Objective The tendon-bone heal ing is the key point to ensure the success of the anterior cruciate l igament (ACL) reconstruction. To observe the histological change in the tendon-bone heal ing after ACL reconstruction by different concentrations of platelet-rich plasma (PRP) combined with deproteinized bone (DPB) of calf as bone tunnel infill ing and to investigate the active effect of the complex on tendon-bone heal ing and to define the optimal concentration of PRP. Methods Eight mL blood was drawn from central artery of New Zealand rabbit ears; PRP was prepared by Landesbergmethod, and l iquid supernatant was used as thinner to prepare different concentrations of PRP (30%, 60%, and 100%). Fresh osteoepiphysis spongy bone was harvested from lower end of femur of newborn calf to prepare DPB by way of 30% H2O2 and ether alternating soaking for 24 hours continuous 6 times. DPB was soaked in different concentrations of PRP and mixed with activator to prepare the PRP/DPB complex. A total of 54 New Zealand white rabbits, aging 8-12 months, weighing (2.5 ± 0.4) kg, were divided randomly into 3 groups: group A (30%PRP/DPB complex, n=18), group B (60%PRP/DPB complex, n=18), and group C (100%PRP/DPB complex, n=18). The legs of the rabbits were randomly divided into experimental side and the control side; ACL was reconstructed by semitendinosus and PRP/DPB complex in bone tunnel in the experimental side, and only by semitendinosus in the control side. The general conditions of the rabbits were observed postoperatively and HE staining was used to observe the tendon-bone heal ing, then I-IV levels of semi-quantitative analysis of the tendon-bone heal ing were evaluated according to Demirag standard at 3, 6, and 12 weeks. Results General observation: Synovial fluid sl ightly increased in the specimens and no bony tissue was found in inner of femoral tunnel at 3 weeks; there was no synovial fluid in all the specimens and scar tissue was discovered in inner of femoral tunnel at 6 weeks; and there was no synovial fluid and the tendons became tighter with fibrous tissue at 12 weeks. Histological observation: New granulation tissue formed in the tendon-bone interface of group A experimental sides at 3 weeks; there was various widths of Sharpey type textile fiber in the tendon-bone interface at 6 weeks; Sharpey type textile fiber arranged regularly, which formed an irregular and blur “tidal l ine” at 12 weeks. Group B experimental sides were better than any other group at 3, 6, and 12 weeks; chondrocyte-l ike arranged regularly in the tendonboneinterface at 3 weeks; the number of chondrocyte-l ike per unit area was more than that of the other groups at 6 weeks;and chondrocyte-l ike prol iferated and matured in the tendon-bone interface, Sharpey type textile fiber became tighter andordered. Group C experimental sides were similar to both sides of group A at 3 weeks, however, the prol iferation of relatively mature dense connective tissue was worse than that of other groups at 6 and 12 weeks. According to Demirag grading, there were significant differences in tendon-bone heal ing between the experimental sides and the control sides of group B at 3 and 6 weeks, and between group B experimental sides and group C experimental sides at 12 weeks (P lt; 0.05). Conclusion The mixture of PRP/PRP has good biocompatibil ity and bone induction, so it can enhance tendon-bone heal ing after ACL reconstruction when the concentration of PRP is 60%.
ObjectiveTo explore the effect of the expanded capsule on the growth of autogenous costal cartilage. MethodsSixteen New Zealand white rabbits at the age of 3 months (weighing, 2.2-2.5 kg; male or female) were selected and four 15 mL tissue expanders were implanted on the back symmetrically. After 1 month, the expanded capsule formed, the tissue expanders were removed; the capsule of the left side was removed (experimental group), and the capsule of the right side was reserved (control group); meanwhile, the right 7th and 8th costal cartilage without the perichondrium was divided into segments and placed into the capsule of 2 groups symmetrically. At 4 and 8 weeks after transplantation, the cartilage was harvested for the general, weighing, and histological observations. ResultsOne rabbit died during the experiment, and the other 15 rabbits survived. The differences of cartilage weight between before and after transplantation showed more obvious increase in the experimental group[(0.003 4±0.002 7) g and (0.005 8±0.001 4) g] than those in the control group[(-0.000 3±0.001 9) g and (-0.003 9±0.005 3) g] at 4 and 8 weeks, showing significant differences between 2 gouprs (t=4.331, P=0.029; t=6.688, P=0.008). The change of cartilage weight at 8 weeks was significantly higher than that at 4 weeks in the experimental group (t=-3.098, P=0.001); but the change of cartilage weight at 8 weeks was significantly lower than that at 4 weeks in the control group (t=2.491, P=0.009). The histological observation showed that the activity of the cartilage was enhanced in 2 groups at 4 and 8 weeks when compared with normal cartilage, and more obvious change was observed in the experimental group than in the control group. And the acellular area was seen in the cartilage at 8 weeks in the control group. The Masson staining results showed that the color was deeper in the experimental group than in the control group. ConclusionThe removal of the expanded capsule during operation is beneficial to the growth of autogenous costal cartilage. The results can provide corresponding experimental guidance for the clinical problems.