The fate and role of bone graft-derived cells after autologous tendon and bone transplantation into the bone tunnel
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Grafting bone between the tendon graft and the bone tunnel in anterior cruciate ligament reconstruction increases the mechanical strength of the tendon graft. However, the biological role of the bone graft is unclear. The purpose of this research was to elucidate the role of bone graft cells after autologous tendon graft into the bone tunnel with an autologous bone graft in green fluorescent protein (GFP) transgenic rats.
The Achilles tendons of Sprague-Dawley (SD) wild-type rats and bone of GFP rats were harvested and transplanted into bone tunnels drilled in the femurs at the knees of SD rats. The femurs were harvested at 1, 2, and 4 weeks after transplantation and histologically investigated using hematoxylin and eosin staining and immunostaining of heat shock protein 47 (HSP47), macrophages, and type I and type III collagens. Biomechanical tests were performed on the tendon graft 2 and 4 weeks after transplantation to evaluate the ultimate force to failure.
A small number of GFP-positive cells was seen in the tendon graft 2 weeks after transplantation. The cell count in the tendon graft was increased at 4 weeks after transplantation. HSP47-positive cells and macrophage-stained cells present in the tendon graft corresponded with the GFP-positive cells. By 2 weeks after transplantation, the relative areas of immunostained type I and III collagens in the tendon graft had declined significantly in the bone graft group compared to the control. The ultimate failure load in the bone graft group was higher than that in the control group at both 2 and 4 weeks after transplantation.
This research showed that, within 4 weeks of transplantation, bone graft cells migrate to the tendon graft, where they differentiate into cells involved in collagen production and macrophages. Bone graft cells may contribute to the early stage remodeling of tendon grafts.
Conflict of interest
The authors declare that they have no conflict of interest.
- 4.Yasuda K, Tanabe Y, Kondo E, Kitamura N, Tohyama H. Anatomic double-bundle anterior cruciate ligament reconstruction. Arthroscopy. 2010;26:21–34.Google Scholar
- 7.Shino K, Kawasaki T, Hirose H, Gotoh I, Inoue M, Ono K. Replacement of the anterior cruciate ligament by an allogeneic tendon graft. An experimental study in the dog. J Bone Joint Surg. 1984;66:672–81.Google Scholar
- 14.Tachiiri H, Morihara T, Iwata Y, Yoshida A, Kajikawa Y, Kida Y, Matsuda K, Fujiwara H, Kurokawa M, Kawata M, Kubo T. Characteristics of donor and host cells in the early remodeling process after transplant of Achilles tendon with and without live cells for the treatment of rotator cuff defect—what is the ideal graft for the treatment of massive rotator cuff defects? J Should Elbow Surg. 2010;19:891–8.CrossRefGoogle Scholar
- 16.Arai Y, Hara K, Takahashi T, Urade H, Minami G, Takamiya H, Kubo T. Evaluation of the vascular status of autogenous hamstring tendon grafts after anterior cruciate ligament reconstruction in humans using magnetic resonance angiography. Knee Surg Sports Traumatol Arthrosc. 2008;16:342–7.PubMedCrossRefGoogle Scholar
- 17.Yukata K, Matsui Y, Shukunami C, Takimoto A, Hirohashi N, Ohtani O, Kimura T, Hiraki Y, Yasui N. Differential expression of tenomodulin and chondromodulin-1 at the insertion site of the tendon reflects a phenotypic transition of the resident cells. Tissue Cell. 2010;42(2):116–20.PubMedCrossRefGoogle Scholar