الفهرس 
Abstract of the thesisOnly 14 pages are availabe for public view
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Abstract
Metabolic syndrome is becoming more prevalent globally. The combination of high caloric diet intake with decreasing physical activity has been considered to be one of the main contributors to the onset of metabolic syndrome. The quality of individual macronutrients has a more important impact on its progression. The main goal of this work is to compare the influences of various sorts of fat and carbohydrates on the development of metabolic syndrome.
A total of fifty-six adult male albino rats ranging between 130 and 150 grams were utilized in the current experiment. Before the onset of the experiment, they were given a week to get used to the lab environment. During the acclimatization period, they were given a standard diet consisting of commercial rat chow and tap water ad libitum. Mean initial daily food intake and mean initial body mass index were recorded just before the start of the experiment.
Following acclimatization, 8 groups of 7 rats each were assigned at random to receive one of the following feeding regimens for 9 weeks:
1- Control group: This group of rats was provided with a standard commercial rat chow diet consisting of 21% protein, 3% fat, 48% carbs, and 28% additional ingredients such as vitamins, minerals, and fibers. About 3030 Kcal/kg of diet were supplied.
2. Long chain-saturated fat diet group: This group’s rats were supplied with a diet rich in saturated fat. It consists of 40 % fat, mostly butter, 20 % protein, 30 % carbohydrates, and 10 % fiber and vitamins. It offers energy of approximately 5600 Kcal/kg of diet.
3. Long chain-monounsaturated fat diet (MUFAs) group: The rats in this group were provided with a high-fat diet that was primarily composed of olive oil. This diet contains 40 % fat, 20 % protein, 30% carbohydrate, and 10 % fiber and vitamins. It offers energy of roughly 5600 Kcal/kg of diet.
4. Long chain-polyunsaturated fat diet (PUFAs) group: A diet augmented with ω−3 fatty acids was fed to the rats in this group. The ω−3 fatty acid was given by an oral daily dose of 500 mg/kg. It provides about 4940 Kcal/kg of diet.
5. Medium chain fat diet (MCFAs) group: A high-fat diet consisting primarily of palm oil—40% fat, 20% protein, 30% carbohydrates, and 10% fiber and vitamins—was fed to the rats in this group. It supplies roughly 5600 Kcal/kg of diet.
6. Short chain fat diet (SCFAs) group: The rats received a diet enriched with SCFAs. The SCFAs was given by an oral daily dose of 5% wt/wt diet. The combination of SCFAs includes sodium acetate, sodium propionate, and sodium butyrate by the ratio of 12: 5: 3 respectively, it was dissolved in distilled water. It provides about 4880 Kcal/kg diet.
7. Starch group: This group’s rats were fed a diet high in carbohydrates mainly starch. This diet involves 21% proteins, 72.5% carbohydrates mainly from starch, 3% fat and 3.5% fibers and vitamins. Approximately, it offers about 4010 Kcal/kg of diet.
8. Sucrose group: A high-carbohydrate diet rich in sucrose was fed to the rats in this group. It consists of 21% proteins, 72.5% carbohydrates primarily from sucrose, 3% fat, and 3.5% fiber and vitamins. Approximately, it supplies about 4010 Kcal/kg of diet.
During the period of the experiment, food intake, body weight, body mass index (BMI), and blood glucose level were followed up in all groups. Rats were fasted overnight before the day of their decapitation. After that, visceral fat especially retroperitoneal fat was collected and weighed, and collected blood samples were left to clot at room temperature, and then for 15 min, they were centrifuged at 3000 rpm. The serum layer was then removed and placed into prepared Eppendorf tubes. These tubes were then labeled and kept at -20 °C until the following assay was performed:
• For assessment of liver function: “Levels of liver enzymes; aspartate transaminase (AST) and alanine transaminase (ALT) in serum”.
• For assessment of atherogenic index: “Serum lipid profile including total cholesterol (TC), HDL-C, triglycerides (TG), and LDL-C”.
• For assessment of oxidative stress: “Total antioxidants (TA) and Malondialdehyde (MDA)”.
• For assessment of insulin resistance and sensitivity: “Fasting glucose, fasting insulin, HOMA-IR, and HOMA- β”.
• For evaluation of inflammation: “Interleukin-6 (IL-6) and interleukin-10 (IL-10)”.
• For evaluation of adipose tissue dysfunction “Leptin, adiponectin, and Adiponectin/ Leptin ratio”.
The abdomen was dissected, and then the liver, pancreas, kidney, and aorta were removed for histopathological analysis; parts of the rat tissues were used for Hematoxylin and eosin (H&E) staining and Masson’s trichrome staining using standard techniques and other parts were immune-stained for Nrf-2 (Nuclear Factor Erythroid-2-Related Factor 2) measurement.
