We have made three types of poly (DL-lactide-coglycolide) (PLG) scaffolds (porosity: scaffold I 80±0.9%, II 85±0.8%, III 92±0.7%; compression module determined with 10% strain: scaffold I 0.26 MPa, II 0.091 MPa, III 0.0047 MPa). Osteochondral defects made in the femoral condyle of rabbits were treated with these scaffolds and the possibilities of cartilage repair were investigated histologically. At post-operative weeks 6 and 12, histological scores in the groups of scaffolds II and III were significantly higher than the score in the group of scaffold I. Scaffolds II and III, which have higher porosity than scaffold I, allow better migration of bone marrow cells and better replacement of the scaffold with bone and cartilage than scaffold I. This study suggests that higher porosity allowing bone marrow cells to migrate to the scaffold is important in repairing osteochondral defects.Résumé Nous avons réalisé trois types de montage PLG (DL lactide co glycolide) avec des porosités différentes (montage I à 0,9%, montage II à 87 ,8%, montage III 0,7%). Avec le module de compression a été imposée une tension de 10% avec 0,26 MPa au niveau de la pièce I, 0,091 Mpa en montage II et 0,0047 MPa en montage III). Un defect ostéochondral réalisé dans le condyle fémoral d'un lapin a été traité par ces trois procédés avec une possibilité de réparation cartilagineuse. Cette possibilité a été évaluée histologiquement. A 6 et 12 semaines postopératoires, le score histologique dans les groupes II et III sont significativement plus élevés que dans le groupe I. Les pièces II et III qui ont une plus grande porosité que la I permettent une meilleure migration des cellules de la moelle osseuse et une meilleure réparation de l'os et du cartilage que dans le montage I. Cette étude nous permet de penser qu'une porosité plus importante permet la migration plus facile de ces cellules de moelle osseuse lors de la réparation des défects ostéochondraux.

A successful scaffold for use in tendon tissue engineering requires a high affinity for living organisms and the ability to maintain its mechanical strength until maturation of the regenerated tissue. We compared two types of poly(L-lactic acid) (PLLA) scaffolds for use in tendon regeneration, a plain-woven PLLA fabric (fabric P) with a smooth surface only and a double layered PLLA fabric (fabric D) with a smooth surface on one side and a rough (pile-finished) surface on the other side. These two types of fabric were implanted into the back muscles of rabbits and evaluated at three and six weeks after implantation. Histological examination showed collagen tissues were highly regenerated on the rough surface of fabric D. On the other hand, liner cell attachment was seen in the smooth surface of fabric P and fabric D. The total DNA amount was significantly higher in fabric D. Additionally, mechanical examination showed fabric P had lost its mechanical strength by six weeks after implantation, while the strength of fabric D was maintained. Fabric D had more cell migration on one side and less cell adhesion on the other side and maintained its initial strength. Thus, a novel form of double-layered PLLA fabric has the potential to be used as a scaffold in tendon regeneration.

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Vascular endothelial growth factor (VEGF) plays a critical role in chondrogenic differentiation in the growth plate of the epiphysis. This function is necessary for chondrocyte survival in cartilage development. We investigated the localization of VEGF in the osteochondral regeneration process using a bioabsorbable polymer scaffold. Osteochondral defects (5 mm in diameter and 5 mm in depth) were made on the femoral condyle of forty-eight skeletally mature female Japanese white rabbits. In total, twenty-four defects were filled with poly(DL-lactide-co-glycolide) scaffolds and the others were left untreated. The regeneration process was investigated macroscopically, histologically, immunohistochemically, and by gene expression analysis. In the early stages of osteochondral regeneration, bone ingrowth was observed in the deep zone of the scaffold with continuous VEGF expression; cartilage regeneration was observed in the superficial zone of the scaffold with decreased VEGF expression. In contrast, when the defect was left untreated, VEGF localization was observed throughout the entire defect area, and cartilage regeneration at the articular surface was delayed. We conclude that decrease in localization of VEGF at the articular surface in the postoperative early stage is closely related to the progression of cartilage regeneration in osteochondral defects. ß

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Mycobacterial tuberculous tenosynovitis of the hand is a rare manifestation of extrapulmonary tuberculosis, while mycobacterial tuberculous tenosynovitis of the extensor tendon sheath is extremely rare. We report a case of tuberculous tenosynovitis of the extensor tendon of the finger, occurring in a man receiving immunosuppression following a liver transplantation. Symptoms improved clinically after conservative treatment with anti-tuberculous drugs.

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