Limits...
Hard-diet feeding recovers neurogenesis in the subventricular zone and olfactory functions of mice impaired by soft-diet feeding.

Utsugi C, Miyazono S, Osada K, Sasajima H, Noguchi T, Matsuda M, Kashiwayanagi M - PLoS ONE (2014)

Bottom Line: Recent studies have shown that a reduction of mastication impairs both neurogenesis in the hippocampus and brain functions.Avoidance of butyric acid was reduced by the soft-diet feeding.The present results suggest that feeding with a hard diet improves neurogenesis in the SVZ, which in turn enhances olfactory function at the OB.

View Article: PubMed Central - PubMed

Affiliation: Department of Oral and Maxillofacial Surgery, Asahikawa Medical University, Asahikawa, Japan; Department of Sensory Physiology, Asahikawa Medical University, Asahikawa, Japan.

ABSTRACT
The subventricular zone (SVZ) generates an immense number of neurons even during adulthood. These neurons migrate to the olfactory bulb (OB) and differentiate into granule cells and periglomerular cells. The information broadcast by general odorants is received by the olfactory sensory neurons and transmitted to the OB. Recent studies have shown that a reduction of mastication impairs both neurogenesis in the hippocampus and brain functions. To examine these effects, we first measured the difference in Fos-immunoreactivity (Fos-ir) at the principal sensory trigeminal nucleus (Pr5), which receives intraoral touch information via the trigeminal nerve, when female adult mice ingested a hard or soft diet to explore whether soft-diet feeding could mimic impaired mastication. Ingestion of a hard diet induced greater expression of Fos-ir cells at the Pr5 than did a soft diet or no diet. Bromodeoxyuridine-immunoreactive (BrdU-ir) structures in sagittal sections of the SVZ and in the OB of mice fed a soft or hard diet were studied to explore the effects of changes in mastication on newly generated neurons. After 1 month, the density of BrdU-ir cells in the SVZ and OB was lower in the soft-diet-fed mice than in the hard-diet-fed mice. The odor preferences of individual female mice to butyric acid were tested in a Y-maze apparatus. Avoidance of butyric acid was reduced by the soft-diet feeding. We then explored the effects of the hard-diet feeding on olfactory functions and neurogenesis in the SVZ of mice impaired by soft-diet feeding. At 3 months of hard-diet feeding, avoidance of butyric acid was reversed and responses to odors and neurogenesis were recovered in the SVZ. The present results suggest that feeding with a hard diet improves neurogenesis in the SVZ, which in turn enhances olfactory function at the OB.

Show MeSH

Related in: MedlinePlus

Fos-ir cells after exposure to urinary odor in the OB and Pir.Sagittal sections of the OB and Pir after exposure of mice fed only a hard diet (A and E), only a soft diet (B and F), or a hard diet for 3 months after a soft diet for 1 month (C and G) to urinary odor, respectively. Scale bar: 200 µm (C), 500 µm (G). D: The numbers of Fos-ir cells in the mitral cell layer in 500 µm thickness from Figure 108 of the mouse atlas (lateral 0.84 mm) of the OB to the lateral side of mice fed only the hard diet (black column; n = 5), only the soft diet (white column; n = 5), or the hard diet after the soft diet (gray column; n = 5). H: The number of Fos-ir cells in 400 µm thickness from Figure 114 of the mouse atlas (lateral 1.56 mm) of the Pir of mice fed only the hard diet (black column; n = 5), only the soft diet (white column; n = 5), or the hard diet after the soft diet (gray column; n = 5). *: p<0.05; **: p<0.005.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4016307&req=5

pone-0097309-g003: Fos-ir cells after exposure to urinary odor in the OB and Pir.Sagittal sections of the OB and Pir after exposure of mice fed only a hard diet (A and E), only a soft diet (B and F), or a hard diet for 3 months after a soft diet for 1 month (C and G) to urinary odor, respectively. Scale bar: 200 µm (C), 500 µm (G). D: The numbers of Fos-ir cells in the mitral cell layer in 500 µm thickness from Figure 108 of the mouse atlas (lateral 0.84 mm) of the OB to the lateral side of mice fed only the hard diet (black column; n = 5), only the soft diet (white column; n = 5), or the hard diet after the soft diet (gray column; n = 5). H: The number of Fos-ir cells in 400 µm thickness from Figure 114 of the mouse atlas (lateral 1.56 mm) of the Pir of mice fed only the hard diet (black column; n = 5), only the soft diet (white column; n = 5), or the hard diet after the soft diet (gray column; n = 5). *: p<0.05; **: p<0.005.

