Postnatal development of the canine kidney: Quantitative and qualitative morphology

Abstract

The normal postnatal development of the canine kidney was investigated utilizing qualitative and quantitative histologic methods. Kidneys were examined at 2, 4, 8, 14, 22, 70, and 200 days of age. A subcapsular nephrogenic zone was present in the kidneys until approximately eight days of age. This zone contained tissues which interacted to produce new nephrons and interstitial tissues. Several developmental stages of forming nephrons were identified in this zone. Beneath the nephrogenic zone, renal corpuscles of increasing maturity were located at successively deeper cortical levels. The total number of nephrons was estimated to be 445,000 per kidney. This number did not vary significantly during growth. The corpuscular volume per nephron increased 249% from 14 to 200 days of age. During the same period there was a 303% increase in the tubular volume per nephron. Although the developing kidney differed anatomically from the adult kidney, the individual nephrons maintained volumetric corpuscular-tubular balance during growth.

Patlak plot analysis CT‐GFR for the determination of renal function: comparison of normal dogs with autologous kidney transplant dogs

“…Baseline normal renal volume was greater in the group 2 dogs, measured by water displacement, than in the group 1 dogs measured by CT. Because of this apparent significant difference at baseline between CT and water displacement measurement techniques, particularly given that group 2 dogs weighed less but had apparently larger kidneys than group 1 dogs, no further statistical comparison was made between baseline (water displacement volume) and at day 6 (CT volume) in group 2 dogs. Normal renal volume in young adult Beagle dogs weighing 9.78 kg is 26.8 ml, as measured by water displacement following removal of perirenal fat and the renal pedicle, similar to what we obtained via CT (29). The larger renal volume measured in group 2 dogs is typical after allograft with a 24 h cold preservation period.…”

Aging in the Canine Kidney

“…Nephron number in Beagles was estimated to range from 445 000 to 589 000 per kidney 20,30 ; however, other breeds have not been reported. A wider range of nephron number would not be surprising, given the marked variation in other breedassociated phenotypes.…”

“…Although it is not uncommon to detect fetal or immature glomeruli until 21 days of age, these should dwindle in number after that time. 20 Notably, infection, stress, or toxin exposure during this period of postnatal development might interrupt the maturation process and lead to increased frequency of fetal glomeruli. Identifying a few scattered fetal glomeruli in normal canine renal specimens is possible, with smaller dogs being more commonly affected than larger dogs (personal observation).…”

Morphometrical Studies on Perinatal Development of Glomerular Components in Rat

“…The development of kidney during both the prenatal and postnatal periods has been studied in man [4], dogs [5], rabbits [6], mice [7], and rats [8,9]. As to the function of rat fetal kidney, Schaeverbeke and Cheignon [10] reported that glomerular filtration func tions from fetal day 18, whereas Bakala et al [11] reported that effective filtration does not start until fetal day 20.…”