Use of adverse conditions to stimulate a cellular stress response by equine articular chondrocytes.
OBJECTIVE
To determine the response of equine articular cartilage cells to heat and calcium stresses.


METHODS
Analysis of newly synthesized, [35S]methionine-labeled proteins after treatment of isolated primary equine chondrocytes.


METHODS
Primary cultures of equine articular chondrocytes were incubated at temperatures ranging from 37 to 42 C for heat stress experiments or incubated in the presence or absence of the intracellular calcium pump inhibitor, thapsigargin, for calcium stress experiments. Patterns of new protein synthesis were determined by incubating with [35S]methionine followed by separation of proteins by use of one- or two-dimensional gel electrophoresis and visualization of labeled proteins by use of fluorography.


RESULTS
Equine chondrocytes cultured at temperature of 42 C had increased synthesis of specific proteins, compared with the profile of protein synthesis in control chondrocytes cultured at 37 C. These changes were characteristic of the heat shock stress response described in a number of other mammalian cell-types. Equine chondrocytes cultured in the presence of thapsigargin also had increased synthesis of specific proteins. Two-dimensional gel electrophoresis of these newly synthesized proteins revealed the changes to be consistent with the induction of the glucose-regulated protein family of stress proteins.


CONCLUSIONS
Changes in the pattern of new protein synthesis can be induced in differentiated equine articular chondrocytes by heat shock or calcium stress. These responses are characteristic of a widely described mammalian stress response that has been postulated to be involved in cellular protective mechanisms. The ability of equine chondrocytes to mount a robust stress response may be important in the processes of tissue damage and recovery in articular joints of horses.
Benton
H P
HP
Department of Anatomy, Physiology, and Cell Biology, School of Veterinary Medicine, University of California, Davis 95616, USA.
Cheng
T C
TC
MacDonald
M H
MH
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors; D002358:Cartilage, Articular / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D015180:Electrophoresis, Gel, Two-Dimensional / Q000379:methods / Q000662:veterinary; D004591:Electrophoresis, Polyacrylamide Gel; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D006360:Heat-Shock Proteins / Q000378:metabolism; D006736:Horses / Q000378:metabolism / Q000502:physiology*; D006358:Hot Temperature / Q000009:adverse effects*; D008297:Male; D008715:Methionine / Q000378:metabolism; D013462:Sulfur Radioisotopes; D013729:Terpenes / Q000494:pharmacology; D019284:Thapsigargin
D004791:Enzyme Inhibitors; D006360:Heat-Shock Proteins; D013462:Sulfur Radioisotopes; D013729:Terpenes; D019284:Thapsigargin; D008715:Methionine; D000252:Calcium-Transporting ATPases; D002118:Calcium