Reconstruction Of Large Rotator Cuff Tears With Acellular Extracellular Matrix And PRP In Rabbits

1ObjectiveThe main purpose of the experiment is to study the reconstruction of large rotator cufftears with acellular extracellular matrix and PRP in rabbits. It may be possible to bridgelarge rotator cuff tears with the acellular extracellular matrix (AEM). Platelet-rich plasma(PRP), rich in high concentrations of growth factors，has the potential to enhance thehealing of rotator cuff tears. So it will be helpful to the alteration of the biomechanical andhistologic properties in repair of a large rotator cuff tears，if we combine AEM with PRP.2Materials and methods58adult male SD Newzland white rabbits were divided randomly into four groups：normal group（n=4），model group of large rotator cuff tears（n=18），treatment groupwith AEM patch（A group，n=18），treatment group with AEM patch and PRP（B group，n=18）. Normal group was without any intervention. In other three groups，a1.5×1.5cmtendon lesion from bone rotator cuff tear was created on greater tubercle of humerus ofboth shoulder supraspinatus muscles of adult male New Zealand white rabbits. A groupunderwent reconstruction of the rotator cuff defect with an AEM patch. B group underwentreconstruction of the rotator cuff defect with an AEM patch and PRP. In the model groupno repair was performed. In model group and two treatment groups，executed six rabbits at4,8and12week after surgery respectively and took specimens of both shoulders. Thespecimens of two rabbits were subjected to histological analysis and the other were usedfor biomechanical testing. The specimens of four rabbits in normal group were subjected tobiomechanical testing at12week.3Results:On gross examination，poor healing at4and8week and the development of scartissue at12week were observed in model group. In the two treatment groups，at4weekthe healing of tendon and bone were not found. While at8and12week，we could observe well healing of tendon and bone. On microscopic examination，compared to A group，theamount of collagen fibers in B group was more large，the appearance more rough and thearrangement more order at8and12week. The results of biomechanical testing showedthat the largest tendon load in treatment groups appeared a general uptrend with thedevelopment of time（compared among each point，p<0.01）. However，the largest tendonload of two treatment groups was not different from each other in statistics at all timepoints(p>0.05). But the largest tendon load at12week was still lower than normal group（p<0.05).4Conclusion:The large rotator cuff defect could not mend themselves. AEM patch could repairlarge rotator cuff defects. Combining PRP into AEM patch，it is able to accelerate healingof the tendon. While it is useless in the increase of biomechanical intensity.