Effect of acute pentylenetetrazol injection induced epileptic seizures on rat dentate gyrus at different postnatal ages / 대한해부학회지

Epilepsy is one of the most common neurological disorders, its prevalence approximately from 0.5% to 2% of the general population. Generalized seizures could lead to several morphological changes in the brain. This study aimed to investigate the morphological effects of a single convulsive dose of pentylenetetrazol (PTZ) on rat dentate gyrus at different postnatal ages. Thirty-six male Wistar rats were used at the following postnatal ages: P10, P21, and P90 (12 rats per each age). The animals in each age were equally divided into two groups: group I, control and group II, treated with a single intraperitoneal injection of PTZ (55 mg/kg). After confirmation of generalized tonic-clonic seizures, specimens from the right dentate gyrus were processed for light and electron microscopy. In PTZ-treated groups, the number of granule cells significantly decreased. Dark granule cells appeared in the deep layers of the granule cells in P10 and with the progress of age, they significantly increased in number and extended into the superficial layers of the granule cells. The dendritic spines diminished. Glial fibrillary acidic protein and caspase-3 expression increased. Ultrastructurally, granule cells showed irregular shaped nucleus, dilated rough endoplasmic reticulum (RER) cisternae, mitochondria with damaged cristae, large vacuoles, lysosomes, and lipofuscin granules. Dark granule cells characterized by electron-dense nucleus and cytoplasm containing disorganized Golgi bodies, swollen mitochondria with damaged cristae, numerous free ribosomes and few long strands of RER. Astrocytes had hypertrophied cell body. Acute treatment with PTZ-induced epileptic seizures caused toxic effect on the structure of rat dentate gyrus at different postnatal ages.

Effect of acute pentylenetetrazol injection induced epileptic seizures on rat dentate gyrus at different postnatal ages / 대한해부학회지

Epilepsy is one of the most common neurological disorders, its prevalence approximately from 0.5% to 2% of the general population. Generalized seizures could lead to several morphological changes in the brain. This study aimed to investigate the morphological effects of a single convulsive dose of pentylenetetrazol (PTZ) on rat dentate gyrus at different postnatal ages. Thirty-six male Wistar rats were used at the following postnatal ages: P10, P21, and P90 (12 rats per each age). The animals in each age were equally divided into two groups: group I, control and group II, treated with a single intraperitoneal injection of PTZ (55 mg/kg). After confirmation of generalized tonic-clonic seizures, specimens from the right dentate gyrus were processed for light and electron microscopy. In PTZ-treated groups, the number of granule cells significantly decreased. Dark granule cells appeared in the deep layers of the granule cells in P10 and with the progress of age, they significantly increased in number and extended into the superficial layers of the granule cells. The dendritic spines diminished. Glial fibrillary acidic protein and caspase-3 expression increased. Ultrastructurally, granule cells showed irregular shaped nucleus, dilated rough endoplasmic reticulum (RER) cisternae, mitochondria with damaged cristae, large vacuoles, lysosomes, and lipofuscin granules. Dark granule cells characterized by electron-dense nucleus and cytoplasm containing disorganized Golgi bodies, swollen mitochondria with damaged cristae, numerous free ribosomes and few long strands of RER. Astrocytes had hypertrophied cell body. Acute treatment with PTZ-induced epileptic seizures caused toxic effect on the structure of rat dentate gyrus at different postnatal ages.

possible protective effect of exercise on liver damage following hind-limb ischemia reperfusion injury in the adult male albino rat: light and electron microscopic study

Hind-limb ischemia-reperfusion [I/R] injury is not limited to the lower extremities; it also causes damage to remote organs. This study was undertaken to investigate the role of exercise in attenuating remote hepatic damage following hind-limb I/R injury. Forty-five adult male rats were divided into three groups: the control group, the I/R group, and the exercise+I/R group. The rats were left to swim for 1 h, five times a week, for 4 weeks before I/R. Bilateral hind-limb ischemia was induced by application of rubber bands above the greater trochanter for 3 h. Blood samples were taken after 3 h of reperfusion for determination of malondialdehyde, superoxide dismutase, tumor necrosis factor-alpha, and interleukin-6. Liver specimens were processed for light and electron microscopic study. In the I/R group, the superoxide dismutase level decreased and plasma levels of malondialdehyde, tumor necrosis factor-alpha, and interleukin-6 significantly increased when compared with the control group. Light microscopic examination showed hepatocytes with vacuolated cytoplasm, dilated blood sinusoids, and portal vessels. An extensive amount of collagen fibers around portal tracts and intense immune reaction for caspase-3 were observed. The ultrastructure showed hepatocytes with swollen mitochondria and disrupted cristae and others with an electron-dense matrix. Kupffer cells showed apoptotic bodies. Ito cells appeared surrounded by wide areas of collagen fibers. The exercise+I/R group showed significant attenuation of the biochemical and histological alterations of I/R-induced liver injury. Exercise could attenuate remote liver damage following hind-limb I/R injury

study on the postnatal development and aging changes of the neurosecretory nuclei of the hypothalamus [supraoptic and paraventricular nuclei] in the albino rat

