الفهرس 
CONTENTSOnly 14 pages are availabe for public view
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Abstract
Palm oil is one of the widespread vegetable oils as it is widely used in cooking and frying purposes because it contains saturated and unsaturated fatty acids in certain proportions that make it thermally stable. Because of the economic situation, people heat palm oil more than once at homes and restaurants to reduce the financial costs. Previous researches were interested in studying the physical and chemical changes in the composition of repeatedly heated palm oil. As a result of heating, harmful compounds are formed and when used in food carry risk factors to body organs, tissues and systems. Chemicals such as aldehydes, acrylamides, alcohols and activated oxygen radicles are released and are proven to be hazardous to body organs. Also, previous research works have found that rats fed with food containing recycled palm oil for long periods suffer from pathological changes in tissues of some internal organs. However there are a lot of controversial findings as regard the hazardous effects of heating and repeated heating of palm oil. The possibility of recovery of damaged tissues exposed to feeding by palm oil in its different and heated forms has not been investigated before. The current research work is conducted in order to investigate the precise changes in vital organs of rats fed fresh, once heated, and five times heated palm oil for 8 weeks. These organs are the liver, kidney, heart, aorta, testis and cerebellum. The study includes light microscopy, using stains such as hematoxylin and eosin, Masson trichrome for collagen fibers, and orcein for elastic fibers. Electron microscopic investigations are performed to show detailed changes in the structure of the targeted vital organs. Morphometric measurements are applied which include cellular number per area, cellular diameter, layer thickness, diameters of tubes, areas of tissues and ratios of layers. Morphometric data are statistically analyzed and used to confirm histological findings. Potentials of recovery are studied by stoppage giving the heated palm oil for 4 weeks. We conducted the study on fifty adult white male albino rats whose weight ranged between approximately 180-200 grams, and they were divided into 5 equal groups; C, F, H1, H5, R groups: The first group, the control, (C group): rats received balanced meals and water for eight weeks. The second group, fresh oil, (F group): rats received meals containing 15% fresh unheated palm oil for 8 weeks. The third group once heated oil, (H1 group): rats received meals, 15% of which contained once heated palm oil for a period of 8 weeks. The fourth group, five times heated oil (H5 group): rats that were fed meals, 15% of which contained heated palm oil five times for 8 weeks. The fifth group, recovery group (R group): rats that received meals, 15% of which contained heated palm oil five times for eight weeks, then left after eating balanced meals and water for additional four weeks. Body weights were measured and recorded weekly for all groups. The rats of the first four groups were sacrificed after eight weeks, the rats of the fifth group after twelve weeks. The vital organs were dissected and extracted for examinations. The right lobe of the liver, the right kidney, the right ventricle, the proximal part of thoracic aorta, the right testis and the anterior lobe of the right cerebellar hemisphere were processed for light microscopy and were stained by hematoxylin and eosin for cellular and tissue components, Masson trichrome for evaluation of collagen fibers and orcein stain for detection of elastic fibers of the aorta (middle segment of thoracic aorta). The left lobe of the liver, the left kidney, the left ventricle, the distal segment of thoracic aorta, the left testis and the anterior lobe of the left cerebellar hemisphere were processed for electron microscopic study. The commonly occurring findings are pictured and recorded. BODY WEIGHT Body weight was significantly increasing especially in the H5 group. However recovery group showed significant decrease in body weight. LIVER- Fatty droplets and simple mononuclear cellular infiltration were observed with slight dilation in the central vein and blood sinusoid in F and H1 groups. In H1 group, hydropic degeneration and fatty droplets as well as mononuclear cellular infiltration were observed. In H5 group there were excessive fatty droplets in hepatocytes, vascular dilation and congestion, and signs of degeneration of some liver cells. In this H5 group excessive deposition of collagen fibers is an indicator of start liver fibrosis. Ultrastructure features in H5 group included cytoplasmic vaculations and disrupted mitochondria. - In the recovery (R) group, these changes showed substantial ameliorations indicating possibility of recovery