Absolute volumes of glomerular cells and glomerular compartments in the normal rat kidney

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• AS_13_n1_63_SOO (2.1M)

Abstract

Alterations in the size of renal glomeruli, in the number and size of glomerular cells, and in the size of the major glomerular compartments (matrix, capillary lumina, urinary space) occur in various renal disorders. We have previously used unbiased stereological methods to estimate glomerular size and the total number of glomeruli and individual glomerular cell types in the kidneys of seven normal female Sprague-Dawley rats. In the present study we combined the earlier data with volume density estimates obtained using traditional point counting methods at the electron microscopic level to estimate the average volumes of individual glomerular cell types and of the major glomerular compartments. Surface density estimates of the plasma membrane of glomerular epithelial cells (GECs) were used to estimate average GEC surface area. To estimate volume and surface densities, one thin section from each of six randomly selected renal corpuscles was analyzed from each rat. Each section provided approximately 20 electron micrographs (final magnification x23,500). Estimates were: renal corpuscle volume 8.588 ± 1.084 µm³ x 10⁵ (mean ± SD), GEC volume 584 ± 105 µm³, endothelial cell volume 151 ± 39 µm³, mesangial cell volume 149 ± 31 µm³, parietal epithelial cell volume 182 ± 49 µm³, matrix volume 3.841 ± 0.604 µm³ x 10⁴, capillary lumina volume 2.664 ± 0.378 µm³ x 10⁵, urinary space volume 3.467 ± 509 µm³ x 10⁵, and GEC surface area 5.211 ± 0.967 µm² x 10³. This study has provided baseline data for the volumes of individual glomerular cells and the major glomerular compartments. This data will be useful in identifying changes in glomerular dimensions in disease.

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About: Mary C. Soosaipillai

About: John F. Bertram

About: Graeme B. Ryan