title: Effects of chronic stress on penile corpus cavernosum of rats.
abstract: The objective of this study was to investigate structural changes in the  penile corpus cavernosum of prepubertal chronically stressed rats. Eight  Wistar rats were assigned into the stress group (SG) and were submitted to 2  hours of tube restraint daily, from the fourth to the ninth week of life.  Another 7 rats were used as the control group (CG). All animals were weighed  weekly. At day 64, animals were sacrificed by anesthetic overdose, blood was  collected for testosterone concentration by radioimmunoassay, and penis and  adrenal were collected. Adrenal mass index and testosterone serum levels were  used to assess the efficacy of the stress stimulus. The surface density of  connective tissue and smooth muscle fibers of corpus cavernosum were measured  on Masson trichromic-stained slices. Picrosirius red-stained  slices were assessed under polarized light for different types of collagen.  The Student's t test was applied for mean comparisons, with  P < .05 considered significant. Testosterone serum concentrations  decreased and adrenal mass index increased, confirming the effectiveness of  the stress protocol. Smooth muscle fibers of corpus cavernosum decreased from  14.07% (CG) to 8.98% (SG) (P = .02), and connective tissue increased  from 53.66% (CG) to 64.47% (SG) (P = .01). Also, there was a higher  level of type I collagen in the SG animals compared with the CG. Stress  stimuli induced structural changes in the corpus cavernosum of rats suggestive  of penile fibrosis, which may play a role in erection dysfunction.
authors.affiliation: Urogenital Research Unit, State University of Rio de Janeiro, Av 28 de Setembro, 87, Fundos, Vila Isabel, Rio de Janeiro, RJ, Brazil. diogobenchimol@gmail.com
authors.forename: Diogo B
authors.initials: DB
authors.lastname: de Souza
authors.forename: Dilson
authors.initials: D
authors.lastname: Silva
authors.forename: Celia M
authors.initials: CM
authors.lastname: Cortez
authors.forename: Waldemar S
authors.initials: WS
authors.lastname: Costa
authors.forename: Francisco J B
authors.initials: FJ
authors.lastname: Sampaio
mesh_terms: D000375:Aging; D000818:Animals; D024042:Collagen Type I / Q000032:analysis; D003238:Connective Tissue / Q000737:chemistry; D008297:Male; D032389:Myocytes, Smooth Muscle; D010413:Penis / Q000737:chemistry* / Q000473:pathology*; D051381:Rats; D017208:Rats, Wistar; D012149:Restraint, Physical; D013315:Stress, Psychological / Q000503:physiopathology*; D013739:Testosterone / Q000097:blood
chemical_list: D024042:Collagen Type I; D013739:Testosterone