Adrenal glands of Chinchilla lanigera - study of anatomical features with computed tomography and magnetic resonance imaging

Background: Since chinchilla (Chinchilla lanigera) is frequently used as a laboratory animal, satisfactory data about the imaging anatomical appearance of its adrenal glands, such as their anatomical location and closeness with other abdominal soft tissue and vessels, are important. The aim of this study to determine anatomical features of the chinchilla adrenal gland's using computed tomography and magnetic resonance imaging. Materials, Methods & Results: We used 12 chinchillas (6 males and 6 females), aged 18 months. The animals were in supine recumbency when contrast-enhanced computed tomography (CT) was performed. Transverse, sagittal and dorsal images of the adrenal glands were obtained with iodinated contrast medium, and 3D reconstruction of the obtained images was applied. The craniocaudal (CrCc - length), dorsoventral (DV - height) and lateromedial (LM - width) diameters were measured using an electronic calliper. Magnetic resonance imaging was performed, and coronal T1-weighted images were obtained. The transverse CT anatomical image at the level of the 3rd lumbar vertebra demonstrated the location of the both adrenal glands in accordance with the grey-white scale's variation. The right adrenal gland was hypo-attenuated and elliptic compared to the right kidney and in close contact to it and to the caudal vena cava. The left adrenal gland was oval and at a distance to the abdominal aorta. The dorsal MRI anatomical study of the chinchilla's abdominal organs at a distance of 10 mm from the spine and in a T1-weighted sequence showed that both adrenal glands were retroperitoneal organs. Discussion: Post-contrasted CT defined the topography of both glands. The right adrenal gland has an oval shape and is cranially situated to the left gland, whose shape is cylindrical and elongated. The LM diameter of the right gland is higher than that measured in the left gland. Both DV and CrCc diameters of the right gland are lower compared to those of the left gland. The right adrenal gland is in close contact to the caudal vena cava, the right kidney and the liver, and the left adrenal gland is in a distance to the abdominal aorta. The right adrenal gland was close to the caudal vena cava and the right kidney and medially to the left kidney. The successful comparative analysis of the images in 3D reconstruction and post-contrast CT in 2D allowed us to conclude that 3D reconstruction is suitable to obtain detailed information in a summary form regarding the closeness of the glands and their shape, mainly because the results are in a real time and highly comprehensive. Our data are in in agreement with previous findings about the advantages of 3D reconstruction. The research algorithm applied was based on the dorsal visualization of the glands in T1-weighted sequence, achieving a comprehensive and high-quality MRI imaging of the examined organs in chinchillas. Both adrenal glands were retroperitoneal organs and with low signal. The dorsal MRI anatomical study of the chinchilla's abdominal organs at a distance of 10 mm from the spine and in a T1-weighted sequence showed the whole profile of the right and left glands and the cranial position of the right gland to the left one, the close contact between the right gland and the kidney and the distance between the left gland and the left kidney. The MRI results are detailed and comprehensive for interpretation. In conclusion, the results of the present study are comprehensive, detailed and with high resolution. We present data for the anatomical relationships of the studied organs, their shape and macrometric parameters, concluding that the above mentioned modalities are very important tools for studying the chinchilla's adrenal glands to create a morphological base, which is necessary to investigate specific diseases.

Sistematização e descrição da vascularização arterial da área páleo-palial na superfície do cérebro de chinchila (Chinchilla lanigera) / Systematization and description of arterial vascularization of the paleopallia area on the brain surface of chinchilla (Chinchilla lanigera)

Background: Chinchilla (Chinchilla lanigera) is a small rodent that in recent years has been increasingly used as a laboratory animal by different researchers. Brain irrigation is the object of study by several authors, being chinchilla classifiedas a vertebrobasillary animal, that is, it does not depend on the internal carotid artery to originate its cerebral arterialvascularization. Thus, the objective of this study was to systematize and describe the branches of the rostral, middle andcaudal cerebral arteries that vascularized the paleopallia area of the chinchilla.Materials, Methods & Results: Thirty Chinchilla lanigera brains were used in this study, 17 females and 13 adult malesfrom farms in the municipalities of Viamão and Santa Maria in the state of Rio Grande do Sul, Brazil. The animals wereheparinized, with 5000 IU / animal, and after 30 min were sacrificed with 8 mL / 2.5% sodium thiopental animal, bothintraperitoneally. The thoracic cavity was opened, the cardiac apex sectioned and the aortic arch was cannulated throughthe left ventricle. The arterial system was flushed with 0.9% cooled saline, 100mL / animal and then filled with 603 latexstained red with specific dye. The skin was recessed and a bone window opened in the cranial vault. Thus the pieces werefixed in 20% formaldehyde for seven days and after this period, the brain with a cervical spinal cord segment was removedand ventral schematic drawings of all preparations were prepared. The Veterinary Anatomical Nomina (2017) was usedto name the cerebral arteries and their branches and for the statistical analysis of the results, the percentage calculationwas applied. Brain irrigation in the chinchilla was supplied by the basilar artery, which was formed by anastomosis of theterminal branches of the right and left vertebral arteries, in the most caudal portion of the oblong medulla. The paleopalliaareas corresponded to the olfactory trine, lateral brain fossa, piriform lobe...

