Effect of transforming growth factor beta1 on chondrogenic differentiation of cultured equine mesenchymal stem cells.
OBJECTIVE
To determine the morphologic and phenotypic effects of transforming growth factor beta1 (TGFbeta1) on cultured equine mesenchymal stem cells (MSC) and articular chondrocytes.


METHODS
Bone marrow aspirates and articular cartilage samples from a 2-year-old and two 8-month-old horses.


METHODS
After initial isolation and culture, MSC and chondrocytes were cultured in Ham's F-12 medium supplemented with TGF-beta1 at a concentration of 0, 1, 5, or 10 ng/ml. Medium was exchanged on day 2, and cells were harvested on day 4. Medium was assayed for proteoglycan (PG) content. Total RNA was isolated from cell cultures, and expression of aggrecan, decrin, collagen type-I, and collagen type-II mRNA was assessed by means of Northern blot analyses. Cell cultures were stained with H&E or toluidine blue and examined histologically. Additional cultures were examined after immunohistochemical staining for type-I and -II collagen.


RESULTS
MSC cultures exposed to TGF-beta1 had an increased cellular density with cell layering and nodule formation that was most pronounced in cultures treated with 5 ng of TGF-beta1/ml. Expression of collagen type-II mRNA in MSC cultures exposed to 5 ng of TGF-beta1/ml was 1.7 times expression in control cultures, and expression of collagen type-I mRNA was 2.8 times expression in control cultures. Treatment of MSC with TGF-beta1 led to dose-related increases in area and intensity of type-II collagen immunoreaction.


CONCLUSIONS
Results suggest that TGF-beta1 enhances chondrogenic differentiation of bone marrow-derived MSC in a dose-dependent manner.
Worster
A A
AA
Comparative Orthopaedics Laboratory, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
Nixon
A J
AJ
Brower-Toland
B D
BD
Williams
J
J
D000818:Animals; D015152:Blotting, Northern / Q000662:veterinary; D001854:Bone Marrow Cells / Q000166:cytology; D002358:Cartilage, Articular / Q000166:cytology / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D006736:Horses; D017403:In Situ Hybridization; D010641:Phenotype; D013234:Stem Cells / Q000187:drug effects*; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
D016212:Transforming Growth Factor beta