[The myoid body of the retina: immunochemical analysis].
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
N Pescosolido
Publications and source records attributed to N Pescosolido.
Age-related changes in rat retina.
PURPOSE: To describe the changes in rat retina occurring with ageing by means of histological methods, scanning electron microscopic observations and morphometrical data; and to study by means of biochemical methods the amount of protein content in retinal tissues. METHODS: Samples of fresh retinal tissue obtained from young, adult, and aged rats were studied by means of traditional histological methods and by scanning electron microscopy. Particular attention was paid to morphometrical data and to the changes which occur with ageing. With the aid of a quantitative analysis of images, a large amount of morphometrical data was collected. Moreover, the amount of protein content in retinal tissues has been determined. RESULTS: Retinal thickness significantly decreases with age. The ganglion cells seem to be more vulnerable to age-related loss than other retinal cells. The number of retinal capillaries is diminished with age. The intercellular connections between photoreceptors, the number of cellular processes, and the number of synaptic bodies of the bipolar cells also decrease significantly with age. These results were all confirmed by scanning electron microscopy observations and morphometrical findings. Biochemical dosage of proteins demonstrates that retinal tissues decrease with age. CONCLUSIONS: All morphological, morphometrical, ultrastructural and biochemical data are concordant in demonstrating that the retinal tissues of rats undergo specific changes with age. Our findings are in agreement with those described by previous authors and underline that the rat retina can be considered an optimal model for studies on neuronal maturation and/or neuronal ageing. Since our data have confirmed that many changes occur in rat retina with ageing, we can hypothesize that rat retina is particularly sensitive to developmental changes and to senile decay.
Aging↗
Uveoscleral outflow in dog's eye: role of several enzymes.
The morphological pattern of several enzymes (succinic dehydrogenase--SDH, glucose-6-phosphate dehydrogenase--G6PDH and lactic dehydrogenase--LDH) was evaluated in normal dog eyes. Special attention was paid to the uveo-scleral tissue. Cryostatic sections of dog eye were stained with toluidine blue for the recognition of the microanatomical details or with histoenzymatic methods for SDH, G6PDH and LDH activities using sodium succinate, glucose-6-phosphate and sodium lactate as substrates respectively, nicotinamide adenine dinucleotide (NAD) as a reducing agent and sodium nitro-blue-tetrazolium as a colouring substance. A moderate positive reaction for SDH and a strong positive reaction for LDH were observed in the uveoscleral tissue, while G6PDH gave negative staining. Some considerations regarding a possible active role of these enzymatic activities to the aqueous humor outflow are suggested.
Animals↗
A morphometric study of age changes in the rat optic nerve.
Age-related changes of the optic nerve fibres were studied in 3-month-old (young), 12-month-old (adult) and 24-month-old (aged) male Sprague-Dawley rats. The optic nerve was harvested with particular care from the intracranial portion. Cross sections from the optic nerve of animals of different age groups were stained with toluidine blue and examined under a light microscope at low and high magnification. Other sections were stained for the demonstration of glial cells using the method described by Holzer. A third group of sections were stained by the immunohistochemical method to detect glial fibrillary acidic protein, which is a marker for localising and characterising astrocytes. All these morphological results were subjected to the quantitative analysis of images and to statistical analysis of the values to identify significant morphometric data. Biochemical dosages of proteins were also performed on homogenised fragments of the optic nerve. Our results demonstrate that the following age-related changes can be observed: (1) an increase in meningeal membranes, (2) an increased number of astrocytes, (3) an increase in areal density of glial fibrillary acidic protein immunoreactivities, (4) an increased thickness of the entire optic nerve and an increased area of the nerve, (5) a decreased number of nerve fibres and (6) a decrease in the nerve fibre/meningeal membrane ratio from 3:1 to 1:1. Moreover, the amount of protein does not change with age. The rat optic nerve, therefore, appears sensitive to aging processes.
Aging↗
Metabolic changes in rabbit lens induced by treatment with dexamethasone.
Metabolic changes in the rabbit lens have been studied by means of nuclear magnetic resonance spectroscopy. These changes have been induced by prolonged topical treatment with dexamethasone. Our results demonstrate an increase in sorbitol, sorbitol-3-phosphate, fructose-3-phosphate, glycerol-3-phosphate and glucose-6-phosphate levels and a decrease in glutathione sulphate (GSH) and myo-inositol levels, in agreement with what was observed in lenses from streptozocin-diabetic rats before lens opacity. The hyperglycaemia can only partially explain all these observed biochemical variations. The lack of increase in the intermediates of pentose cycle, such as sedoheptulose-7-phosphate, seems to support the hypothesis of an inhibition of glucose-6-phosphate dehydrogenase by dexamethasone treatment. Finally dexamethasone treatment induces a decrease in GSH. The decreasing or the loss of GSH has been suggested as a possible pathogenic mechanism in the cataract formation.
Administration, Topical↗