The impact of consuming different types of high-caloric fat diet on the metabolic status, liver, and aortic integrity in rats

Abstract

Consumption of high-caloric diets contributes to the alarming number of overweight and obese individuals worldwide, which in turn leads to several diseases and multiple organ dysfunction. Not only has the number of calories taken per day but also the type of fat in the diet has an important impact on health. Accordingly, the purpose of the current study was to examine the impact of different types of high-caloric fat diets on the metabolic status and the integrity of the liver and aorta in albino rats. Adult male albino rats were divided into 6 groups: Control group, long chain-saturated fat group (SFD), long chain-monounsaturated fat (MUFAs) group, long chain-polyunsaturated fat (PUFAs) group, medium-chain fat (MCFAs) group, and short-chain fat (SCFAs) group. Body mass index (BMI), Lee index, and visceral fat amount were reported. Serum levels of insulin, liver transaminases, lipid profile, and different oxidative stress and inflammatory markers were evaluated. Homeostasis Model Assessment of Insulin Resistance (HOMA-IR), and adiponectin/leptin ratio were also calculated. Histopathological examinations of liver and aorta with Masson's trichrome stain, and immune-staining for Nuclear Factor Erythroid-2-Related Factor-2 (Nrf2) were also done. SFD group showed significantly elevated liver transaminases, inflammatory markers, HOMA-IR, dyslipidemia, reduced adiponectin, and deficient anti-oxidative response compared to other groups together with disturbed hepatic and aortic architecture. Other treated groups showed an improvement. PUFAs group showed the highest level of improvement. Not all high-fat diets are hazardous. Diets rich in PUFAs, MUFAs, MCFAs, or SCFAs may protect against the hazards of high caloric diet.

Keywords: High caloric fat diet; Insulin resistance; Leptin; MCFAs; MUFAs; PUFAs; SCFAs.

Figure 1

Hematoxylin and eosin-stained liver sections in the different groups: (A) Control group, normal liver structure with central vein (circle) and hepatocytes (arrow) (×200). (B) Long chain saturated fat diet group, the liver shows diffuse injury with necrosis (arrow) and congestion (asterisk) (×200). (C) Long chain monounsaturated fat diet group, the liver shows focal mild lymphocytic infiltrate (arrow) (×200). (D) Long chain polyunsaturated fat diet group, the liver structure was normal regarding hepatocytes and bile canaliculi (×200). (E) Medium chain fat diet group, the liver shows bile duct proliferation (asterisks) and focal mild lymphocytic infiltrate (arrowhead) (×200). F) Short chain fat diet group, the liver shows focal mild lymphocytic infiltrate (arrow) (×200).

Figure 2

Masson’s trichrome-stained liver sections in the different groups: (A) Control group, normal liver structure with central vein (circle) and hepatocytes (arrow) (×200). (B) Long chain saturated fat diet group, the liver shows diffuse injury with necrosis (arrow) and congestion (asterisk) (×200). (C) Long chain monounsaturated fat diet group, the liver shows focal mild lymphocytic infiltrate (arrow) (×200). (D) Long chain polyunsaturated fat diet group, the liver structure was normal regarding hepatocytes and bile canaliculi (×200). (E) Medium chain fat diet group, the liver shows fibrous tissue band (asterisk) and focal mild lymphocytic infiltrate (arrowhead) (×200). (F) Short chain fat diet group, the liver shows focal mild lymphocytic infiltrate (arrow) (×200).

Figure 3

Immuno-expression of Nrf2 in liver sections in the different groups: (A) Control group, marked cytoplasmic expression in hepatocytes (×400). (B) Long chain saturated fat diet group, the liver shows moderate cytoplasmic expression in hepatocytes (×400). (C) Long chain monounsaturated fat diet group, the liver shows mild cytoplasmic and moderate nuclear expression in hepatocytes (arrowheads) (×400). (D) Long chain polyunsaturated fat diet group, the liver shows mild cytoplasmic and marked nuclear expression in hepatocytes (×400). (E) Medium chain fat diet group, the liver shows mild nuclear (arrowheads) and cytoplasmic expression in hepatocytes (×400). (F) Short chain fat diet group, the liver shows moderate nuclear expression (arrowheads) and mild cytoplasmic expression in hepatocytes (×400).

Figure 4

Hematoxylin and eosin-stained aorta sections in the different groups: (A) Control group, the aorta showed continuous layer of endothelial at the tunica intima (arrow) and normal thickness of the tunica media (asterisk) and adventitia (arrowhead) (×400). (B) Long chain saturated fat diet group, the aorta shows marked tunica media thickening (asterisk) with congestion (arrows) and lymphocytic infiltration in the adipose tissue around aorta (arrowhead) (×400). (C) Long chain monounsaturated fat diet group, the aorta shows mild intimal and media thickening (×400). (D) Long chain polyunsaturated fat diet group, normal aorta structure (×400). (E) Medium chain fat diet group, the aorta shows moderate intima and media thickening (×400). (F) Short chain fat diet group, normal aorta structure (×400).

Figure 5

Masson’s trichrome-stained aorta sections in the different groups: (A) Control group, normal aorta structure (×400). (B) Long chain saturated fat diet group, the aorta shows marked media thickening and elastosis (arrowhead) (×400). (C) Long chain monounsaturated fat diet group, the aorta shows mild intima and media thickening (asterisk) (×400). (D) Long chain polyunsaturated fat diet group, normal aorta structure (×400). (E) Medium chain fat diet group, the aorta shows moderate media thickening (asterisk) (×400). (F) Short chain fat diet group, normal aorta structure (×400).

Figure 6

Immuno-expression of Nrf2 in aorta sections in the different groups: (A) Control group, the aorta shows marked cytoplasmic expression in muscle layer (×400). (B) Long chain saturated fat diet group, the aorta shows moderate cytoplasmic expression in tunica media (arrow) (×400). (C) Long chain monounsaturated fat diet group, the aorta shows moderate nuclear (arrow) and mild cytoplasmic (arrowhead) expression in tunica media (×400). (D) Long chain polyunsaturated fat diet group, the aorta shows marked nuclear (arrow) and mild cytoplasmic (arrowhead) expression in tunica media (×400). (E) Medium chain fat diet group, the aorta shows mild nuclear (arrows) and cytoplasmic (arrowhead) expression in muscle layer (×400). (F) Short chain fat diet group, the aorta shows moderate nuclear (arrows) and mild cytoplasmic (arrowheads) expression in tunica media (×400).