The hypothalamus is a distinct neurological entity concerned with a variety of regulatory processes. Recently, the prescence of variations in the level of neurosecretions wth the progress of age was reported. To study the changes in the structure of magnocellular neurons in the paraventricular and supraoptic nuclei during the period of postnatal development. Furthermore, to study the changes which occurred in the structure of these neurons in the old age had been studied. A total of 52 albino rats were used. The age groups of the animals include: one day, 10 days, 20 days, 2 months and 2 years old animals. Brains were processed to be studied with Einarson's gallocyanin-chrome alum stain, Golgi- Cox method and transmission electron microscope. In addition, the number of cells in the magnocellular part of the paraventricular and supraoptic nuclei were measured in all studied age groups and statistically analyzed. In the newly born rats, the paraventricular and supraoptic nuclei were composed of small rounded condensed cells. At the age of 10 days old rats, the paraventricular nucleus appeared to be well differentiated into ventromedial [parvocellular] and dorsolateral [magnocellular] parts. With the progress of age from 10 days up to the adult stage, the cells of the supraoptic nucleus and the magnocellular part of the paraventricular nucleus appeared to be densely stained which indicated increase in the Nissl granules. Ultrastructural study showed that the cells had abundant amount of free ribosomes, rough endoplasmic reticulum and mitochondria. The nucleus had fine dispersed chromatin. Golgi-Cox study showed marked increase in extension and branching of dendrites with the progress of age during the developmental period. Morphometric study showed significant increase in the number of cells from the new born up to the adult stage. In old aged rats, the cells of the paraventricular nucleus and the supraoptic nucleus appeared to be faintly stained. Some cells had vacuolated cytoplasm. Ultrastructural study showed marked decrease in the free ribosomes and the presence of many lipofuscin pigment in the cytoplasm of cells. The nucleus showed chromatin condensation and irregularity of the nuclear membrane. In addition, there was apparent decrease in the amount of the synaptic vesicles in the presynaptic terminals making contacts with the magnocellular neurons. Golgi-Cox study revealed marked decrease in the extension and branching of dentrites. Morphometric analysis showed significant decrease in the number of cells. This study demonstrated in the presence of structural changes in the magnocellular part of the paraventricular nucleus and supraoptic nucleus during the period of development. In old age, the presence of many degenerative changes was observed. This cytoarchitectonic analysis and morphological study could help in the explanation of the functional differences in the various ages

Sex differences in dopaminergic neurons of substantia nigra pars compacta of adult and aged rats: a histological and immunohistochemical study

Substantia nigra pars compacta [SNC] is the main source of dopaminergic [DA] input to the striatum. Parkinson's disease is a neurodegenerative disease affecting DA neurons in SNC, with a higher incidence in men. To study the effect of sex on the structure of DA neurons in adult and aged rat SNC. The brains of 22 adult [11 males and 11 females] and 22 aged [11 males and 11 females] albino rats were processed for histological and immunohistochemical examination of DA neurons in the right SNC. Golgi-Cox staining of adult male SNC neurons showed more varicosities and less extension of their dendrites than adult female SNC. Adult male SNC showed a nonsignificant increase in tyrosine hydroxylase-positive neurons than adult female SNC. Aging-related changes were more marked in aged male rats. Aged SNC showed decreased packing density of neurons, some of which appeared irregular and deeply stained. A reduction in Nissl staining was observed. Golgi-Cox staining showed a marked decrease in extension and branching of the dendrites with loss of spines. Ultrastructurally, accumulation of lipofuscin pigment, membranous whorls, dilated Golgi bodies, decreased rough endoplasmic reticulum, and destroyed cristae of mitochondria were observed. A significant reduction in tyrosine hydroxylase-positive neurons was evident in aged SNC. Sex differences in DA neurons of SNC were more apparent in aged rats, with more degenerative changes in the aged male group, which may underlie the predisposition of males to Parkinson's disease

histological study on the effect of prenatal and postnatal administration of monosodium glutamate on the developing renal cortex of male albino rats

Monosodium glutamate [MSG] is a widely used flavour enhancer. Its use in high concentration could affect vital functions, including those of the kidney. The present study is concerned with evaluation of the effect of prenatal and postnatal MSG administration on the developing male albino rat renal cortex. Twenty pregnant female albino rats were divided into two equal groups: group I [control] and group II [treated]. In group II, MSG was administered orally at a dose of 2 mg/kg/day from the 12th day of gestation until the 21st day postnatally. After delivery, the offspring of both groups were sacrificed at the newborn stage, at 3 weeks and at 3 months. Kidney specimens were processed for examination by light and scanning electron microscopy. Maternal MSG administration affected both the renal glomeruli and tubules of the offspring. In the newborn stage, the glomeruli at the subcapsular zone appeared immature and crowded. The foot processes showed apparent elongation and disruption of their interdigitations. In weaned rats, apparent widening of Bowman's space in some glomeruli, detachment of podocytes and effacement of foot processes were noticed. In adult rats, the glomeruli showed hypercellularity with apparent elongation and fusion of the foot processes. The renal tubules at the different ages studied showed degenerative changes with sloughs inside the lumen of some tubules accompanied by proliferative changes. The proximal tubules showed partial loss of the brush border. MSG causes a delay in the development of glomeruli. Some glomeruli showed hypercellularity with affection of podocytes, which makes the glomeruli liable to glomerulosclerosis

