title: Effect of transforming growth factor-beta1 on morphological characteristics relating to migration and differentiation of rabbit chondrocytes cultured in collagen gels.
abstract: The influence of transforming growth factor-beta1 (TGFbeta1) on the behavior of rabbit chondrocytes embedded in collagen gels was examined in terms of cell migration and consequent architecture of cell aggregation. In a low-seeding density culture (X(0)=2.0 x 10(5) cells/cm(3)) TGFbeta1 (0-10.0 ng/ml) was added and observed during a 14-d culture period. Stereoscopic observation was performed on 5 d employing the morphology-related parameter of sphericity (S(c)) for individual cells in the gels. The frequency of migrating cells with S(c) less than 0.95 increased in a dose-dependent manner in response to TGFbeta1. Moreover, the frequency of migrating cells in the culture with 10.0 ng/ml TGFbeta1 was 0.32, two times higher than that in the reference culture without TGFbeta1, while the frequency of dividing cells in the same culture was less than half of that in the reference culture. The histological observation of cultured gels on 14 d revealed that the starburst and loose aggregates with the spindle-shaped cells emerged in the TGFbeta1-free culture, accompanying the poor production of collagen type II by the cells. On the other hand, the spherical-shaped cells were observed in the starburst aggregates with rich excretion of collagen type II in the culture with 5.0 ng/ml TGFbeta1. Moreover, the mRNA levels of differentiation-marker genes (collagen types I and II) were regulated in accordance with the morphological analyses concerning the cell migration and aggregation in the cultures with and without TGFbeta1. From these results, it was concluded that TGFbeta1 had a culture time-dependent effect on the morphological characteristics relating to the migration and differentiation of the chondrocytes in the collagen gel-embedded cultures seeded at low density, that is, the growth factor promotes cell migration with deteriorated proliferation in the early culture phase, and accelerates the transformation of spindle-shaped cells to spherical-shaped ones in the prolonged culture.
authors.affiliation: Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama-cho, Toyonaka, Osaka 560-8531, Japan.
authors.forename: Ali Baradar
authors.initials: AB
authors.lastname: Khoshfetrat
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kino-oka
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Takezawa
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Sato
authors.forename: Takeyuki
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Katsura
authors.initials: K
authors.lastname: Sugawara
authors.forename: Masahito
authors.initials: M
authors.lastname: Taya
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects*; D002465:Cell Movement / Q000187:drug effects*; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology / Q000187:drug effects*; D003094:Collagen; D003470:Culture Media; D012333:RNA, Messenger / Q000235:genetics; D011817:Rabbits; D020133:Reverse Transcriptase Polymerase Chain Reaction; D053773:Transforming Growth Factor beta1 / Q000235:genetics / Q000494:pharmacology*
chemical_list: D003470:Culture Media; D012333:RNA, Messenger; D053773:Transforming Growth Factor beta1; D003094:Collagen