of the liver after stoppage of administration of heated palm oil. KIDNEY- A simple mononuclear cellular infiltration in the renal tubes was observed in group F. H1 group presented widening of Bowman’s space, mononuclear cellular infiltration and vascular congestion and small areas of hemorrhage. In H5 group there were shrunken distorted glomeruli, pyknotic nuclei of the cells lining of some renal tubules, multiple areas of hemorrhage, and multiple hyaline casts. In H5 group it was also observed that there was fusion of foot processes of podocytes, loss of microvilli and basal infoldings of renal tubular epithelium with excessive deposition of collagen fibers. - The recovery group showed partial improvement of the degenerative features and fibrosis of the kidney. HEART- A simple mononuclear cellular infiltration was observed and slight congestion in the capillaries in the longitudinal and transverse sectors in the group F. In group H1, the presence of fragmentation (laceration) and disorientation of cardiomyocyte was obse rved. There is small areas of hemorrhages and increase of intercellular spacing. Moreover, in H5 group an increase in fragmentation and disorientation of multiple cardiomyocytes and increase of mononuclear cellular infiltration and multiple areas of hemorrhages were observed. In addition, deeply stained homogenous cardiomyocytes with absent or pyknotic nuclei and the increase of intercellular spaces. - After stoppage of consuming reheated palm oil, an improvement in the previous pathological changes was observed in the recovery group (R), but it did not return to its normal nature. AORTA- In F group, irregularity in the intima was seen. The elastic fibers in the middle layer appeared straight and lose their natural undulation. In H1 group there were sloughing and separation of the endothelial cells as well as focal thickening in intima, focal discontinuity in the inner elastic lamina and the presence of cytoplasmic vaculation in some smooth muscle cells of the media. In H5 group, there were thickening in the wall of the aorta and disorganization in tunica media which contained vacuolated smooth muscle cells. Disarrayed fragmented elastic fibers in tunica media were noticed. Other elastic fibers disappeared and were replaced by a network of fine fibrils. - After stoppage of consuming reheated palm oil, an improvement in the previous pathological changes was observed in the fifth group when compared to the fourth group, but it did not return to its normal picture. By using the light microscope (orcein stain): - In the second group, a local irregularity was observed in the inner elastic lamina. - Discontinuity in the inner elastic lamina and thinning in the outer elastic lamina and fragmented some elastic fibers in tunica media of the third group. - Upon stopping the consumption of reheated palm oil, an improvement was observed in the previous pathological changes in the elastic fibers but they did not reach the normal state. TESTIS- In F group, there was irregularity of some seminal tubules, wide interstitium, widening of intercellular spaces, vaculation in the germinal epithelium and separation of spermatogenic cells from the basal membrane. In H1 group there were distorted seminiferous tubules, edema of interstitial tissue, increased vaculation of germinal epithelium and increased intercellular spaces. In H5 group there were small sized seminiferous tubules, congestion of blood vessels, degeneration of spermatogenic cells, decreased thickness of the germinal epithelium and marked decrease in the number of sperms. In H5 group there was increase in deposition of collagen fibers. By using the light microscope (masson trichrome stain): - The deposition of collagen fibers was observed in a simple degree in the second group, in a medium degree in the third group and in marked degree in the fourth group around the seminal tubules, blood vessels and spermatogenic cells. - In R group, after stopping the consumption of the reheated palm oil, an improvement in the previous pathological changes in the structure and layers of the seminiferous tubules was observed, also decrease in deposition of collagen fibers was noticed, but it did not return to its first condition. CEREBELLUM - In F group, there were vaculations between Purkinje and granular layers with few darkly stained Purkinje cells. - In H1 group, there were increased numbers of darkly stained Purkinje cells surrounded by empty neuropil. - In H5 group, there was decreased thickness of the granular layer, aggregated darkly stained granular cells with areas of patchy loss, increase number of displaced dark shrunk Purkinge cells surrounded by empty neuropil. There were also focal areas of neuron loss. - When the reheated palm oil was stopped, partial improvement in the pathological changes in the cerebellum was observed but it did not reach the normal state.