The renal cortical lymphatic system in the rat, hamster, and rabbit

Abstract

Rat, hamster, and rabbit renal cortical lymphatics were examined by light and electron microscopy. Rat and hamster kidneys possessed both intra- and interlobular lymphatics that were structurally similar at the light microscopic level. Ultrastructural examination of the hamster lymphatic endothelium, however, revealed an unusual arrangement of cytoplasmic extensions not seen in the other two species. The intralobular lymphatics were related primarily to tubules, afferent arterioles, and renal corpuscles and were consistent with lymph formation from both plasma filtrate and tubular reabsorbate. Interlobular lymphatics were seen in connective tissue associated with the interlobular blood vessels. Rabbit cortex contained only interlobular lymphatics. Cross-sectional area, maximum diameter, volume density, and profile density were determined by stereological measurements using a computer-based image analyzer. The morphological data from the rat were used, in combination with published values for lymph flow, to calculate the rate of lymph formation per unit area of endothelium in lymphatics of the renal cortex. Among kidneys fixed by retrograde perfusion, the cortical lymphatic system was most extensive in maximum diameter, volume density, and profile density. It was smallest in the rabbit and intermediate in the rat. Lower volume and profile density were found for rat kidneys fixed by the dripping technique. It was concluded that: tubular reabsorbate probably contributes to renal lymph in the rat and hamster, but not in the rabbit; significant differences exist in the extent of the renal lymphatic systems among the three species, with the hamster kidney having the richest network and the rabbit the poorest; the method of fixation influences the measured size and density of renal cortical lymphatics; and the estimated rate of lymph formation in the kidney of the rat is roughly comparable to that in the dog.

Pattern and distribution of intrahepatic lymph vessels in the rat

“…Finally, based on the two methods of calculating the lymphatic surface area, the rate of lymph formation in the liver of the rat is approximately 0.06-0.08 pliminl cm2 of lym hatic endothelium. In comparison, rates of 1 canine kidney and 0.3-0.4 pl/ min/cm2 for vessels of the rat kidney (Niiro et al, 1986). In contrast to Comparini's report (1969) of "central lymphatics" next to sublobular (intercalated) veins, such vessels were not found in the present study.…”

Lymphatic Vessels in Pancreatic Islets Implanted Under the Renal Capsule of Rats

“…Interstitially injected Evans Blue was drained through progressively larger lymph vessels, which finally emptied into the kidney parenchyma, presumably into renal intra‐lobular lymph vessels, which then exit from the kidney through hilar lymphatics (20,21). In confirmation of this we could observe dye in regional lymph nodes close to the celiac plexus in some animals.…”

Renal Lymphatics: Anatomy, Physiology, and Clinical Implications

“…Anatomy between different species is very similar with a few exceptions; rabbit kidneys appear to lack intralobular lymphatics (O’Morchoe and O’Morchoe, 1988) and the sheep kidney lacks a capsular system (McIntosh and Morris, 1971) (Table 1). The species with the least extensive intra-cortical lymphatics (the rabbit) has the lowest urine concentrating ability and the species with the most extensive system (the golden hamster) has the highest concentrating ability (Niiro et al, 1986).…”