الفهرس 
Literature ReviewOnly 14 pages are availabe for public view
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Abstract
Caloric sweetener sucrose is an essential component of modern diet. However, sucrose diet has an adverse effect on body weight and is associated with medical complications. So, substituting sucrose with low calorie sweeteners either synthetic as aspartame or natural as stevia is an effecticious weight management strategy. In addition to its neuroprotective action.
The present study is an investigation to compare aspartame and stevia as an artificial and natural non calorie sweeteners and sucrose as a high calorie widely used sweetener.
To achieve this object, a total number of 64 male albino rats were currently investigated. Animals were classified into four groups. The first group served as control group, the second group represented the sucrose group, the third group represented the aspartame and the fourth represented the stevia group. Eight animals from each group were dissected after 30 days and 90 days.
Morphological Investigation:
Stevia group or aspartame group administration for 90 days caused a significant decrease in final body weights and body weight gain of rats. On the contrary sucrose administrated animals signified a percentage of increase in final body weights and body weight gain when compared to control ones.
Aspartame group or stevia group treated animals clarified a reduction in food consumption /rat/day. Calculated caloric intake elucidated a noticeable decrease in the mean values of aspartame and stevia supplemented animals compared to sucrose and control groups.
Biochemical Investigations:
Sucrose group and aspartame group administration to rats for 30 and 90 days recorded a significant decrease in hippocampus total antioxidant activity compared to control rats. The percentage of reduction in sucrose and aspartame were 46.54% and 81.13% respectively. On the other hand, stevia administration didn’t show a significant variation in hippocampus total antioxidant activity compared to control group.
Marked increase was recorded in hippocampus malondialdehyde (MDA) in sucrose or aspartame treated rats after 30 days of experimental period compared to control group. At the end of the study period sucrose and aspartame groups demonstrated a significant increase of MDA levels. While stevia treated rats elucidated non-significant changes in hippocampus MDA level compared to control ones. The percentage of elevation in sucrose and aspartame groups were 10.86% and 36.95% respectively compared to control group.
Significant decrease in hippocampus catalase activity (CAT) was manifested in aspartame group and sucrose group compared to control group. Stevia supplementation rats did not show variation in hippocampus CAT compared to control group.
Sucrose and aspartame treatments to experimental rats for 90 days revealed a significant decrease in the mean values of hippocampus glutathione activity (GSH) compared to control animals. On the other hand, stevia treated animals did not record any significant changes during the study period compared to control.
Hippocampus nitric oxide activity (NO) in rats treated with sucrose and aspartame group for 30 and 90 days showed significant augmenation compared to their control. Whereas, non-significant change in the mean of hippocampus NO in stevia treated rats during the period study from control group was recorded.
A significant decrease in hippocampus Na+-K+ ATPase was recorded through the period study in aspartame treated rats. The percentage of reduction in this group was (37.78% and 45.72%) after 30 and 90 days respectively compared to control group. A slight decrease in the mean values of hippocampus Na+-K+ ATPase was denoted in rat’s administrating sucrose during this study period. Quite the reverse, stevia administration to rats didn’t cause any significant variation in hippocampus Na+-K+ ATPase compared to control ones.
A significant decrease in the mean values of hippocampus total protein was indicated in rats administrated sucrose or aspartame for 90 days. The percentages of reduction were (36.19% and 69.48%) in sucrose or aspartame groups respectively compared to control group. On the contrary, stevia administration to rats recorded a slight increase in hippocampus total protein compared to control ones.
After 90 days of study period, significant increase (p<0.001) in hippocampus GGT level was denoted in aspartame group compared to control group. On the contrary, no significant variations occurred in hippocampus GGT level in rats that were administrated either sucrose or stevia during period of study in relation to control rats.
Either sucrose or aspartame groups treatment to experimental rats for 90 days demonstrated a significant decrease in the mean values of serum creatine kinase brain type (CK-BB) compared to control animals. On the other hand, rats treated with stevia did not show any significant change in serum CK-BB level for the whole period of study from control rats.
Histological, Histochemical and Immuno-histochemical Investigation:
Hippocampus of rats after 30 days of sucrose treatment manifested neuronal degeneration in dentate gyrus with pyknotic nuclei and fewer pyknotic pyramidal cells. Again after 90 days of sucrose supplementation to animals, degeneration, necrosis in pyramidal layer and vacuolation in glial cells were manifested. Dilatation and congestion in some blood vessels were also a prominent feature.
Hippocampus sections from rats treated with aspartame after 30 days showed dilatation and congestion of blood vessels with inflammatory infiltrative cells. Moreover, less number of pyramidal cells in CA3 layer and pyknotic nucleus associated vacuolation of the glial cells in molecular layer were observed. Neuronal degeneration in dentate gyrus with congestion in blood vessels, haemorrhage and spongiform (micro vacuolated) changes in the neuropil were also found. Whereas, after 90 days in rats of aspartame treatment, hippocampus sections showed degeneration in neural cells with lesser dispersed chromatin material that was clumped to the inner side of nuclear membrane and other shrunken neurons with pyknotic nuclei. Moreover, dilatation, congestion of blood vessels with inflammatory infiltrative cells and condensation of chromatin material in neurons, swollen and degeneration in the neuropil were manifestated. Also, degeneration, necrotic granular cells and vacuolated molecular layer, condensation of the granular layer and pyknotic nuclei were observed in pyramidal neurons and diffused gliosis in the neuropil were also found.
Rats administrating stevia for 30 and 90 days manifested few number of pyramidal cells that were shrunken with condensed and deeply stained nuclear chromatin, neuronal degeneration with hemorrhages. Also, mild congestion in blood vessels with perivascular edema and near to normal molecular layer was shown. Nevertheless, slight damage was observed as designated by swollen and degenerated neurons in the neuropil. On the other hand, most areas showed near to normal pattern of the granular and the neuropil areas.
Histochemically, hippocampus sections realized significant decrease of total protein contents in sucrose and aspartame groups within 30 and 90 days. On the other hand, non-significant alteration in total protein contents in hippocampus tissue sections of rats treated with stevia either at 30 or 90 days were denoted.
Also, hippocampus sections stained with Congo red from rats treated with sucrose or aspartame manifested cellular homogenous pink deposits of amyloid throughout the hippocampus tissue during the study period. While, stevia group manifested limited or few amyloid depositions compared to control animals.
The Bax protein (Bcl-2 associated X protein) expression and activated Caspase 3 were shown as brown coloured neuronal cells that were considered as positive cells. Both immune histochemical stains significantly increased in the hippocampus sections of rats administrating sucrose or aspartame for 90 days as compared to the control group. On the other hand, hippocampus sections from rats treated with stevia showed non-significant alterations in these stains.
In conclusion, stevia, a non-calorific sweetener, is a better alternative to the synthetic sweetener aspartame in relation to the results of this study. Stevia is useful in improving the oxidative stress biomarkers of brain.