Mentions: Next, we explored the effect of hard-diet feeding for 3 months on responses to odors at the OB and piriform cortex (Pir) of mice fed a soft diet for 1 month. Exposure to urinary odor excreted by males induced Fos-immunoreactivity (Fos-ir), which is correlated with cellular activity, in various cells of the OB of mice fed the hard diet (Figure 3A). In contrast, Fos-immunoreactivity at the OB of mice fed the soft diet was low (Figure 3B). In mice fed the hard diet for 3 months after the soft diet for 1 month, exposure to the urinary odor induced levels of Fos-ir cells at the OB that were similar to the levels in mice fed only the hard diet (Figure 3C). Figure 3D shows the number of Fos-ir cells at the mitral cell layer of the OB after exposure to urinary odor. The data from each group were cast into a one-factor ANOVA as follows: hard, soft, or hard after soft diet. One factor ANOVA revealed the main effect of diet (F(2, 12) = 4.78, p<0.05). Fisher's PLSD post-hoc testing indicated that the mitral cell layer of the OB in mice fed the hard diet for 3 months after the soft diet for 1 month, had more Fos-ir cells than the mice fed the soft diet alone (p<0.05). The hard-diet feeding also recovered odor responses at the Pir (Figure 3E-H). One-factor ANOVA revealed a main effect between diets (F(2, 12) = 6.63, p<0.05). Fisher's PLSD post-hoc testing indicated that the Pir in mice fed the hard diet for 3 months after the soft diet for 1 month had more Fos-ir cells than the Pir in mice fed the soft diet alone (p<0.05).


Hard-diet feeding recovers neurogenesis in the subventricular zone and olfactory functions of mice impaired by soft-diet feeding.

Utsugi C, Miyazono S, Osada K, Sasajima H, Noguchi T, Matsuda M, Kashiwayanagi M - PLoS ONE (2014)

Fos-ir cells after exposure to urinary odor in the OB and Pir.Sagittal sections of the OB and Pir after exposure of mice fed only a hard diet (A and E), only a soft diet (B and F), or a hard diet for 3 months after a soft diet for 1 month (C and G) to urinary odor, respectively. Scale bar: 200 µm (C), 500 µm (G). D: The numbers of Fos-ir cells in the mitral cell layer in 500 µm thickness from Figure 108 of the mouse atlas (lateral 0.84 mm) of the OB to the lateral side of mice fed only the hard diet (black column; n = 5), only the soft diet (white column; n = 5), or the hard diet after the soft diet (gray column; n = 5). H: The number of Fos-ir cells in 400 µm thickness from Figure 114 of the mouse atlas (lateral 1.56 mm) of the Pir of mice fed only the hard diet (black column; n = 5), only the soft diet (white column; n = 5), or the hard diet after the soft diet (gray column; n = 5). *: p<0.05; **: p<0.005.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4016307&req=5

