The effects of different diets (high fat and high fructose diet) on the development of insulin resistance and tissue advanced glycation end product levels in rats

bring many metabolic diseases, especially obesity and diabetes. Recent years, more scientific interest in how can diet effect on brain

function has emerged. We aimed to investigate the effect of high

fructose and high-fat diet on the brain, and whether the presence

of relationship with advanced glycation end products histologically, in rat model.

Materials & Methods: Twenty-four Sprague Dawley rats were

used and divided into 3 groups as control group, high fructose

group and high fatty group. During 12 weeks, while the rats in the

control group were given standard rat chow, those of in the high

fructose and high fatty group were fed with %60 high fructose diet

and %45 high fat diet, respectively. At the end of the experiment,

their brains were removed. AGE and R-AGE expression were evaluated by immunohistochemistry and biochemically.

Results: In the H-E stained sections, the control group rat

brains showed healthy histological appearance. The brain sections

of the high fructose group showed that histological structure was

deteriorated. There was a significant increase in glial cells, especially in the mediobasal hypothalamus. Shrinkage and eosinophilic

staining of the neurons were noticed, chromatin condensation in

the nucleus was prominent. Also, pericellular edema was present

in neurons and glial cells. Similar findings were observed in the

high-fat group. Glial cells were increased compared to the control

group but were less than the high fructose group. There was dilated

blood vessels and pericellular edema. Small eosinophilic neurons

with shrunken nuclei and with condensed chromatin were also

abundantly observed in the high-fat group. In the control group,

no AGE immunostaining was observed in the axonal structures,

whereas immunopositive staining was observed in neural cells.

When the brain sections of high fructose group were examined,

it was observed that AGE immunostaining positivity was more

significant than the control and high-fat group. R-AGE immunostaining intensity in hypothalamus of both high fructose and

high-fat groups was higher than in the control group. Biochemical

results are given in Table 1.

Conclusions: The feeding with both high fructose and highfat diet might cause the deterioration in the brain mainly the hypothalamus, and increased advanced glycation end products may

play an essential role in the development of damage.

Control

Brain

High fructose

Brain

High fat

Brain

Glucose

µmol/L

25,86 25,09 19,42

Insulin

ng/mL

17,93 16,25 17,09

R-AGE pg/mL 93,24 169,42 163,78

GEs ng/mL 132,73 86,85 100,36