In vitro culture decreases the expression of TGF(beta), Hsp47 and type I procollagen and increases the expression of CTGF in avian tendon explants.
Weight-bearing tendons in many species, including humans, chickens and horses, are prone to failure, in many cases without a discernible cause. The normal function of the tendon depends on the proper assembly of fibrils of type I collagen, the main structural component of the tendon. We studied the effect of in vitro culture, temperature (37 degrees C vs. 43 degrees C) and wounding on the expression of mRNAs for several collagen regulators, transforming growth factor beta (TGF(beta)), heat shock protein 47 (Hsp47) and connective tissue growth factor (CTGF), in chicken embryonic gastrocnemius tendon explants. The expression of mRNAs for TGF(beta) and Hsp47, a chaperone of collagen assembly, remained strong during the first day of in vitro culture, but then it decreased, slightly more at higher temperature. Additional injury in selected tendons had no significant effect on the levels of TGF(beta) and Hsp47 mRNAs. Likewise, the level of immunostained type I procollagen also decreased with the length of culture. The expression of CTGF gradually increased from 0 at the time of tendon removal with the duration of culture to strong after three days of culture when the expression of TGF(beta) and Hsp47 was low. We conclude that in vitro culture over the period of several days rather than an increase in temperature or additional wounding decreases the expression of TGF(beta), Hsp47 and type I procollagen and increases the expression of CTGF.
Halper
J
J
The Soft Tissue Center, Department of Pathology, The University of Georgia, Athens, GA 30602, USA. jhalper@vet.uga.edu
Griffin
A
A
Hu
W
W
Jung
C
C
Zhang
J
J
Pan
H
H
Kisaalita
W S
WS
Foutz
T L
TL
Frazier
K S
KS
D000818:Animals; D002478:Cells, Cultured; D002642:Chick Embryo; D024042:Collagen Type I / Q000096:biosynthesis* / Q000235:genetics* / Q000378:metabolism*; D055513:Connective Tissue Growth Factor; D015536:Down-Regulation / Q000502:physiology; D006360:Heat-Shock Proteins / Q000235:genetics*; D017874:Immediate-Early Proteins / Q000235:genetics*; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism; D012038:Regeneration / Q000502:physiology; D015843:Serpins / Q000235:genetics*; D013696:Temperature; D013708:Tendon Injuries / Q000378:metabolism / Q000503:physiopathology; D013710:Tendons / Q000378:metabolism*; D013997:Time Factors; D016212:Transforming Growth Factor beta / Q000235:genetics*; D015854:Up-Regulation / Q000502:physiology; D014945:Wound Healing / Q000502:physiology
C526317:CCN2 protein, human; D024042:Collagen Type I; D006360:Heat-Shock Proteins; D017874:Immediate-Early Proteins; D036341:Intercellular Signaling Peptides and Proteins; D012333:RNA, Messenger; D015843:Serpins; D016212:Transforming Growth Factor beta; D055513:Connective Tissue Growth Factor