Hp. Benton et al., USE OF ADVERSE CONDITIONS TO STIMULATE A CELLULAR STRESS-RESPONSE BY EQUINE ARTICULAR CHONDROCYTES, American journal of veterinary research, 57(6), 1996, pp. 860-865
Objective - To determine the response of equine articular cartilage ce
lls to heat and calcium stresses. Design - Analysis of newly synthesiz
ed, [S-35]methionine-labeled proteins after treatment of isolated prim
ary equine chondrocytes. Procedure - Primary cultures of equine articu
lar chondrocytes were incubated at temperatures ranging from 37 to 42
C for hear 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 [S-35]methionine followed by separation oi protein
s by use of one- or two-dimensional gel electrophoresis and visualizat
ion of labeled proteins by use of fluorography. Results - Equine chond
rocytes cultured at temperature of 42 C had increased synthesis of spe
cific protein, compared with the profile of protein synthesis in contr
ol chondrocytes cultured at 37 C. These changes were characteristic of
the heat shock stress response described in a number of other mammali
an cell-types. Equine chondrocytes cultured in the presence of thapsig
argin also had increased synthesis of specific proteins. Two-dimension
al gel electrophoresis of these newly synthesized proteins revealed th
e changes to be consistent with the induction oi the glucose-regulated
protein family oi stress proteins. Conclusions - Changes in the patte
rn of new protein synthesis can be induced in differentiated equine ar
ticular chondrocytes by heal shock or calcium stress. These responses
are characteristic of a widely described mammalian stress response tha
t 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 ar
ticular joints of horses.