-transparent.png){kind=logo}
This study describes the localization of alpha-parvalbumin, in undecalcified tibial epiphyseal cartilage and bone of growing rats by immunocytochemistry in the light microscope, and of parvalbumin mRNA by in situ hybridization. They were compared to the distribution of the calbindin-D9K and its mRNA in rat epiphyseal cartilage. All the chondrocytes of the epiphyseal cartilage were parvalbumin-immunopositive, but there was no parvalbumin immunoreactivity in the uncalcified or calcified extracellular cartilage matrix. The intensity of the immunostaining increased from the resting and proliferative to the mature and hypertrophic chondrocytes, with the greatest intensity in the terminal hypertrophic chondrocytes in the calcifying zone. The parvalbumin immunostaining was located in the cytoplasm, but no immunoreactivity was detected in any chondrocyte processes. The parvalbumin mRNA distribution and levels, as revealed by in situ hybridization, exactly mirrored those of the parvalbumin protein. In contrast to parvalbumin, calbindin-D9K and its mRNA appeared in mature chondrocytes and decreased in hypertrophic up to calcifying chondrocytes. Calbindin-D9K was located in the cytoplasm and all along the cell processes. In bone, the osteoblasts and the osteocytes of trabecular and compact cortical bones were immunoreactive for parvalbumin and contained parvalbumin mRNA. Parvalbumin lay in their cytoplasm, but there was no parvalbumin immunostaining in the extracellular uncalcified or mineralized bone matrix. The long processes of osteocytes, in compact bone only, were parvalbumin immunoreactive. Osteoclasts contained cytoplasmic parvalbumin immunoreactivity. Thus, the pattern of immunoreactive parvalbumin distribution indicates that the protein is not involved in the extracellular mineralization of cartilage and bone matrix. It appears to be associated with specific calcium-related intracellular functions in chondrocytes and in osteoblasts, osteocytes, and osteoclasts. As the highest cytoplasmic concentration of parvalbumin is in the terminal hypertrophic chondrocytes, parvalbumin could act as a calcium buffer to delay the death of chondrocytes. In compact bone, parvalbumin could also have a role throughout the osteocyte processes in regulating the fluxes of calcium ions for mineral homeostatis.
R Toury, and
F Belqasmi, and
M Hauchecorne, and
D Leguellec, and
C W Heizmann, and
N Balmain
July 1997,
Histochemistry and cell biology,
R Toury, and
F Belqasmi, and
M Hauchecorne, and
D Leguellec, and
C W Heizmann, and
N Balmain
July 1967,
The Journal of cell biology,
R Toury, and
F Belqasmi, and
M Hauchecorne, and
D Leguellec, and
C W Heizmann, and
N Balmain
March 1997,
Cellular and molecular biology (Noisy-le-Grand, France),
R Toury, and
F Belqasmi, and
M Hauchecorne, and
D Leguellec, and
C W Heizmann, and
N Balmain
June 1999,
Bone,
R Toury, and
F Belqasmi, and
M Hauchecorne, and
D Leguellec, and
C W Heizmann, and
N Balmain
October 1996,
Nephrology, dialysis, transplantation : official publication of the European Dialysis and Transplant Association - European Renal Association,
R Toury, and
F Belqasmi, and
M Hauchecorne, and
D Leguellec, and
C W Heizmann, and
N Balmain
November 1970,
The American journal of pathology,
R Toury, and
F Belqasmi, and
M Hauchecorne, and
D Leguellec, and
C W Heizmann, and
N Balmain
February 1985,
American journal of veterinary research,
R Toury, and
F Belqasmi, and
M Hauchecorne, and
D Leguellec, and
C W Heizmann, and
N Balmain
January 1968,
Surgical forum,
R Toury, and
F Belqasmi, and
M Hauchecorne, and
D Leguellec, and
C W Heizmann, and
N Balmain
January 1998,
Anticancer research,
R Toury, and
F Belqasmi, and
M Hauchecorne, and
D Leguellec, and
C W Heizmann, and
N Balmain
January 1957,
Acta pathologica et microbiologica Scandinavica,