The results obtained clearly demonstrated that:
• Throughout the whole period of the experiment, food intake in all high fat diet groups significantly decreased, while in high carbohydrate diet groups significantly increased in comparison to the control group. The higher GI carbohydrate; the starch group, showed the significantly highest food intake within the high carbohydrate diet groups.
• Final mean body weight and mean BMI were significantly higher in the high long chain saturated fat diet group, and high carbohydrate diet groups (starch and sucrose) compared to other groups, but there were no significant variations among them.
• After dissection, the weights of retroperitoneal fat were significantly higher in high carbohydrate diet groups (starch, sucrose) and high saturated fat diet group compared to other groups, but there were no significant variations among them.
• The high long chain saturated fat diet group, and high carbohydrate diet groups (starch and sucrose), compared to other groups, showed significantly higher levels of hepatic impairment (indicated by higher ALT, AST), atherogenic index (indicated by deficient HDL-C and elevated TC, TG, and LDL-C), oxidative stress (indicated by higher MDA, and lower TA), inflammation (indicated by higher IL-6, and lower IL-10), insulin resistance (indicated by higher HOMA-IR), and adipose tissue dysfunction (indicated by higher leptin, and lower adiponectin and adiponectin/leptin ratio).
• Within the previous 3 groups, the higher GI carbohydrate, the starch group, showed the worst results.
• MUFAs, PUFAs, MCFAs, and SCFAs diet groups, compared to the previous groups, showed improvements concerning hepatic function (indicated by lower ALT, AST), atherogenic index (indicated by improved HDL-C level, and lower levels of TC, TG, and LDL-C), oxidative stress (indicated by lower MDA, and higher TA), inflammation (indicated by lower IL-6, and higher IL-10), insulin resistance (evidenced by lesser HOMA-IR), and adipose tissue dysfunction (indicated by lower leptin, and higher adiponectin and adiponectin/leptin ratio).
• Within the previous 4 groups, the PUFAs group showed the highest level of improvement, while the MCFAs group showed the lowest level of improvement.
• Microscopic examination of the liver, pancreas, kidney, and aorta revealed that the high GI carbohydrate group showed the worst complications related to these tissues. Groups that received diets rich in MUFAs, PUFAs, MCFAs, or SCFAs showed lower levels of complications related to these tissues. The polyunsaturated fat diet group showed the highest level of improvement and was very close to the normal architecture of tissues.
• Immunohistochemical staining of Nrf-2 showed higher nuclear expression in the groups that received MUFAs, PUFAs, MCFAs, or SCFAs compared to high carbohydrate diets or long chain saturated fat diet groups which showed minimal or no nuclear expression. Marked nuclear expression of Nrf-2 was significantly apparent in the PUFAs group.
In conclusion,
• There are different mechanisms that contribute to the onset of metabolic syndrome. They involve adipose tissue dysfunction, insulin resistance, pancreatic β cell dysfunction, and a state of oxidative inflammatory damage.
• High caloric diet may include high a fat diet or high carbohydrate diet. The type of fat regarding the chain length and saturation of fatty acids may have the most important impact on the initiation and advancement of metabolic syndrome. As well, the glycemic index of the carbohydrate taken in the diet should be considered.
• Regarding the high fat diet, the long chain saturated fatty acid diet has a worse influence on the development of metabolic syndrome and its health hazards than the intake of a diet rich in unsaturated fatty acids, medium chain or short chain fatty acids which are less hazardous and even protective.
• On the other hand, a high carbohydrate diet is even worse than a high saturated fat diet, and high GI carbohydrates, as starch in this study, were proven to be the worst of them all.
Recommendations,
• Selection of the diet macronutrient constituent is a must to live a healthy life.
• High caloric diets rich in saturated fat and high GI carbohydrates should be avoided.
• Substitution of the diet with polyunsaturated and short or medium chain fatty acids positively affects human health and restrains the development of metabolic syndrome and its hazards.
• Caloric intake should balance the daily activity regardless of the source of calories. Excess caloric intake whatever the source alters the functions of vital organs, and produces insulin resistance, oxidative stress, atherogenic lipid profile, and inflammation.
• Further research should be directed to compare the impact of a normal balanced caloric diet with selective types of fat or carbohydrates on health hazard parameters.
• Further research should be directed to compare the impact of the combination of different percentages of macronutrients on the development of metabolic syndrome.
• Further studies should be undertaken by researchers to recommend an effective diet protocol for the treatment of metabolic syndrome.