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Prolactin expression in the cochlea of aged BALB/c mice is gender biased and correlates to loss of bone mineral density and hearing loss.

Marano RJ, Tickner J, Redmond SL - PLoS ONE (2013)

Bottom Line: We found that prolactin expression was exclusive to the female mice.However, no gender differences in expression of osteoprotegerin or receptor activator of nuclear factor-kappaB ligand could be found.These results provide a possible mechanism for an age related hearing loss sub-type that is associated with gender and provides clues as to how this gender bias in hearing loss develops.

View Article: PubMed Central - PubMed

Affiliation: Ear Science Institute Australia, Subiaco, Western Australia, Australia. rob.marano@earscience.org.au

ABSTRACT
Prolactin is a versatile hormone with over 300 known functions and predominantly expressed in the pituitary. However, its expression has additionally been found in a number of extrapituitary organs. Recently, we described the expression of prolactin in the inner ear of mice, where it was correlated to age. Previous research has shown prolactin to be linked to abnormal bone metabolism and hearing loss due to changes in morphology of the bony otic capsule. Here we further investigated the relationship between prolactin, hearing loss and cochlea bone metabolism. BALB/c mice were tested for hearing using ABR at 6 and 12 months of age. Bone mineral density of the cochlea was evaluated using microCT scanning. Prolactin expression was calculated using quantitative real time PCR. Expression of the key regulators of bone metabolism, osteoprotegerin and receptor activator of nuclear factor-kappaB ligand were also determined. We found that prolactin expression was exclusive to the female mice. This also correlated to a greater threshold shift in hearing for the females between 6 and 12 months of age. Analyses of the cochlea also show that the bone mineral density was lower in females compared to males. However, no gender differences in expression of osteoprotegerin or receptor activator of nuclear factor-kappaB ligand could be found. Further analysis of cochlea histological sections revealed larger ostocyte lacunae in the females. These results provide a possible mechanism for an age related hearing loss sub-type that is associated with gender and provides clues as to how this gender bias in hearing loss develops. In addition, it has the potential to lead to treatment for this specific type of hearing loss.

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Analysis of cochlea bone.Bone mineral density of the cochlea was calculated for female and male mice using microCT scanning (panel A). Female mice possessed a significantly lower BMD index than male mice (p = 0.014). Subsequent analysis revealed that the average size of the osteocyte lacunae was significantly larger in the female mice compared to the males (p<0.001). Error bars denote the SEM and * indicates a significance of p<0.05.
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pone-0063952-g004: Analysis of cochlea bone.Bone mineral density of the cochlea was calculated for female and male mice using microCT scanning (panel A). Female mice possessed a significantly lower BMD index than male mice (p = 0.014). Subsequent analysis revealed that the average size of the osteocyte lacunae was significantly larger in the female mice compared to the males (p<0.001). Error bars denote the SEM and * indicates a significance of p<0.05.

Mentions: Micro-CT scanning was used to calculate the BMD of cochlea of mice (Figure 4A). The BMD differed significantly (p = 0.014) between the female and male mice, which were 0.133±0.009 and 0.139±.002 respectively. This shows female mice possessed a lower BMD.


Prolactin expression in the cochlea of aged BALB/c mice is gender biased and correlates to loss of bone mineral density and hearing loss.

Marano RJ, Tickner J, Redmond SL - PLoS ONE (2013)

Analysis of cochlea bone.Bone mineral density of the cochlea was calculated for female and male mice using microCT scanning (panel A). Female mice possessed a significantly lower BMD index than male mice (p = 0.014). Subsequent analysis revealed that the average size of the osteocyte lacunae was significantly larger in the female mice compared to the males (p<0.001). Error bars denote the SEM and * indicates a significance of p<0.05.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3646833&req=5

pone-0063952-g004: Analysis of cochlea bone.Bone mineral density of the cochlea was calculated for female and male mice using microCT scanning (panel A). Female mice possessed a significantly lower BMD index than male mice (p = 0.014). Subsequent analysis revealed that the average size of the osteocyte lacunae was significantly larger in the female mice compared to the males (p<0.001). Error bars denote the SEM and * indicates a significance of p<0.05.
Mentions: Micro-CT scanning was used to calculate the BMD of cochlea of mice (Figure 4A). The BMD differed significantly (p = 0.014) between the female and male mice, which were 0.133±0.009 and 0.139±.002 respectively. This shows female mice possessed a lower BMD.

Bottom Line: We found that prolactin expression was exclusive to the female mice.However, no gender differences in expression of osteoprotegerin or receptor activator of nuclear factor-kappaB ligand could be found.These results provide a possible mechanism for an age related hearing loss sub-type that is associated with gender and provides clues as to how this gender bias in hearing loss develops.

View Article: PubMed Central - PubMed

Affiliation: Ear Science Institute Australia, Subiaco, Western Australia, Australia. rob.marano@earscience.org.au

ABSTRACT
Prolactin is a versatile hormone with over 300 known functions and predominantly expressed in the pituitary. However, its expression has additionally been found in a number of extrapituitary organs. Recently, we described the expression of prolactin in the inner ear of mice, where it was correlated to age. Previous research has shown prolactin to be linked to abnormal bone metabolism and hearing loss due to changes in morphology of the bony otic capsule. Here we further investigated the relationship between prolactin, hearing loss and cochlea bone metabolism. BALB/c mice were tested for hearing using ABR at 6 and 12 months of age. Bone mineral density of the cochlea was evaluated using microCT scanning. Prolactin expression was calculated using quantitative real time PCR. Expression of the key regulators of bone metabolism, osteoprotegerin and receptor activator of nuclear factor-kappaB ligand were also determined. We found that prolactin expression was exclusive to the female mice. This also correlated to a greater threshold shift in hearing for the females between 6 and 12 months of age. Analyses of the cochlea also show that the bone mineral density was lower in females compared to males. However, no gender differences in expression of osteoprotegerin or receptor activator of nuclear factor-kappaB ligand could be found. Further analysis of cochlea histological sections revealed larger ostocyte lacunae in the females. These results provide a possible mechanism for an age related hearing loss sub-type that is associated with gender and provides clues as to how this gender bias in hearing loss develops. In addition, it has the potential to lead to treatment for this specific type of hearing loss.

Show MeSH
Related in: MedlinePlus