Evaluation of the potential application of three different biomaterials combined with bone morphological proteins for enhancing tendon-bone integration.
BACKGROUND
Secure tendon-bone integration is crucial for successful anterior cruciate ligament (ACL) reconstruction. Previous studies have applied different types of biomaterial or biomaterial combined with bone-growth factors to enhance tendon-bone integration. However, which approach is better remains controversial. This comparison evaluation could help identify a suitable composite biomaterial for osteointegration of grafted tendon.


METHODS
Three different composite biomaterials mixed with bone morphological proteins (BMPs) were fabricated. The in vitro study investigates cell metabolism, osteogenic gene expression and the growth behaviour of bone marrow stromal cells (BMSCs) on fibrin glue-BMPs (FGB), calcium phosphate cement-BMPs (CPCB) and recombined bone xenograft (RBX), which are commercially, clinically available biomaterials. Meanwhile, the changes in the physical, morphological and mechanical properties between the three composites and the original biomaterials were also observed. The in vivo study mainly examined the osteogenic ability of the three composites through rat ectopic testing.


RESULTS
The porosity structure of three biomaterials was improved after being combined with BMPs powder for SEM observation, and the setting times of the injectable composites were not significantly delayed. More importantly, there were no significant decreases in compressive strength between the three composite biomaterials and the original biomaterials. The highest proliferation rate of BMSCs was found in the RBX group, followed by the CPCB and FGB groups. BMSCs seeded onto an RBX showed the highest alkaline phosphatase (ALPase) activity and gene expression of collagen I (P < 0.05). Histological examination showed endochondral new bone formation in the specimens of all groups, but the ALPase activity of newly formed tissue in the RBX group showed the highest level (P < 0.01).


CONCLUSIONS
Our results indicate that RBX seems to be a very good choice for accelerating tendon-bone integration, and CPCB also has a large potential ability to be used. However, these two composites still need to be modified, and we postulate that a combination of them would be more favourable for tendon osteointegration after ACL reconstruction than either composite used alone.
Department of Human Movement Studies, Xi'an Physical Education University, 710068 Xi'an, People's Republic of China. panweimin@163.com
Weimin
W
Pan
Zheng
Z
Cao
Dan
D
Li
Mingjun
M
Zhang
D000818:Animals; D016118:Anterior Cruciate Ligament / Q000166:cytology / Q000601:surgery*; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D001672:Biocompatible Materials / Q000737:chemistry*; D001854:Bone Marrow Cells / Q000166:cytology / Q000378:metabolism*; D019485:Bone Morphogenetic Proteins / Q000378:metabolism*; D002130:Calcium Phosphates / Q000737:chemistry*; D002454:Cell Differentiation; D049109:Cell Proliferation; D008297:Male; D051379:Mice; D011817:Rabbits; D013718:Tensile Strength
D001672:Biocompatible Materials; D019485:Bone Morphogenetic Proteins; D002130:Calcium Phosphates