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Int J Clin Exp Pathol 1(5):426-434;2008

Original Article
In Vitro Healing of Avascular Meniscal Injuries with Fresh and Frozen Plugs Treated with
TGF-β1 and IGF-1 in Sheep

Iñigo Izal, Purificación Ripalda, Carlos A Acosta and Francisco Forriol

Orthopaedic Research Laboratory, University of Navarra, Pamplona, Spain and Research Area, Fremap, Majadahonda, Spain.

Received 10 Oct 2007; Accepted with revision 16 Dec 2007; Available online 1 January 2008

Abstract: We studied the effect of freezing and inserting meniscal plugs in lesions generated in the avascular area of sheep menisci
maintained in vitro, and whether the healing process can be improved by adding growth factors TGF-β1 and IGF-1. Thirty six menisci obtained
from healthy 3 months-old sheep were cultured in 6 well plates and holes were perforated in the avascular area. Meniscal plugs, either fresh or
frozen at -20ºC for 1 month, were used to fill in the lesions, and then cultured in the presence or absence of TGF-β1 or IGF-1 for 8 weeks.
Samples stained with Massons trichrome were analyzed to evaluate the attachment of the plug and the cell density of the tissue. BrdU
immunohistochemistry was performed to identify the proliferation of meniscal cells. Both growth factors improved considerably the cell density
of implanted plugs. TGF-β1 increased significantly the attachment of both fresh and frozen plugs, but it had no effect on meniscal cell
proliferation. In contrast, IGF-1 had no effect on the attachment, but did increase significantly the number of proliferating cells in the surface of
the host meniscus and the inserted plug. In conclusion, frozen plugs can survive if treated with either TGF-β1 or IGF-1. The combination of TGF-
β1 and IGF-1 could aid in the repairing of the avascular meniscal injuries, as they are capable of promoting the attachment of tissue, and
increasing the proliferation of meniscal cells. (IJCEP710006).

Key Words: TGF-β1, IGF1, meniscus, avascular injury, sheep, tissue engineering

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Address all correspondence to: Francisco Forriol, MD, PhD, Research Area - Hospital FREMAP, Ctra Pozuelo 61, 28220 Majadahonda, Madrid,
Spain. Phone: +34 91 626 5811; E-mail: