Anat Cell Biol.  2012 Sep;45(3):178-184. 10.5115/acb.2012.45.3.178.

Effects of high-fat diet on the numerical density and number of neuronal cells and the volume of the mouse hypothalamus: a stereological study

• Namavar MR
• Raminfard
• Jahromi ZV
• Azari H

• KMID: 2046745
• DOI: http://doi.org/10.5115/acb.2012.45.3.178

Abstract

It has been demonstrated that the type of diet affects the brain structure and function. Consumption of fat-rich food is one of the most important factors that lead to increase in the prevalence of cardiovascular and neurological diseases. High-fat diet may change the volume and neuronal number or density in the hypothalamus, which is the center of energy control. Therefore, this study was designed to study the effect of high-fat diet on the density and number of neurons, and also the volume of hypothalamus in adult male mice. Forty male mice were divided into the control and experimental groups. The control group were fed with standard and the experimental groups, with high-fat diet for 4 (short-term) or 8 (long-term) weeks. The animals were perfused and brains were immediately removed, post-fixed and cut coronally and serially using cryostat at 30-microm thickness. Every 6th sections were stained by cresyl violet. The numerical density and number of neuron and the volume of hypothalamus were estimated by using unbiased stereological methods. Data analysis showed that both short and long time consumption of high-fat diet decreased the neuronal cell density of the hypothalamus. Interestingly, despite a decrease in the neuronal cell density, long time consumption of high-fat diet could significantly increase the volume of hypothalamus (P<0.05). High fat diet decreased the neuronal cell density and increased the volume of the hypothalamus, but it did not significantly change its total neurons. These changes might be due to an increase in the extracellular space through inflammation or gliosis in the hypothalamus.

Keyword

High-fat diet; Hypothalamus; Obesity; Stereology

MeSH Terms

Adult
Animals
Benzoxazines
Brain
Cell Count
Diet
Diet, High-Fat
Extracellular Space
Gliosis
Humans
Hypothalamus
Inflammation
Male
Mice
Neurons
Obesity
Prevalence
Statistics as Topic
Viola
Benzoxazines

Figure

• 

  Fig. 1 Mean value±SEM of volume of the total hypothalamus in mice were fed with normal and high fat diet (HFD) for short and long-term (mm3). Group: 1, short-term control; 2, long-term control; 3, short-term HFD; 4, long-term HFD. *Significant difference with short-term control group (P<0.05). †Significant difference with long-term control group (P<0.05). ‡Significant difference with short-term HFD group (P<0.05).

• 

  Fig. 2 Mean value±SEM of numerical density of neuron (neuron/mm3) in total hypothalamus of mice were fed with normal and high fat diet (HFD) for short and long-term. Group: 1, short-term control; 2, long-term control; 3, short-term HFD; 4, long-term HFD. *Significant difference with short-term control group (P<0.005). †Significant difference with long-term control group (P<0.001).

• 

  Fig. 3 Mean value±SEM of total number of neurons of the total hypothalamus in mice were fed with normal and high fat diet (HFD) for short and long-term. Group: 1, short-term control; 2, long-term control; 3, short-term HFD; 4, long-term HFD.

• 

  Fig. 4 Cresyl violet staining of hypothalamus in normal (A-D) and high-fat (E-H) diet treated mice. An increase in extracellualr space is evident in the hypothalamus of high-fat diet treated mouse (E-H, arrows). This figure represents the plate 49 in the mouse brain in stereotaxic coordinates [20]. 3v, third ventricle; Arc, arcuate hypothalamic nucleus; dmh, dorsomedial hypothalamic nucleus; fr, fasciculus retroflexus; fx, fornix; me, median eminence; mt, mammillothalamic tract; vmh, ventromedial hypothalamic nucleus. Scale bars=400 µm (A, E), 200 µm (B, F), 100 µm (C, D, G, H).

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