Renal Microvasculature in Lylei’s flying fox (Pteropus lylei).

Objective: The purpose of this study was to elucidate the renal microvasculature of Lylei’s flying fox. Methods: The kidneys of twelve adult Lylei’s flying foxes of both sexes were processed by using vascular corrosion cast technique combined with SEM. Results: It was found that arcuate arteries at the corticomedullary junctions give off several interlobular arteries, which run perpendicularly into the renal cortex. The interlobular artery branches into two sets of vessels. Firstly, aglomerular arteriole divides into capsular and peritubular capillary plexus without forming glomeruli. Secondly, an afferent arteriole, a branch of the interlobular artery, breaks into the glomerular capillary plexus that gathers to form a single efferent arteriole. An efferent arteriole gives rise to a peritubular capillary plexus and vasa recta. A peritubular capillary forms a plexus among renal tubules. Vasa recta are straight vessels that run parallel to Henle’s loops and collecting ducts in the outer medulla. In addition, vasa recta form U- shaped loops in the inner medulla. Moreover, the fenestrated type of capillaries is observed. It was found that high numbers of the fenestration were seen in the glomerular capillary plexus and venous limbs of vasa recta in the outer medulla. In contrast, fewer knobs were presented in the loops of vasa recta in the inner medulla and peritubular capillary plexus. Both peritubular capillary plexus and vasa recta collect the blood into interlobular and arcuate veins. Conclusion: In this investigation, the aglomerular arteriole might be an important shunting of the blood, while this animal alters the position immediately. With the advantages of this technique, fenestrated capillaries are demonstrated which are related to the functions of each tubule. Moreover, the microvascular patterns of the kidney in this animal are similar to that in human. Therefore, it is a suitable model for renal microvascular investigation.

Adrenal microvasculature in the Lylei’s flying fox (Pteropus lylei).

Objective: The purpose of this study was to elucidate the microvasculature of the adrenal glands in the Lylei’s flying fox. Methods: The adrenal glands of the Lylei’s flying foxes were processed in the histological technique and vascular corrosion cast technique combined with the SEM. Results: Upon reaching the gland, the adrenal arteries divided into the cortical and medullary arteries. Firstly, the cortical arteries gave off subcapsular and true cortical capillary plexuses. Few loop cortical arteries were observed. At the corticomedullary junction, true cortical capillary plexus formed two groups, large peripheral venous radicles and sinusoidal medullary capillary plexus. Secondly, the medullary arteries supplied the inner cortex and medulla as true medullary capillary plexus. Therefore, the medullary capillary plexus composed of branches from cortical and medullary arteries. The medullary capillary plexus became a tributary of deep venous radicle. Both peripheral and deep venous radicles drained into the collecting, central, and adrenal veins, respectively. Furthermore, some medullary capillary plexus directly drained into the central vein without gathering into the collecting veins. Conclusions: Not only the microvascular connections in the cortex and medulla, but also several channels of the venous drainage were found in the glands of this animal model. Especially, the direct connections between the medullary capillary plexus and the central vein have not been demonstrated in other animal models. These direct routes may supply the sufficient blood to this organ, when the animal suddenly alters the positions. These findings also support the internal control of the cortex over the medulla. In addition, the pattern of adrenal microvascularization in this animal is similar to that in human. So that, this mammal is a suitable model for microvascular investigation.