Ligament repair: a molecular and immunohistological characterization.
The anterior cruciate ligament (ACL) is the most commonly injured tissue of the human knee. Its poor ability to regenerate after injury represents a challenge to ligament tissue engineering. An understanding of the molecular composition of the structures used for its repair is essential for clinical assessments and for the implementation of tissue engineering strategies. The objective of this study was to evaluate, both at gene and protein levels, the expression of characteristic molecules in human ACL, patellar, semitendinosus and gracilis tendons and in the ligament reconstructed with patellar or semitendinosus and gracilis tendons. We demonstrated that primary ACL and tendon tissues all express collagen I, II, Sox-9, tenascin-C and aggrecan. Collagen X expression was detected at very low levels or undetectable. Cathepsin B, MMP-1 and MMP-13 were expressed at higher levels in the ACL reconstructed by the two tendons, showing that a remodeling process occurs during "ligamentization". Both our molecular and immunohistochemical evaluations did not reveal significative differences between the tendons and ligaments analyzed. However, ACL reconstructed with semitendinosus and gracilis tendon seems to present a higher expression of collagen type II when compared to that reconstructed with patellar tendon. This study could give a reasonable identification of genetic and protein markers specific to tendon/ligament tissues and be helpful in testing tissue engineering approaches for ACL reconstruction.
Roseti
L
L
Laboratorio di Immunologia e Genetica, Istituto di Ricerca Codivilla Putti, Istituti Ortopedici Rizzoli, Via di Barbiano 1/10, 40136 Bologna, Italy.
Buda
R
R
Cavallo
C
C
Desando
G
G
Facchini
A
A
Grigolo
B
B
D000328:Adult; D016118:Anterior Cruciate Ligament / Q000276:immunology* / Q000378:metabolism*; D000070598:Anterior Cruciate Ligament Injuries; D002401:Cathepsin B / Q000378:metabolism; D003094:Collagen / Q000378:metabolism; D005786:Gene Expression Regulation / Q000235:genetics; D006609:High Mobility Group Proteins / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D020781:Matrix Metalloproteinase 1 / Q000378:metabolism; D053509:Matrix Metalloproteinase 13 / Q000378:metabolism; D016133:Polymerase Chain Reaction; D011509:Proteoglycans / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D055758:SOX9 Transcription Factor; D019063:Tenascin / Q000378:metabolism; D013997:Time Factors; D014157:Transcription Factors / Q000378:metabolism
D006609:High Mobility Group Proteins; D011509:Proteoglycans; D012333:RNA, Messenger; D055758:SOX9 Transcription Factor; C527932:SOX9 protein, human; D019063:Tenascin; D014157:Transcription Factors; D003094:Collagen; D002401:Cathepsin B; D053509:Matrix Metalloproteinase 13; D020781:Matrix Metalloproteinase 1