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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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Related in: MedlinePlus

Calculation of expression levels for OPG, RANKL and their ratio.Analysis using qRT-PCR revealed that the relative expression of OPG (panel A) and RANKL (panel B) were not significantly different (p = 0.38 and p = 0.14 respectively) between females and males. Subsequent analysis of the OPG:RANKL ratio (panel 5C) also did not reveal a gender bias (p = 0.36). Error bars denote the SEM.
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pone-0063952-g005: Calculation of expression levels for OPG, RANKL and their ratio.Analysis using qRT-PCR revealed that the relative expression of OPG (panel A) and RANKL (panel B) were not significantly different (p = 0.38 and p = 0.14 respectively) between females and males. Subsequent analysis of the OPG:RANKL ratio (panel 5C) also did not reveal a gender bias (p = 0.36). Error bars denote the SEM.

Mentions: The relative expression of OPG and RANKL were calculated using qRT-PCR and the ratio determined for each of the sexes. A significant difference was not detected between females and males in the expression level of OPG (p = 0.38, Figure 5A) and RANKL (p = 0.14, Figure 5B). Consequently, the OPG:RANKL ratio (Figure 5C) also did not reveal a gender bias, which was 47.5∶1±30.9 for females and 34.6∶1±9.2 for males (p = 0.36).


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)

Calculation of expression levels for OPG, RANKL and their ratio.Analysis using qRT-PCR revealed that the relative expression of OPG (panel A) and RANKL (panel B) were not significantly different (p = 0.38 and p = 0.14 respectively) between females and males. Subsequent analysis of the OPG:RANKL ratio (panel 5C) also did not reveal a gender bias (p = 0.36). Error bars denote the SEM.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0063952-g005: Calculation of expression levels for OPG, RANKL and their ratio.Analysis using qRT-PCR revealed that the relative expression of OPG (panel A) and RANKL (panel B) were not significantly different (p = 0.38 and p = 0.14 respectively) between females and males. Subsequent analysis of the OPG:RANKL ratio (panel 5C) also did not reveal a gender bias (p = 0.36). Error bars denote the SEM.
Mentions: The relative expression of OPG and RANKL were calculated using qRT-PCR and the ratio determined for each of the sexes. A significant difference was not detected between females and males in the expression level of OPG (p = 0.38, Figure 5A) and RANKL (p = 0.14, Figure 5B). Consequently, the OPG:RANKL ratio (Figure 5C) also did not reveal a gender bias, which was 47.5∶1±30.9 for females and 34.6∶1±9.2 for males (p = 0.36).

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