Elastic fibres in the vesicourethral junction and urethra of the guinea pig: quantification with computerised image analysis

Abstract

Elastic fibres, which are intimately associated with collagen, a major component of the urethra, have been assumed to contribute to the resting urethral closure pressure. The Miller stain for elastin was used to demonstrate elastic fibres in cryostat sections of guinea pig bladder base, vesicourethral junction (VUJ) and urethra. Computerised image analysis was employed to objectively quantify these fibres. Both male and female guinea pigs showed significantly greater amounts of circularly disposed elastic fibres in the VUJ than in the other 2 regions examined. This particular disposition of fibres may be responsible for imparting resiliency and plasticity to the VUJ, allowing it to distend and recoil repeatedly in response to urine outflow. Furthermore, the elastic fibres may be partly responsible for the passive occlusive force in this region. Elastic fibres in the distal urethra were not quantified because of their relative paucity. Sagittal sections of the urethra revealed a mass of longitudinally arranged elastic fibres localised almost exclusively within the mucosa, submucosa and longitudinal smooth muscle layer. Functionally, this arrangement may exist to facilitate urethral length changes that occur in micturition.

Immunohistochemical Localization of Elastic System Fibres in the Canine Prostate

“…A similar increase of elastic fibres was reported in the vesicourethral junction and urethra of the guinea pig [2] and also in the cat [4]. An abundance of elastic fibres amongst the smooth muscle bundles associated with the human male membranous urethral sphincter has been reported by H o et al [7].…”

“…D a s s e t al. [2] considered the elastic fibres associated with the smooth muscle bundles of the urethra suitable for both uniting the contractile force of the smooth muscle bundles to shorten the urethra, as well as augmenting passive recoil of the longitudinal smooth muscle bundles, hence restoring the urethral in length. The number and organization of elastic tissue change in the case of benign prostatic hyperplasia where the larger proportion of elastin in the area of the urethra and at the base of prostate was noted [12].…”

“…[2]. M u r a k u m o et al [11] in their scanning electron microscopic study,observed three dimensional arrangement of collagen and elastin fibres in the human urinary bladder.…”

Efeitos do envelhecimento nos componentes fibroelásticos da junção vésico-uretral de ratos wistar.

“…Dass et al (1999) Bump et al (1988) demonstrando que os elementos fibroelásticos apresentaram efeitos na pressão uretral com perfil equivalente ao mostrado pela camada vascular.…”

“…A análise deste estudo, representado pelas figuras de 10 a 33, demonstra que as fibras elásticas maduras são formadas por componente material amorfo eletrodenso, compacto e abundante (elastina), as fibras elaunínicas por escasso material amorfo (elastina) e componente microtubular em maior quantidade e as oxitalânicas compostas apenas por componente microtubular formando feixes e dispostos paralelamente não estando associados a elastina. (GAWLIK, 1965;GOLDFISCHE et al, 1983), pele (COTTA-PEREIRA et al, 1975), periodonto (FULLMER e LILIE, 1958FULLMER, 1978;SAWADAculean et al, 2006, SCULEAN et al, 1997, ducto deferente (PANIAGUA et al, 1983), cápsula esplênica (SACHETTI, 1996), musculatura lisa (CARVALHO et al, 1997), coração (SOUZA et al, 1996), junção vésico-uretral (AWAD et al, 1976DASS et al, 1999;LÁPIDES, 1958), uretra (BUMP et al, 1988), próstata (KARLINSKI et al, 1976, fáscia transversal iguinal (RODRIGUES, Jr. et al, 1990), pulmão (NIEWOEHNER et al, 1994), colo vesical (ROTHER et al, 1996), neste estudo também confirmamos a distribuição das fibras do sistema elástico na junção vésico-uretral concordando com os achados de Lápides ( Everts et al (1998) ;Fullmer et al, (1974) Gawlik (1965Sakai et al, 1986;Sims et al (1973Sims et al ( , 1975Takagi et al (1989) relataram que as fibras que compõem o sistema elástico são evidenciadas, na microscopia de luz, pelos métodos de coloração hematoxilina férrica (Verhoeff), resorcinafucsina (Weigert) e resorcina-fucsina com prévia oxidação (Weigert-Oxona), corando fibras elásticas maduras, fibras elásticas maduras e elaunínicas, fibras elásticas maduras, elaunínicas e oxitalânicas, respectivamente. Em nosso trabalho, também foi possível identificar e tipificar o sistema elástico, através da microscopia de luz com o uso dessas colorações específicas, em que foi possível realizar a evidenciação das fibras elásticas maduras, elaunínicas e oxitalânicas na JVU, sendo assim observamos que essas fibras estão localizadas em toda a camada muscular da JVU não estando organizadas em feixes, cadeias ou lâminas como aquelas encontradas na pele …”