الفهرس 
ACKNOWLEDGMENT
Organization of the Spinal Cord in albino ratOnly 14 pages are availabe for public view
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Abstract
The spinal cord is part of the central nervous system (CNS) which is protected by the bony structures of the vertebral column. The spinal cord is divided into four parts: cervical, thoracic, lumbar and sacrococcygeal. The transverse section of the lumbar segment of the spinal cord is formed of two symmetrical portions which are separated anteriorlly by anterior median fissure, posteriorlly by posterior median septum and are connected by the transverse anterior and posterior commissures. On both sides of the cord there are the anterior lateral and posterior lateral fissures where the ventral and dorsal rootlets emerge from the cord to form the spinal nerves. The spinal cord is formed of gray matter which is surrounded by the white matter at its circumference. The white matter is divided into the dorsal, dorsolateral, lateral, ventral and ventrolateral funiculi and consists of a mixture of nerve fibers, neuroglia, and blood vessels. The gray matter is divided into the dorsal horn, lateral horn, ventral horn and acentro-medial region surrounding the central canal (central gray matter). The gray matter has multipolar neurons, neuroglia and blood vessels. The dorsal root ganglion is formed of pseudo-unipolar neurons.
Alloxan (2, 4, 5, 6 tetraoxypryimidine; 5, 6 dioxyuracil) is a diabetogenic agent. The cytotoxic action of this agent is mediated by reactive oxygen species. The action of the reactive oxygen species with a simultaneous massive increase in cytosolic calcium concentration cause rapid destruction of B cells of the pancrease.
The aim of the present work is to demonstrate the effect of maternally – induced diabetes mellitus on the development of the gray matter of the lumbar segments of the spinal cord and the corresponding dorsal root ganglia.
A total number of forty adult female Sprague Dawley albino rats were used in this work. They were divided into two equal groups, group I (control group) and group II (an experimental group). The female albino rats in the experimental group were given alloxan monohydrate 150 mg /kg body weight (dissolved in one ml saline) intraperitoneally. The female rats were given 20% glucose solution orally instead of drinking water after 6 hours of alloxan injection .For the next 24 hours; the female rats were kept on 5 % glucose solution orally to prevent hypoglycemia. After one week blood glucose level was determined using glucometer and rats having level above 200 mg/dl were considered diabetic. The ages studied in this research were embryos of gestational day 15 and 18, newborns, 10 days and 20 days old.
In this work, several histological techniques were used. Gallocyanin chrom-alum staining method was used to demonstrate the neuronal structure of the developing spinal cord and the effect of maternally –induced diabetes mellitus on its cellular development. Electron microscopic study was also done to demonstrate the effect of maternally –induced diabetes mellitus on the ultra-structure of the cells of the gray matter of the spinal cord and the dorsal root ganglia. In addition the numbers of the cells of the ventral, dorsal and lateral horns of the gray matter and the numbers of the cells of the lumbar dorsal root ganglion were counted in all studied groups using image analysis system (image j program) and statistically analyzed.
The results of this study revealed that the spinal cord was formed of central H-shaped gray matter surrounded by peripheral white matter. The gray matter had ventral, dorsal horns and in some segments there were lateral horns. This shape of the gray matter appeared at the 15th day prenatally and became well organized at the newborn age. The ventral, dorsal and lateral horns of the gray matter were characterized by the presence of variable sized multipolar nerve cells with pale or vesicular and round nuclei and their cytoplasm contained a large amount of Nissl substance and neuroglial cells. The morphology of the multipolar nerve cells appeared from the 15th day prenatally and reached to the adult appearance at the age of 20th day postnatally with marked reduction in the packing density and more precise demarcation between the multipolar neurons and the neuroglial cells. By electron microscopic method, the multipolar neurons of the gray matter of the spinal cord is characterized by ovoid nuclei with indented nuclear membrane in the ventral and lateral horns and smooth nuclear membrane in the dorsal horn. The cytoplasm of these neurons contained the usual cytoplasmic organelles.
The dorsal root ganglion is characterized by the presence of large diameter cells with light stained cytoplasm, round to ovoid cell membrane and round paracentral nuclei and small diameter cells with darkly stained cytoplasm, angular cell membrane, and central round nuclei and usually arranged in groups .The cytoplasm of both cells displays fine granularity which more concentrated in the perinuclear area. The cell membrane of the large and small cells is surrounded by the satellite cells which are darkly stained small flat cells. By electron microscopic method, the large diameter cells are characterized by round nuclei surrounded by cytoplasm which contains mitochondria of variable shape, rough endoplasmic reticulum and a lot of ribosomes.
In this work, the embryos and pups of the diabetic mothers showed the manifestation of nerve cell degeneration of the gray matter of the spinal cord and the dorsal root ganglion at the 15th day prenatally. The cells were less crowded with multiple intercellular spaces. The degenerative changes are in form of eccentric darkly stained nuclei with multiple intercellular vaculation observed in the gray matter of the spinal cord . Vaculation of the cytoplasm of the large diameter cells and dark staining of some small diameter cells with multiple intercellular spaces are presented in the dorsal root ganglion at the 18th day prenatally. These degenerative changes became more marked in the new born where the gray matter showed numerous cells with darkly stained nuclei and some cells had eccentric pyknotic nuclei with pale vacuolated cytoplasm. This effect was confirmed by the electron microscopic examination that revealed peripheral chromatin condensation, dilated rough endoplasmic reticulum, damaged mitochondria and disrupted organelles.
In addition, the cells of the dorsal root ganglion revealed disappearance of the nucleoli of many large cells, intercellular vaculation. These changes of the dorsal root ganglionic cells were confirmed by electron microscopic examination that revealed increase the density of the chromatin with focal clumping, vacuolated mitochondria and marked intercellular vaculation.
At the 10th day and 20th day postnatally, the degenerative changes of the neurons of the gray matter of the spinal cord and the cells of the dorsal root ganglion were less extensive than the newborn age.
Measuring the number of the cells of the dorsal root ganglion and the nerve cells of the ventral, lateral and dorsal horns of the gray matter of the spinal cord of embryos and pups of diabetic mothers per area showed highly significant decrease as compared with the control.
It was obvious from the results of this study that the maternal diabetes exerts a profound and detrimental effect on the structure of the gray matter of the spinal cord and the corresponding dorsal root ganglia of the developing feotus/pup.
Feotal sensory and motor defects that are associated with maternal diabetes are appalling. Thus, early management of maternal diabetes, whether before, during or after pregnancy, is essential for proper health of the mother and feotus.