pone-0097309-g003: Fos-ir cells after exposure to urinary odor in the OB and Pir.Sagittal sections of the OB and Pir after exposure of mice fed only a hard diet (A and E), only a soft diet (B and F), or a hard diet for 3 months after a soft diet for 1 month (C and G) to urinary odor, respectively. Scale bar: 200 µm (C), 500 µm (G). D: The numbers of Fos-ir cells in the mitral cell layer in 500 µm thickness from Figure 108 of the mouse atlas (lateral 0.84 mm) of the OB to the lateral side of mice fed only the hard diet (black column; n = 5), only the soft diet (white column; n = 5), or the hard diet after the soft diet (gray column; n = 5). H: The number of Fos-ir cells in 400 µm thickness from Figure 114 of the mouse atlas (lateral 1.56 mm) of the Pir of mice fed only the hard diet (black column; n = 5), only the soft diet (white column; n = 5), or the hard diet after the soft diet (gray column; n = 5). *: p<0.05; **: p<0.005.
Mentions: Next, we explored the effect of hard-diet feeding for 3 months on responses to odors at the OB and piriform cortex (Pir) of mice fed a soft diet for 1 month. Exposure to urinary odor excreted by males induced Fos-immunoreactivity (Fos-ir), which is correlated with cellular activity, in various cells of the OB of mice fed the hard diet (Figure 3A). In contrast, Fos-immunoreactivity at the OB of mice fed the soft diet was low (Figure 3B). In mice fed the hard diet for 3 months after the soft diet for 1 month, exposure to the urinary odor induced levels of Fos-ir cells at the OB that were similar to the levels in mice fed only the hard diet (Figure 3C). Figure 3D shows the number of Fos-ir cells at the mitral cell layer of the OB after exposure to urinary odor. The data from each group were cast into a one-factor ANOVA as follows: hard, soft, or hard after soft diet. One factor ANOVA revealed the main effect of diet (F(2, 12) = 4.78, p<0.05). Fisher's PLSD post-hoc testing indicated that the mitral cell layer of the OB in mice fed the hard diet for 3 months after the soft diet for 1 month, had more Fos-ir cells than the mice fed the soft diet alone (p<0.05). The hard-diet feeding also recovered odor responses at the Pir (Figure 3E-H). One-factor ANOVA revealed a main effect between diets (F(2, 12) = 6.63, p<0.05). Fisher's PLSD post-hoc testing indicated that the Pir in mice fed the hard diet for 3 months after the soft diet for 1 month had more Fos-ir cells than the Pir in mice fed the soft diet alone (p<0.05).

Bottom Line: Recent studies have shown that a reduction of mastication impairs both neurogenesis in the hippocampus and brain functions.Avoidance of butyric acid was reduced by the soft-diet feeding.The present results suggest that feeding with a hard diet improves neurogenesis in the SVZ, which in turn enhances olfactory function at the OB.

View Article: PubMed Central - PubMed

Affiliation: Department of Oral and Maxillofacial Surgery, Asahikawa Medical University, Asahikawa, Japan; Department of Sensory Physiology, Asahikawa Medical University, Asahikawa, Japan.

ABSTRACT
The subventricular zone (SVZ) generates an immense number of neurons even during adulthood. These neurons migrate to the olfactory bulb (OB) and differentiate into granule cells and periglomerular cells. The information broadcast by general odorants is received by the olfactory sensory neurons and transmitted to the OB. Recent studies have shown that a reduction of mastication impairs both neurogenesis in the hippocampus and brain functions. To examine these effects, we first measured the difference in Fos-immunoreactivity (Fos-ir) at the principal sensory trigeminal nucleus (Pr5), which receives intraoral touch information via the trigeminal nerve, when female adult mice ingested a hard or soft diet to explore whether soft-diet feeding could mimic impaired mastication. Ingestion of a hard diet induced greater expression of Fos-ir cells at the Pr5 than did a soft diet or no diet. Bromodeoxyuridine-immunoreactive (BrdU-ir) structures in sagittal sections of the SVZ and in the OB of mice fed a soft or hard diet were studied to explore the effects of changes in mastication on newly generated neurons. After 1 month, the density of BrdU-ir cells in the SVZ and OB was lower in the soft-diet-fed mice than in the hard-diet-fed mice. The odor preferences of individual female mice to butyric acid were tested in a Y-maze apparatus. Avoidance of butyric acid was reduced by the soft-diet feeding. We then explored the effects of the hard-diet feeding on olfactory functions and neurogenesis in the SVZ of mice impaired by soft-diet feeding. At 3 months of hard-diet feeding, avoidance of butyric acid was reversed and responses to odors and neurogenesis were recovered in the SVZ. The present results suggest that feeding with a hard diet improves neurogenesis in the SVZ, which in turn enhances olfactory function at the OB.

Show MeSH
Related in: MedlinePlus