Tenocyte response to cyclical strain and transforming growth factor beta is dependent upon age and site of origin

Article type: Research Article

Authors: Goodman, S.A. | May, S.A. | Heinegård, D. | Smith, R.K.W.^;

Affiliations: Department of Veterinary Clinical Sciences, Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Hertfordshire, UK AL9 7TA | Department of Cell and Molecular Biology, Section for Connective Tissue Biology, BMC, Plan C12, SE‐22184 Lund, Sweden

Note: [] Author for correspondence: Prof. R.K.W. Smith. Tel.: +44 01707 666272; Fax: +44 01707 660671; E‐mail: [email protected].

Abstract: The effect of strain and transforming growth factor beta on equine tendon fibroblasts (tenocytes) was assessed in vitro. Tenocytes were isolated from flexor and extensor tendons of horses from foetal to 10 years of age. These cells were cultured until confluent on collagen‐coated silicone dishes. Cyclic biaxial strain of 9±1% was applied at 0.5 Hz for 24 hours with or without added TGFβ1 or 3 (10 ng/ml). Proliferation and synthetic responses were dependent on the tendon of origin. Neither strain nor TGFβ caused flexor tenocytes to proliferate significantly, while strain alone did proliferate extensor tenocytes. TGFβ, with or without strain, increased the incorporation of [3H]‐proline and the production of types I and III collagen and COMP in both cell types, although the effect on COMP production was more marked in flexor tenocytes, perhaps reflecting the higher levels found in this tendon in vivo. Immature flexor tenocytes synthesised more collagen and COMP than those from mature animals, while age had little effect in extensor tenocytes. Our results suggest that tenocytes become differentiated at an early age and present tendon‐specific responses.

Journal: Biorheology, vol. 41, no. 5, pp. 613-628, 2004