Innovative Three-Dimensional Microscopic Analysis of Uremic Growth Plate Discloses Alterations in the Process of Chondrocyte Hypertrophy: Effects of Growth Hormone Treatment

Abstract

Chronic kidney disease (CKD) alters the morphology and function of the growth plate (GP) of long bones by disturbing chondrocyte maturation. GP chondrocytes were analyzed in growth-retarded young rats with CKD induced by adenine intake (AD), control rats fed ad libitum (C) or pair-fed with the AD group (PF), and CKD rats treated with growth hormone (ADGH). In order to study the alterations in the process of GP maturation, we applied a procedure recently described by our group to obtain high-quality three-dimensional images of whole chondrocytes that can be used to analyze quantitative parameters like cytoplasm density, cell volume, and shape. The final chondrocyte volume was found to be decreased in AD rats, but GH treatment was able to normalize it. The pattern of variation in the cell cytoplasm density suggests that uremia could be causing a delay to the beginning of the chondrocyte hypertrophy process. Growth hormone treatment appears to be able to compensate for this disturbance by triggering an early chondrocyte enlargement that may be mediated by Nkcc1 action, an important membrane cotransporter in the GP chondrocyte enlargement.

Systemic Jak1 activation causes extrarenal calcitriol production and skeletal alterations provoking stunted growth

“…35 Alcian blue-safranin staining determined individual and overall growth plate heights, height of proliferative (PZ) and hypertrophic zone (HZ), and height of the last three chondrocytes. Collagen X, BrdU, and IGF1 were detected by immunodetection as described previously, 36,37 using the antibodies listed in Table S2. Phospho-Stat3 was detected in femurs by immunohistochemistry, using 5 minutes Trypsin 0.2% at 37°C followed by 35 minutes EDTA 0.25 M pH 8 at 60°C for antigen retrieval.…”