| Background and objective:Massive rotator cuff tear is a surgical problem of shoulder surgery.With the continuous improvement of quality of everydaylife and aging patients shoulder degeneration increasing,the current number of patients is creasing in clinical rotator cuff tears.Rotator cuff tear was not only a pure surgical repair result poorly,postoperative failure percentage higher than that many massive rotator cuff tears or even couldn't repair.In order to overcome the shortcomings of surgical treatment of rotator cuff injury related technologies including tendon transposition,tissue transplantation has achieved certain results in certain aspects.But many surgical procedures to change the shoulder anatomy and biomechanics function the patient immune rejection.Ideally,how to reconstruct the normal physiological structure of the tendon-to-bone interface of the ascending tendon is still the key to the reconstruction of the rotator cuff tears.The purpose of this study was authorized to evidence the feasibility and safety of simple manipulation of silk fibroin biological patch in animal experiments.By observing the change of histomorphology and biomechanics,we would evaluated the tendon-bone interface healing protein treatment theory and practice basis of the future clinical application to provide experimental references.Methods:Part ?:96 healthy male New Zealand white rabbits were randomly divided into four groups(twenty-four rats per group).An injury rabbit RCT model to be established,right forelimb supraspinatus tendons were surgically transected completely and repaired with a technique on the basis of a well-established silk fibroin biological patch.The rabbits were sacrificed at 8 and 16 weeks after operation and specimen consist of the supraspinatus and proximal of humerus collected.All the supraspinatus consist of tendon-to-bone were attached well in order to detect the silk fibroin biopatches situation in living tissue.We collected the fresh immediately specimen to deal with frozen machine slices not paraffin slices.The samples were fixed in 10%formalin and decalcified in methy-methacrylate compound,conventional tissue treatment.Specimens were sectioned parallel or perpendicular to the sagittal axis of the complexes consist of tendon-to-bone interface at a thickness of 6 ?m labeled.Growth healing of the interface was observed by means of hematoxylin&eosin(H&E)and masson trichrome staining analysis performing light microscopy at 8 and 16 weeks:vascularity,tendon fiber arrangement and structure variations.Part II:96 healthy male New Zealand white rabbits were selected and randomly divided into four groups.24 rabbits of each group,and the right front limb was made model same as before.The content of TGF-?1 and IGF-1 was detected by ELISA.The concentration of the maximum load(N),stiffness(N/mm),elastic modulus(Mpa)and displacement(mm)were measured at 8 and 16 weeks after operation.Results:Part ?:Effects of hematoxylin and eosin staining on histology changes:Fresh vascular proliferation and cartilage orderly arrangement was observed in 96 rabbits of 4 groups at the same time point.Firstly,the results of light microscopy showed that at 8 weeks after operation the tendon-bone interface of the sham group(Sham)and the low-dose group(L-dose)were filled with inflammatory cells,and the fresh granulation tissue of the high-dose group(H-dose)active more than the newborn capillaries in normal group(Normal).The number of inflammatory cells in the bone interface and its adjacent areas was significantly reduced,and the transition from fresh granulation cells to tendon tissue cells and the penetration of bone-to-tendon tissue were dominant.At 16 weeks after operation,the proliferation of newborn bone and tendon tissue of the H-dose of L-dose groups were more obvious,and the connective tissue gradually inserted into the interfacial gap of tendon-to-bone.The number of fibroblasts in the sham was significantly comparison of the normal group,and the number of growth and speed evident obviously.Secondly,collagen-type-?expression results at 8 weeks after surgery in both silk fibroin biological patch groups positive staining of collagen,dying depth and areaes size was not increased significantly compared with the samples in sham group.Collagen-type-? of normal group(Normal)was red and bright white at 8 weeks postoperatively.The sham consisted of bright white collagen-type-? fibers and red,which were observed improved significantly the expression compare to normal group.The H-dose showed mainly in slim Green collagen-type-?,and the color of the staining lower and uniform in the L-dose.L-dose showed a small amount of yellow collagen-type-? and collagen-type-? fiber.The positive distribution after 16 weeks operation of collagen-type-? in the L-dose was more extensive than 8 weeks,and the arrangement relatively ordered.The collagen-type-? of H-dose was evenly distributed and increased obviously compared with L-dose at 16 weeks.The collagen-type-? of L-dose was relatively much orderly comparison to sham groups.Finally,ELISA revealed the Level of TGF-?1 and IGF-1 protein test results:the level of TGF-?1 and IGF-1 protein at 8 weeks after surgery were significantly much lower compared with the H-dose or L-dose.The statistics differences of four groups showed significantly(P<0.05).At 16 weeks,the levels of TGF-?1 protein in the H-dose and L-dose increased,and the level of TGF-?1 protein was significantly higher compared with to the sham(P<0.05).The level of IGF-1 protein increased at the 16 weeks after operation,and there was significantly differences between the two dose groups and normal group(P>0.05).There was no significant difference in the sham compared to normal groups(P>0.05).The results showed that silk fibroin biological patch could promote the process of repairing the tendon-to-bone interface of rabbits rotator cuff,improving the postoperative tendon-bone interface collagen-type-? and TGF-?1,IGF-1 protein expression,thus promoting the rotator cuff tears of the posterior tendon-to-bone repair.Part ?:mechanical results:The maximal load of tendon-bone interface was significant(P=0.000),and the maximum load of tendon-bone interface in H-dose at each time point was significantly higher than that of L-dose and sham(P=0.000).The maximal load of tendon-bone interface was 140.74%and 145.63%in the sham group at 8 and 16 weeks(P = 0.000,P<0.05).The stiffness value of tendon-bone interface in H-dose was significantly difference compare with that of L-dose at same time point after operation(P = 0.000,P<0.05).The numerical of stiffness of tendon-to-bone interface in the L-dose was 130.99%and 141.90%at 8 and 16 weeks after operation.The results showed that the maximal load of the tendon in the two dose groups a continuous upward trend over time(P<0.05,after operation each time point).At the same time point,the maximum load value in the L-dose was significantly higher compare with the sham(P<0.05).The maximal load in H-dose was difference significantly compare with the L-dose(P<0.05).There was significant difference compare with the H-dose and L-dose at 16 weeks postoperative(P = 0.000,P<0.05).Conclusions:? The effect of silk fibroin biological patch on Histology and expression of collagen-type-III in the process of tendon-to-bone repair after rabbit rotator cuff tears confirmed that it has promoted the repair of tendon-bone interface.? Silk fibroin biological patch plays a role in stength,which can induce the specific structure of the tendon-bone interface after the operation,which can significantly improved the tensile strength and stiffness of the tendon-to-bone interface and promote healing.? This study shows that silk fibroin biological patch repaired the tendon-to-bone interface in promoting the clinical application of a role of certain degree. |
PDF Full Text Request