Research Article: Stereological analysis of elastic fibers of the corpus cavernosum of rats during the aging process1

Date Published: October 14, 2019

Publisher: Sociedade Brasileira para o Desenvolvimento da Pesquisa em

Author(s): Thiago Hota, Fernando Lorenzini, Eduardo Felippe Melchioretto, Marcelo Zeni, Djanira Aparecida da Luz Veronez, Rogério de Fraga.


To evaluate changes in the quantity of elastic fibers in the corpora
cavernosa of rats during the natural aging process, and to assess the degree
of this change by determining volumetric density (Vv) at different ages via
stereological analysis.

Forty-eight rats, raised under similar conditions, were subjected to the
natural aging process and divided into four groups (G1 to G4), according to
age at the time of penectomy (6, 9, 12, and 24 months, respectively).
Histological sections of the middle segment of the penis were stained with
Weigert’s resorcin-fuchsin, and the volumetric density (Vv) of elastic
fibers of the corpora cavernosa were determined via stereological

There were no statistically significant differences in Vv among groups G1,
G2, and G3. These three groups were therefore considered as a single group.
The mean Vv of this group showed a statistically significant reduction
compared to that of G4 (0.16 vs. 0.11, p<0.05). Natural aging in rats was responsible for a reduction in volumetric density of elastic fibers of the corpora cavernosa (approximately 30% decrease in Vv) during senescence.

Partial Text

Erectile dysfunction (ED) is defined as the inability to initiate, maintain, and
conclude a satisfactory sexual relationship. According to the Diagnostic and
Statistical Manual of Mental Disorders (DSM)-5, symptoms must last for a minimum
time of 6 months for diagnosis of ED1 . The incidence of ED is high, affecting approximately 152 million men worldwide2 .

This study followed the ethical principles of animal experimentation established by
the Brazilian College of Animal Experimentation (COBEA) and the norms of the
Canadian Council on Animal Care (1993). It was previously approved by the Ethics
Committee on Animal Experimentation (CEEA), of the Sector of Biological Sciences of
the Universidade Federal do Paraná, as part of the project “Anatomical and
physiological evaluation of male urogenital aging,” process No.

Histological section fields were found to be homogeneous. The positive points of the
field test, which are those contacted by elastic fibers in each random vertical
section of the corpus cavernosum, are shown in Figure
3 numbered from 1 to 5. Five fields were analyzed and labeled “a” to

The use of stereology in genitourinary tract studies allows the quantification of its
elements, and therefore brings greater objectivity to the analysis. Pinheiro
et al .8 demonstrated the relevance of stereological analysis in determining the
relative densities of muscle, collagen, and elastic fibers of the corpus cavernosum
of rats at 4 months of age, as well as its effectiveness in describing the behavior
of the corpus cavernosum extracellular matrix in pathological states. Also using
stereology, Abidu-Figueiredo et al.9 proved the effects of diabetes mellitus on the corpus cavernosum of rabbits
and showed the reduction of elastic fibers and collagen. In our experience,
stereology is a reliable tool, the capacity to provide homogeneous positive
test-points for rats at the same age, as well as the capacity to confirm our valid
hypothesis in agreement with literature data, base this reliability.

The natural aging process in rats was responsible for changes in the volumetric
density of elastic fibers of the trabeculae of the corpora cavernosa, as evidenced
by a 30% decrease in volumetric density during senescence.




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