Postnatal developmental and aging changes of the mammillary body in the albino rats [histological and ultrastructural study]

The mammillary body is the most prominent structure in the caudal hypothalamus of rats as it is involved in a variety of associative and memory processes. The aim of this study was to throw light on the postnatal developmental and aging changes of the mammillary body nuclei in the rat. A total number of 65 albino rats were used in this work. The age groups of the animals included new born, fifteen days, one month, two months and two years old rats. Specimens were processed for ordinary histological study and stained with Gallocyanin chrom-alumstain and Golgicox method. Ultrastructural study with the aid of the transmission electron microscope was done for the adult and aged rats. The results of this study revealed that the mammillary body is composed of a lateral and a medial mammillary nucleus, the latter has been subdivided into four subnuclei: pars lateralis, pars medianus, pars medialis, and pars posterior. The cells are either medium-sized or small and the sizes differ, among different subnuclei. The largest cell sizes are found in the lateral mammillary nucleus. These cells have long branching dendrites that are often beaded with no spines. Most cells in the medial mammillary nucleus are characterized by long branching dendrites and exhibit numerous spines. Cells of the mammillary nuclei are characterized by closely apposed neuronal somata and imaginations of the nuclear membrane. There are also various types of axosomatic synaptic terminals with the mammilary neurons. The neurons of the mammillary nuclei showed increase in the amount of Nissl material, progressive increase in thickness, extension and branching of their dendrites with development, there is also apparent increase in the size of the mammillary body. In the aged rat, there are some degenerative changes in the mammillary neurons in the form of apparent reduction in the size of the mammillary body relative to the adult age. There is decreased staining affinity of the cytoplasm, extensive decrease in the thickness and extension of the dendrites with decrease in the amount of somatic and dendritic spines. Most neurons reveal progressive accumulation of lipofuscin pigment and marked imaginations of the nuclear membrane with the progress of age. As the mammillary body is involved mainly in memory, this function could be expected to decline with age as a consequence of these degenerative changes

study on postnatal development and ageing changes of red nucleus in the albino rat

The red nucleus is one of the most important structures in the midbrain tegmentum. It plays an important role in the control of motor activities. The aim of the present work is to demonstrate the structure of the red nucleus and the characteristics of its constituent neurons during the various stages of postnatal development, it also includes the study of the ageing effect on the features of its cells. In this work, a total number of 40 albino rats was used. The following postnatal age groups of animals were studied; newly born, seven days, fifteen days and three months old [adult rats] in addition to the aged group of animals [two years old rats]. Animals were sacrificed and the midbrain region was dissected. In each age group, three midbrain specimens were processed to be studied by Einarson's Gallocyanin stain and another three specimens were processed to be studied by Golgicox method. The ultrastructural study for the cells of the red nucleus was done by transmission electron microscope. By using Gallocyanin stain, the red nucleus appeared as a circumscribed mass of cells. The caudal magnocellular part was composed mainly of large neurons and few medium and small sized neurons. The rostral parvocellular part consisted mainly of medium and small sized neurons. The cellular content of Nissl granules increased gradually from the newly born age up to the adult stage. In the aged group of animals, the cells of the red nucleus appeared to be lightly stained as compared to the adult animals indicating loss of Nissl granules. Golgi stain revealed that the caudal magnocellular part of the red nucleus was formed of different types of cells [multipolar, pyramidal and fusiform cells]. Their nerve processes showed gradual increase in the length and branching with the progress of age up to the adult stage. In the aged group of animals, these neurons showed a decrease in the extension of the nerve processes as compared to the adult group. The ultrastructural study of the caudal magnocellular part of the red nucleus in the adult animals revealed that the large neurons were characterized by the presence of rounded nucleus while the medium sized neurons had an invaginated nucleus. The cytoplasm of these cells was rich with ribosomes, rough endoplasmic reticulum and mitochondria. Several types of axosomatic synaptic terminals appeared to be present. In the aged animals, the ultrastructural study of these cells showed marked decrease in the amount of ribosomes and rough endoplasmic reticulum as compared to the adult animals. There was also accumulation of lipofuscin granules in their cytoplasm. It was concluded from this study that during the development of the red nucleus, its constituent neurons showed a progressive increase in their content of Nissil granules from the newly born age up to the adult stage. Their nerve processes also showed increase in the extension and branching. The wide variety of synaptic terminals with rubral neurons indicated the presence of several sources involved in the integration of descending motor information. In the aged animals, the rubral neurons showed several degenerative changes that could lead to impairment of motor activities