Stereological study of the kidney during prenatal development in sheep

Abstract

The development of metanephros is a complex and gradual process. The number, size and distribution of nephrons provide important information about the organization of the kidney. Stereology is the current gold‐standard technique for the morphometrical evaluation of kidney structures. This study describes morphometric features of the kidney development in sheep using design‐based stereological techniques aimed to introduce the sheep as a translational model in human nephrogenesis. Left kidneys of 16 sheep fetuses in four groups at 9–11, 12–14, 15–17, and 18–20 weeks of gestation were used in the present study. Systematic uniform random sections were obtained. The kidney volume, volume fraction of nephrogenic zone, cortex and medulla, and glomerular volume were estimated using point counting and Cavalieri's estimator. The total glomerular number was estimated using a physical disector/fractionator technique. The kidney and its compartments presented gradual changes with aging, with differences found in the last fetal ages. The kidney volume increased from 0.94 ± 0.22 cm3 to 8.6 ± 0.88 cm3 during development. The volume of cortex increased from 406 ± 85 mm3 to 5,151 ± 309 mm3 and the volume of medulla showed increase from 301 ± 91 mm3 to 3,426 ± 599 mm3. The total glomerular volume increased from 13.8 ± 1.6 mm3 to 235 ± 44 mm3. The total glomerular number increased from 4,683 ± 757 to 639 × 103 ± 11.6 × 103. Our data might contribute to the knowledge of embryological urology and promote future experimental investigations in this field.

Three‐dimensional morphometry of kidney in New Zealand rabbit using unbiased design‐based stereology

“…The numerosity of the glomerular count among different species can be due to the difference in the weight of their kidneys which is correlated with the number of glomeruli as has also been demonstrated in humans (Nyengaard & Bendtsen, 1992). It coincided with observations made for the glomerular number in the baboon (Gubhaju & Black, 2005) and sheep (Sadeghinezhad & Nyengaard, 2021) which was related to kidney volume in different gestational ages.…”

“…However, the mean glomerular volume varies between different species, which has already been found to be related to kidney weight (Nyengaard & Bendtsen, 1992). In agreement with this, an investigation on the quantitative stereology of kidneys during development in sheep also showed a significant correlation between the total volume of glomeruli and kidney volume (Sadeghinezhad & Nyengaard, 2021). Based on this, the total glomerular volume was calculated 67 mm 3 and mean glomerular volume was reported as 4.7 mm 3 Â 10 À4 in young rabbits (Maduwegedera et al, 2007), which is less compared to the data obtained in this study in adult rabbits.…”

Three-dimensional reconstruction of fetal rhesus macaque kidneys at single-cell resolution reveals complex inter-relation of structures

“…(Fig. 3B) As expected 34 , developing corpuscles displayed much smaller volumes than mature glomeruli. It appeared that the distribution of mature glomerular tufts was relatively narrow with a mean volume of around 1.75x10 5 μm 3 .…”

“…Glomeruli are a widely accepted marker of renal health 2,33 and have been extensively investigated. [9][10][11]34 Aside from the number and size of glomeruli on a whole organ level, which is already challenging information to extract using most organ mapping techniques, we used CODA to assess parameters that are difficult to quantify at scale using conventional techniques. These parameters included the volume occupied by the Bowman's capsule and the urinary space in each glomerulus, as well as the absolute number of cells and the cell packing density of glomeruli across different regions of the kidney.…”