Sistematização e descrição da vascularização arterial da área páleo-palial na superfície do cérebro de chinchila (Chinchilla lanigera) / Systematization and description of arterial vascularization of the paleopallia area on the brain surface of chinchilla (Chinchilla lanigera)

Background: Chinchilla (Chinchilla lanigera) is a small rodent that in recent years has been increasingly used as a laboratory animal by different researchers. Brain irrigation is the object of study by several authors, being chinchilla classifiedas a vertebrobasillary animal, that is, it does not depend on the internal carotid artery to originate its cerebral arterialvascularization. Thus, the objective of this study was to systematize and describe the branches of the rostral, middle andcaudal cerebral arteries that vascularized the paleopallia area of the chinchilla.Materials, Methods & Results: Thirty Chinchilla lanigera brains were used in this study, 17 females and 13 adult malesfrom farms in the municipalities of Viamão and Santa Maria in the state of Rio Grande do Sul, Brazil. The animals wereheparinized, with 5000 IU / animal, and after 30 min were sacrificed with 8 mL / 2.5% sodium thiopental animal, bothintraperitoneally. The thoracic cavity was opened, the cardiac apex sectioned and the aortic arch was cannulated throughthe left ventricle. The arterial system was flushed with 0.9% cooled saline, 100mL / animal and then filled with 603 latexstained red with specific dye. The skin was recessed and a bone window opened in the cranial vault. Thus the pieces werefixed in 20% formaldehyde for seven days and after this period, the brain with a cervical spinal cord segment was removedand ventral schematic drawings of all preparations were prepared. The Veterinary Anatomical Nomina (2017) was usedto name the cerebral arteries and their branches and for the statistical analysis of the results, the percentage calculationwas applied. Brain irrigation in the chinchilla was supplied by the basilar artery, which was formed by anastomosis of theterminal branches of the right and left vertebral arteries, in the most caudal portion of the oblong medulla. The paleopalliaareas corresponded to the olfactory trine, lateral brain fossa, piriform lobe...(AU)

Aspectos morfológicos, morfométricos e topográficos do aparelho digestório de Chinchilla Lanigera / Morphological, morphometric and topographical description of the digestive tract in Chinchilla lanigera

O objetivo deste estudo foi o de descrever os aspectos morfológicos e topográficos do Aparelho Digestório (AD) de chinchilas mediante a dissecação de 10 animais. Os segmentos do AD foram coletados e demarcados, seguido de análise volumétrica dos órgãos cavitários, através de injeção de solução salina a 60°C, além da mensuração dos comprimentos dos órgãos tubulares. Nos órgãos parenquimatosos realizou-se a sua pesagem. Durante a análise da disposição dos órgãos, evisceração e medição, observou-se que a cavidade oral é característica de roedores, as glândulas salivares são semelhantes às de lagomorfos e órgãos como esôfago, estômago, duodeno, cólon transverso, fígado, pâncreas e baço apresentam-se dispostos de forma semelhante ao descrito nas outras espécies. Já o jejuno e o cólon descendente foram evidenciados muito extensos e dispostos de forma ondulatória, suspensos no teto da cavidade abdominal. O íleo assemelhou-se ao descrito as outras espécies, porém sua disposição topográfica é da direita para esquerda, direcionando-se ao ceco, o qual constitui-se de duas porções distintas e bem desenvolvidas. Ambas as partes encontram-se localizadas à esquerda do plano mediano. O cólon ascendente dispõe-se de forma bastante particular, ocorrendo a presença de uma alça dupla que realiza um “looping” junto ao fígado. Uma característica relevante foi evidenciada ao comparar-se o reto de machos e fêmeas, onde nos machos o comprimento é maior. De posse dos resultados concluímos que apesar da chinchila ser um roedor, há características próprias da espécie e também outras que assemelham-se aos lagomorfos, constituindo uma relação entre essas ordens. (AU)

The aim of this study was to describe the morphological and topographic aspects of the chinchillas digestive apparatus (DA) through dissection of 10 animals. We collected the DA segments and made the volumetric analysis of cavitary organs through injection of saline solution at 60°C, and measuring of the tubular organs. The parenchymal organs were weighed. During analysis of the position of organs, evisceration and measuring, was observed that the oral cavity is typical of rodents, the salivary glands are similar to lagomorphs and organs as esophagus, stomach, duodenum, transversal colon, liver, pancreas and spleen were disposed in similar way to described to other species. On the other hand, jejunum and descending colon were found to be very long and disposed on a wavy way, hanging from the roof of the abdominal cavity. The ileum was found to be similar to other species, but its disposition topographic is from the right to the left, heading to cecum, which is made of two well developed distinct portions. Both portions are located to the left of the median plane. Ascending colon is disposed in a very particular way, in which we observe a double loop which makes a circle at the liver. A relevant characteristic was in evidence comparing the rectum of males and females: males' is longer. Based on these data we conclude that despite the fact that chinchillas are rodents, they have particular characteristics of their own, and other characteristics similar to lagomorphs, being then a connection between these orders. (AU)