Development of the urinary system in guinea pig females (Cavia porcellus) / Desenvolvimento do sistema urinário em fêmeas de porquinhos-da-índia (Cavia porcellus)

Guinea pigs are animal models widely used in research related to developmental biology. The objective of this work was to demonstrate the process of formation and differentiation of urinary organs in females of the species in the prenatal period. Four females were used at 25, 30, 45 and >65 DG (days of gestation). The animals were dissected, and then macroscopic and microscopic descriptions of the urinary organs were performed. At 25 DG metanephros were present in the urogenital crest into the abdominal cavity. Collecting ducts and glomerular precursor cells could be visualized. After this period, metanephros underwent microstructural modifications to form the kidneys at the end of the prenatal period. After 30 DG, the renal parenchyma already had a cortex, where the glomerulus and proximal convoluted tubules were present; and the medulla, where distal convoluted tubules, collecting ducts, and pelvis were present. The pelvis of each kidney was drained by the ureters. The ureters also underwent tissue differentiation to be differentiated (mucosa with transitional epithelium and lamina propria of connective tissue, muscular, and adventitia) at the end of the prenatal period. The urinary vesicle also underwent tissue changes to form the tunics similar to those found in the ureters, with emphasis on the greater volume of the muscular tunica and the lamina propria that constituted the submucosa in this organ. The pelvic urethra was evidenced by a mucosa lined by transitional epithelium, submucosa, muscular and adventitia. Finally, a partial clitoral urethra and a urethral meatus in the prepuce of the clitoris were also evidenced. The urethral channel began to form with the emergence of the urethral plate and the urethral groove at 30 DG and thereafter with the fusion of the urethral folds to form a partially channeled urethra in the clitoris. A urethral meatus was observed in the most distal portion of the clitoral tissue, formed by the fusion of the prepuce. It is concluded that the urinary organs of guinea pig have similar development to that described in domestic animals, except for the partial clitoral urethra and evident urethral meatus.(AU)

Os porquinhos-da-índia são modelos animais amplamente utilizados em pesquisas relacionadas a biologia do desenvolvimento. O objetivo deste trabalho foi demonstrar o processo de formação e diferenciação dos órgãos urinários em fêmeas da espécie no período pré-natal. Foram utilizadas quatro fêmeas aos 25, 30, 45 e >65 DG (dias de gestação). Os animais foram dissecados e então, realizaram-se descrições macroscópicas e microscópicas dos órgãos urinários. Aos 25 DG os metanefros estavam presentes na crista urogenital da cavidade abdominal. Podiam ser visualizados ductos coletores e células precursoras glomerulares. Após este período, os metanefros sofreram modificações microestruturais para formar os rins ao final do período pré-natal. Após os 30 DG, o parênquima renal já apresentava um córtex, onde estavam presentes os glomérulos e túbulos convolutos proximais, e a medula onde estavam presentes túbulos convolutos distais, ductos coletores e a pelve. A pelve de cada rim era drenada pelos ureteres. Os ureteres também sofreram diferenciação tecidual para estarem com suas túnicas diferenciadas (mucosa com epitélio de transição e lâmina própria de tecido conjuntivo; muscular; e, adventícia) ao final do período pré-natal. A vesícula urinária também passou por modificações teciduais para formar as túnicas semelhantes as dos ureteres, com destaque para o maior volume da túnica muscular e a lâmina própria que constituiu a submucosa neste órgão. Uma uretra pélvica foi evidenciada por uma mucosa revestida por epitélio de transição, submucosa, muscular e adventícia. Por último, uma uretra parcialmente clitoriana e um meato uretral no prepúcio do clitóris também foi evidenciado. O canal uretral começou a se formar com o aparecimento da placa uretral e do sulco uretral aos 30 DG e posteriormente com a fusão das pregas uretrais para formar uma uretra parcialmente canalizada no clitóris. Observou-se um meato uretral na porção mais distal do tecido clitoriano, formado pela fusão do prepúcio. Conclui-se que os órgãos urinários do porquinho-da-índia possuem desenvolvimento semelhante ao descrito em animais domésticos, com exceção da uretra parcialmente clitoriana e do meato uretral evidente.(AU)

