Biologic behavior of an in vitro hydrated collagen gel-human tenocyte tendon model.
An in vitro human tenocyte-collagen gel model was developed to study tenocyte-mediated Type I collagen fibril reorganization, proliferation, and Type I collagen gene expression. Human tenocytes, obtained from extrasynovial forearm flexor tendons from children 5 to 10 years of age were cultured on plastic or in a cylinder of hydrated Type I collagen gel. Collagen solution was seeded with human tenocytes at 5 x 10(5) cells/mL and gelled in cylinder molds; gel cylinders without human tenocytes served as controls. Gel cylinders were pinned to troughs to create noncompliance. The gel cylinders were analyzed for collagen birefringence and cell shape at 7 and 21 days and for proliferation and gene expression for Type I collagen at 7 days. Under conditions of noncompliance, human tenocytes reoriented Type I collagen into longitudinal bundles resembling the parallel organization of collagen in native tendons. Tenocyte shape became fusiform between the collagen bundles which mimics the morphologic features of a tenocyte in vivo. The structural changes in the tenocytes and matrix are accompanied by downregulation of human tenocyte proliferation and Type I collagen gene expression. When released from the gel cylinder and grown again on plastic, human tenocytes resume proliferation and Type I collagen gene expression. The human tenocytes in this in vitro gel cylinder model system control fibril reorganization and proliferation, resembling their behavior during the development and repair of native tendons.
Lamberti
Paul M
PM
Department of Orthopaedic Surgery and Rehabilitation, Loyola University, Stritch School of Medicine, Maywood, IL 60153, USA.
Wezeman
Frederick H
FH
D015152:Blotting, Northern; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D024042:Collagen Type I / Q000378:metabolism*; D005782:Gels; D015870:Gene Expression; D006801:Humans; D013710:Tendons / Q000166:cytology*
D024042:Collagen Type I; D005782:Gels