total and proliferating cell-population of aortic plaques in aged rabbits receiving a long-term low-dose cholesterol hyperlipemic diet, which represents an experimental model of atherosclerosis. For nine months, rabbits received the hypercholesterolemic diet alone or in addition to a treatment with propionyl-L-carnitine (PLC), a derivative of carnitine, an intramitochondrial carrier of fatty acids present in most cell types. We observed that, in both PLC-treated and control hyperlipemic rabbits, the ratio between proliferating macrophage-derived and smooth muscle cells was 2:1. PLC in addition to the hypercholesterolemic diet induced a marked lowering of plasma triglycerides, very low density lipoprotein (VLDL) and intermediate density lipoprotein (VLDL) triglycerides, while plasma cholesterol was slightly and transiently reduced. Moreover, PLC-treated hyperlipemic rabbits exhibited a reduction of plaque thickness and extent, a slight but significant reduction of the percentage of macrophage-derived cells as compared to control hyperlipemic animals and a reduction of the number of both proliferating macrophage- and smooth muscle cell-derived foam cells. Finally, both proliferating and non-proliferating plaque cells expressed large amounts of macrophage colony-stimulating factor protein, in particular macrophage-derived foam cells. These results indicate that a modification of plasma lipemic pattern obtained by a long-term oral administration of PLC was associated with a decrease of plaque cell proliferation and severity of aortic atherosclerotic lesions