Prenatal development of pelvic urethra in goat (Capra hircus) / Desarrollo prenatal de la uretra pélvica en cabras (Capra hircus)

The study was conducted on the embryo/foeti of goat from 0-150 days of gestation, divided into group I (0-30 days), group II (31-60 days), group III (61-90 days), group IV (91-120 days) and group V (121-150 days of gestation). In group I whole embryo was processed and serial sections were cut whereas, in rest of the groups, pelvic urethra was dissected out and the tissues from the representative areas were used for the study. Grossly, on 49.33 days of gestation the pelvic urethra was present in the form of smooth cylindrical tube, approximately 4mm in length. The primordial of vesicular gland and bulbourethral gland appeared on 52 days of gestation at the junction of neck of urinary bladder with pelvic urethra and at the junction of pelvic and penile urethra respectively. The length, width, height and circumference of pelvic urethra increased with increased in gestation period, however the length (7 times) and circumference (9 times) increased maximum from group II to group V. The morphometrical parameters (length, width, height and circumference) of pelvic urethra were significantly correlated with the age and weight of foetus throughout gestation period. The colliculus seminalis, which was present in the form of ridge on 72 days of gestation, became distinct on 75 days of gestation. Histologically, on 28 days of gestation, the urogenital sinus was present as a cleft with in the cluster of cells. On 55 days of gestation, the process of luminization started with in the wall of pelvic urethra, which started first in its caudal part and proceeded cranially. All the four layers (Tunica mucosa, submucosa, muscularis and adventitia) were distinct. The lumen was lined with 3-4 layers of stratified epitheliumin group II but in group III on 70 days of gestation and beyond this distinct transitional epithelium was present. The formation of cavernous spaces started at 59 days of gestation...

El estudio se realizó sobre embriones/fetos de cabras de 0 a 150 días de gestación, divididos en grupo I (0-30 días), grupo II (31-60 días), el grupo III (61-90 días), grupo IV (91 a 120 días) y grupo V (121-150 días de gestación). En el grupo I embriones enteros fueron procesados mediante cortes seriados, en el resto de los grupos, la uretra pélvica fue disecada y los tejidos de las áreas representativas se utilizaron para su estudio. Macroscópicamente, a los 49,33 días de gestación de la uretra pélvica estaba presente en forma de tubo cilíndrico liso, aproximadamente 4 mm de longitud. El primordio de la glándula vesicular y la glándula bulbouretral apareció a los 52 días de gestación en el cruce de cuello de la vejiga urinaria con la uretra pélvica y el cruce de la uretra pélvica y pene respectivamente. La longitud, ancho, alto y circunferencia de la uretra pélvica aumentó con el avance del período de gestación, sin embargo, la longitud (7 veces) y el perímetro (9 veces) aumentó en el grupo II y V. Los parámetros morfométricos (longitud, ancho, alto y circunferencia) de la uretra pélvica se correlacionaron significativamente con la edad y el peso del feto durante toda la gestación. El colículo seminal, que estaba presente en la forma de cresta a los 72 días de gestación, se mostró distinta a los 75 días de gestación. Histológicamente, en 28 días de gestación, el seno urogenital estaba presente como una hendidura con un grupo de células. En 55 días de gestación, el proceso de luminización comenzó en la pared de la uretra pélvica, que comenzó en su primera parte caudal y procedió cranealmente. Las cuatro capas (túnica mucosa, submucosa, muscular y adventicia) eran distintas. La luz estaba cubierta con 3-4 capas de epitelio estratificado en el grupo II, pero en el grupo III a los 70 días de gestación y más, un epitelio de transición distinto estuvo presente. La formación de espacios cavernosos comenzó a los 59 días de gestación...