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Estrogen depletion results in nanoscale morphology changes in dermal collagen.

Fang M, Liroff KG, Turner AS, Les CM, Orr BG, Holl MM - J. Invest. Dermatol. (2012)

Bottom Line: In addition, the overall width of the distribution, both values above and below the mean, was found to be increased.The change in width due to an increase in lower values of D-spacings was previously reported for ovine bone; however, this report demonstrates that the effect is also present in non-mineralized collagen fibrils.A nonparametric Kolmogorov-Smirnov test of the cumulative density function indicates a statistical difference in the sham and OVX D-spacing distributions (P<0.01).

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, University of Michigan, Ann Arbor, Michigan, USA.

ABSTRACT
Tissue cryo-sectioning combined with atomic force microscopy imaging reveals that the nanoscale morphology of dermal collagen fibrils, quantified using the metric of D-periodic spacing, changes under the condition of estrogen depletion. Specifically, a new subpopulation of fibrils with D-spacings in the region between 56 and 59 nm is present 2 years following ovariectomy in ovine dermal samples. In addition, the overall width of the distribution, both values above and below the mean, was found to be increased. The change in width due to an increase in lower values of D-spacings was previously reported for ovine bone; however, this report demonstrates that the effect is also present in non-mineralized collagen fibrils. A nonparametric Kolmogorov-Smirnov test of the cumulative density function indicates a statistical difference in the sham and OVX D-spacing distributions (P<0.01).

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Histogram and cumulative distribution function of D-Periodic spacings from Sham and OVX ovine skin (each contains five animals). Panel a shows the histogram representation of D-periodic gap/overlap spacings from sham and OVX ovine skin (1 nm bin size). Panel b is the Cumulative Distribution Function (CDF) calculated from each group. Kolmogrov-Smirnov test performed the data distributions indicates significant difference (p < 0.001).
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Figure 3: Histogram and cumulative distribution function of D-Periodic spacings from Sham and OVX ovine skin (each contains five animals). Panel a shows the histogram representation of D-periodic gap/overlap spacings from sham and OVX ovine skin (1 nm bin size). Panel b is the Cumulative Distribution Function (CDF) calculated from each group. Kolmogrov-Smirnov test performed the data distributions indicates significant difference (p < 0.001).

Mentions: Examining the population histogram (Figure 3A) revealed that the sham D-spacing distribution spans between 59 and 66 nm whereas the OVX population spans between 56 and 67 nm. The major difference between these populations arises from the percentage of fibrils with D-spacings from 56 to 59 nm – 14.6% in OVX group and 1.6% in Sham group. Note that these changes in distribution do not have a significant impact on the mean D-spacing values which are 61.9 nm for the OVX and 62.3 nm for the sham specimens. The distributions are not strictly Gaussian and the OVX distribution in particular appears bimodal, making the use of the mean value statistically incorrect. We provide it here so that a rough comparison to previous literature can be made; however, to correctly analyze the data a non-parametric method must be employed.


Estrogen depletion results in nanoscale morphology changes in dermal collagen.

Fang M, Liroff KG, Turner AS, Les CM, Orr BG, Holl MM - J. Invest. Dermatol. (2012)

Histogram and cumulative distribution function of D-Periodic spacings from Sham and OVX ovine skin (each contains five animals). Panel a shows the histogram representation of D-periodic gap/overlap spacings from sham and OVX ovine skin (1 nm bin size). Panel b is the Cumulative Distribution Function (CDF) calculated from each group. Kolmogrov-Smirnov test performed the data distributions indicates significant difference (p < 0.001).
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Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3375339&req=5

Figure 3: Histogram and cumulative distribution function of D-Periodic spacings from Sham and OVX ovine skin (each contains five animals). Panel a shows the histogram representation of D-periodic gap/overlap spacings from sham and OVX ovine skin (1 nm bin size). Panel b is the Cumulative Distribution Function (CDF) calculated from each group. Kolmogrov-Smirnov test performed the data distributions indicates significant difference (p < 0.001).
Mentions: Examining the population histogram (Figure 3A) revealed that the sham D-spacing distribution spans between 59 and 66 nm whereas the OVX population spans between 56 and 67 nm. The major difference between these populations arises from the percentage of fibrils with D-spacings from 56 to 59 nm – 14.6% in OVX group and 1.6% in Sham group. Note that these changes in distribution do not have a significant impact on the mean D-spacing values which are 61.9 nm for the OVX and 62.3 nm for the sham specimens. The distributions are not strictly Gaussian and the OVX distribution in particular appears bimodal, making the use of the mean value statistically incorrect. We provide it here so that a rough comparison to previous literature can be made; however, to correctly analyze the data a non-parametric method must be employed.

Bottom Line: In addition, the overall width of the distribution, both values above and below the mean, was found to be increased.The change in width due to an increase in lower values of D-spacings was previously reported for ovine bone; however, this report demonstrates that the effect is also present in non-mineralized collagen fibrils.A nonparametric Kolmogorov-Smirnov test of the cumulative density function indicates a statistical difference in the sham and OVX D-spacing distributions (P<0.01).

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, University of Michigan, Ann Arbor, Michigan, USA.

ABSTRACT
Tissue cryo-sectioning combined with atomic force microscopy imaging reveals that the nanoscale morphology of dermal collagen fibrils, quantified using the metric of D-periodic spacing, changes under the condition of estrogen depletion. Specifically, a new subpopulation of fibrils with D-spacings in the region between 56 and 59 nm is present 2 years following ovariectomy in ovine dermal samples. In addition, the overall width of the distribution, both values above and below the mean, was found to be increased. The change in width due to an increase in lower values of D-spacings was previously reported for ovine bone; however, this report demonstrates that the effect is also present in non-mineralized collagen fibrils. A nonparametric Kolmogorov-Smirnov test of the cumulative density function indicates a statistical difference in the sham and OVX D-spacing distributions (P<0.01).

Show MeSH
Related in: MedlinePlus