Stereological and serial section analysis of chondrocytic enlargement in the proximal tibial growth plate of the rat

Abstract

In this study we demonstrated that chondrocytic enlargement starts immediately following cell division in the proliferative zone, and that chondrocytic enlargement consists of two morphologically distinguishable phases. The transition point between the first and the second phase of chondrocytic enlargement corresponded with the junction between the proliferative zone and the maturation zone.

Three‐dimensional in situ zonal morphology of viable growth plate chondrocytes: A confocal microscopy study

“…Observed differences in chondrocyte size are consistent with previous studies on chondrocyte morphology using conventional histology and stereological methods. 6,7,19 In a study carried out by Breur et al 8 the mean chondrocyte volume was characterized in rat proximal tibial growth plates divided into eight horizontal strata of equal heights. Estimated mean chondrocyte volume in the first six strata indicates similar magnitude to those measured for reserve and proliferative chondrocytes in the present study.…”

“…5 Chondrocytes located at epiphyseal end of the proliferative zone divide rapidly while chondrocytes located at metaphyseal end of the proliferative columns start to increase in size towards the hypertrophic zone. [6][7][8][9][10][11] In the hypertrophic zone, cell division stops and terminal differentiation associated with a large increase in cell volume begins. 5 The mechanisms by which growth plate chondrocytes modulate longitudinal bone growth are still not well understood.…”

“…3,6,19 The differential growth of various bones also appears to be related to size differences in hypertrophic chondrocytes. 6,8,9,13,19 In growth plates undergoing rapid growth, such as in the femur, chondrocytes hypertrophy to a greater extent than do chondrocytes in growth plates from less rapidly growing bones, such as in the radius. 17,18 In an in vivo study on rat caudal growth plates, the degree of mechanically modulated growth was found to correlate with hypertrophic chondrocytes enlargement in the direction of growth.…”

“…15 Conventional histology and stereological techniques combined with chemical fixation have been used to characterize two-and three-dimensional growth plate morphometric parameters in different animal species both at tissue and cell levels. 2,3,6,8,9,19,23 In studies on the rat model at prepubertal, growth spurt, and mature developmental stages, it was demonstrated that, from the proliferative zone to the hypertrophic zone, chondrocyte volume enlarges up to 10-fold while chondrocyte height increases up to 5-fold. [6][7][8] In a study by Buckwalter et al 9 on 35-day-old mice model, a fivetime increase in chondrocyte volume was reported from the resting zone to the late hypertrophic zone.…”

Continuous Activation of Gαq in Osteoblasts Results in Osteopenia through Impaired Osteoblast Differentiation

“…Classical teaching was that there was a linear relationship between the volume of hypertrophic chondrocytes and the rate of longitudinal bone growth and that limb-shortening defects were because of defects in the growth plate (27)(28)(29)(30). Studies from Karsenty and co-workers (31) have challenged this paradigm.…”