Qualitative and quantitative characterization of the Rhesus monkey (Macaca mulatta) penis

ABSTRACT Background: Knowledge of the anatomy of laboratory animals is important for experimental research. Erectile dysfunction has been studied using the penises of different laboratory animals such as rats, mice, rabbits, dogs, etc. However, these animals have penises with different characterist...

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Main Authors: Marcelo Abidu-Figueiredo, Edilaine F. Alves, Carla B. M. Gallo, Waldemar S. Costa, Luciano A. Favorito, Francisco J. B. Sampaio
Format: Article
Language:English
Published: Sociedade Brasileira de Urologia 2025-04-01
Series:International Brazilian Journal of Urology
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Online Access:http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-55382025000300404&lng=en&tlng=en
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author Marcelo Abidu-Figueiredo
Edilaine F. Alves
Carla B. M. Gallo
Waldemar S. Costa
Luciano A. Favorito
Francisco J. B. Sampaio
author_facet Marcelo Abidu-Figueiredo
Edilaine F. Alves
Carla B. M. Gallo
Waldemar S. Costa
Luciano A. Favorito
Francisco J. B. Sampaio
author_sort Marcelo Abidu-Figueiredo
collection DOAJ
description ABSTRACT Background: Knowledge of the anatomy of laboratory animals is important for experimental research. Erectile dysfunction has been studied using the penises of different laboratory animals such as rats, mice, rabbits, dogs, etc. However, these animals have penises with different characteristics to the human penis. If these differences are not taken into account, the conclusions may be questionable. The Rhesus monkey (Macaca mulatta), due to its similarities to humans, could be a good model. Objective: To characterize and quantify the components of the penis of the Rhesus monkey (Macaca mulatta), qualifying it as a model for experimental studies. Methods: Ten adult Rhesus monkey penises were fixed in 10% buffered formalin and processed for paraffin embedding. Histological sections 5-μm thick were made and stained using histochemical techniques. We assessed the thickness of the tunica albuginea, and in the erectile tissue, the following parameters were analyzed: in the corpus cavernosum (CC): total area, area densities of collagen fibers, muscle fibers and elastic system fibers; in the corpus spongiosum (CS): area densities of collagen fibers, muscle fibers and elastic system fibers. Histomorphometric analyses were carried out on photomicrographs by using ImageJ software. Results: The penis of the Rhesus monkey (Macaca mulatta) has a single CC. The tunica albuginea was thicker in the dorsal region (1.11 ± 0.03 mm) than in the ventral region (0.87 ± 0.01 mm). The quantitative analysis of the CC showed the following values: total area (20.33 ± 5.67 mm²), collagen fibers (24.00 ± 4.00%), muscle fibers (31.52 ± 9.93%) and elastic system fibers (8.46 ± 3.20%). The quantitative analysis of the CS showed the following values: collagen fibers (52.50 ± 11.76%), muscle fibers (10.50 ± 6.36%) and elastic system fibers (15.07 ± 4.78%). Conclusion: The predominance of muscle tissue over connective tissue in the corpus cavernosum, similar to what is observed in humans, qualifies the Rhesus monkey penis as a good experimental model for erectile dysfunction.
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publisher Sociedade Brasileira de Urologia
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spelling doaj-art-83d285d2dec449ad9b16e49b06263d232025-08-20T02:14:38ZengSociedade Brasileira de UrologiaInternational Brazilian Journal of Urology1677-61192025-04-0151310.1590/s1677-5538.ibju.2025.9906Qualitative and quantitative characterization of the Rhesus monkey (Macaca mulatta) penisMarcelo Abidu-FigueiredoEdilaine F. AlvesCarla B. M. GalloWaldemar S. CostaLuciano A. FavoritoFrancisco J. B. Sampaiohttps://orcid.org/0000-0001-9087-9319ABSTRACT Background: Knowledge of the anatomy of laboratory animals is important for experimental research. Erectile dysfunction has been studied using the penises of different laboratory animals such as rats, mice, rabbits, dogs, etc. However, these animals have penises with different characteristics to the human penis. If these differences are not taken into account, the conclusions may be questionable. The Rhesus monkey (Macaca mulatta), due to its similarities to humans, could be a good model. Objective: To characterize and quantify the components of the penis of the Rhesus monkey (Macaca mulatta), qualifying it as a model for experimental studies. Methods: Ten adult Rhesus monkey penises were fixed in 10% buffered formalin and processed for paraffin embedding. Histological sections 5-μm thick were made and stained using histochemical techniques. We assessed the thickness of the tunica albuginea, and in the erectile tissue, the following parameters were analyzed: in the corpus cavernosum (CC): total area, area densities of collagen fibers, muscle fibers and elastic system fibers; in the corpus spongiosum (CS): area densities of collagen fibers, muscle fibers and elastic system fibers. Histomorphometric analyses were carried out on photomicrographs by using ImageJ software. Results: The penis of the Rhesus monkey (Macaca mulatta) has a single CC. The tunica albuginea was thicker in the dorsal region (1.11 ± 0.03 mm) than in the ventral region (0.87 ± 0.01 mm). The quantitative analysis of the CC showed the following values: total area (20.33 ± 5.67 mm²), collagen fibers (24.00 ± 4.00%), muscle fibers (31.52 ± 9.93%) and elastic system fibers (8.46 ± 3.20%). The quantitative analysis of the CS showed the following values: collagen fibers (52.50 ± 11.76%), muscle fibers (10.50 ± 6.36%) and elastic system fibers (15.07 ± 4.78%). Conclusion: The predominance of muscle tissue over connective tissue in the corpus cavernosum, similar to what is observed in humans, qualifies the Rhesus monkey penis as a good experimental model for erectile dysfunction.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-55382025000300404&lng=en&tlng=enPenisMacaca mulattaModels, Theoreticalanatomy and histology [Subheading]
spellingShingle Marcelo Abidu-Figueiredo
Edilaine F. Alves
Carla B. M. Gallo
Waldemar S. Costa
Luciano A. Favorito
Francisco J. B. Sampaio
Qualitative and quantitative characterization of the Rhesus monkey (Macaca mulatta) penis
International Brazilian Journal of Urology
Penis
Macaca mulatta
Models, Theoretical
anatomy and histology [Subheading]
title Qualitative and quantitative characterization of the Rhesus monkey (Macaca mulatta) penis
title_full Qualitative and quantitative characterization of the Rhesus monkey (Macaca mulatta) penis
title_fullStr Qualitative and quantitative characterization of the Rhesus monkey (Macaca mulatta) penis
title_full_unstemmed Qualitative and quantitative characterization of the Rhesus monkey (Macaca mulatta) penis
title_short Qualitative and quantitative characterization of the Rhesus monkey (Macaca mulatta) penis
title_sort qualitative and quantitative characterization of the rhesus monkey macaca mulatta penis
topic Penis
Macaca mulatta
Models, Theoretical
anatomy and histology [Subheading]
url http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1677-55382025000300404&lng=en&tlng=en
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