Induction of Spontaneous Hyaline Cartilage Regeneration Using a Double-Network Gel

Kurokawa

et al. 2013

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BackgroundA double-network (DN) gel, which is composed of poly(2-acrylamido-2-methylpropanesulfonic acid) and poly(N,N’-dimethyl acrylamide), can induce hyaline cartilage regeneration in vivo in a large osteochondral defect. The purpose of this study was to clarify the influence of the thickness of the implanted DN gel on the induction ability of hyaline cartilage regeneration.MethodsThirty-eight mature rabbits were used in this study. We created an osteochondral defect having a diameter of 4.3-mm in the patellofemoral joint. The knees were randomly divided into 4 groups (Group I: 0.5-mm thick gel, Group II: 1.0-mm thick gel, Group III: 5.0-mm thick gel, and Group IV: untreated control). Animals in each group were further divided into 3 sub-groups depending on the gel implant position (2.0-, 3.0-, or 4.0-mm depth from the articular surface) in the defect. The regenerated tissues were evaluated with the Wayne’s gross and histological grading scales and real time PCR analysis of the cartilage marker genes at 4 weeks.ResultsAccording to the total Wayne’s score, when the depth of the final vacant space was set at 2.0 mm, the scores in Groups I, II, and III were significantly greater than that Group IV (p < 0.05), although there were no significant differences between Groups I and IV at a 3.0-mm deep vacant space. The expression levels of type-2 collagen in Groups II and III were significantly higher (p < 0.05) than that in Group IV.ConclusionsThe 1.0-mm thick DN gel sheet had the same ability to induce hyaline cartilage regeneration as the 5.0-mm thick DN gel plug. However, the induction ability of the 0.5-mm thick sheet was significantly lower when compared with the 1.0-mm thick gel sheet. The 1.0-mm DN gel sheet is a promising device to establish a cell-free cartilage regeneration strategy that minimizes bone loss from the gel implantation.

Section: Introductionmentioning

confidence: 78%

Influence of the gel thickness on in vivo hyaline cartilage regeneration induced by double-network gel implanted at the bottom of a large osteochondral defect: Short-term results

Matsuda

Kurokawa

et al. 2013

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“…Based on the previous studies reporting cartilage regeneration using a DN gel, the depth of the defect remained after the DN gel implantation is a critical factor on the cartilage regeneration induced by the DN gel: An approximately 2-mm deep vacant space above the DN gel is the most effective for cartilage regeneration in a mature rabbit femoral trochlea osteochondral defect model [17, 19–21], this suggests that the appropriate size of space is very important for regeneration of high quality cartilage tissue. The present study used a 2-mm depth model and showed cartilage regeneration in the vacant space independent on the defect size at 4 weeks.…”

Section: Discussionmentioning

confidence: 99%

“…In the right knee of each animal, a cylindrical DN gel plug was implanted at the bottom of each defect so that a 2-mm deep defect remained above the DN gel after surgery. The depth of 2 mm was chosen because this depth was found to be the most effective to induce the cartilage regeneration in our previous study with rabbits [17, 21]. In the left knee, a defect was left vacant without any implantation to obtain control data.…”

Section: Methodsmentioning

confidence: 99%

Effects of osteochondral defect size on cartilage regeneration using a double-network hydrogel

Higa

Goto

et al. 2017

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BackgroundThere has been increased interest in one-step cell-free procedures to avoid the problems related to cell manipulation and its inherent disadvantages. We have studied the chondrogenic induction ability of a PAMPS/PDMAAm double-network (DN) gel and found it to induce chondrogenesis in animal osteochondral defect models. The purpose of this study was to investigate whether the healing process and the degree of cartilage regeneration induced by the cell-free method using DN gel are influenced by the size of osteochondral defects.MethodsA total of 63 mature female Japanese white rabbits were used in this study, randomly divided into 3 groups of 21 rabbits each. A 2.5-mm diameter osteochondral defect was created in the femoral trochlea of the patellofemoral joint of bilateral knees in Group I, a 4.3-mm osteochondral defect in Group II, and a 5.8-mm osteochondral defect in Group III. In the right knee of each animal, a DN gel plug was implanted so that a vacant space of 2-mm depth was left above the plug. In the left knee, we did not conduct any treatment to obtain control data. Animals were sacrificed at 2, 4, and 12 weeks after surgery, and gross and histological evaluations were made.ResultsThe present study demonstrated that all sizes of the DN gel implanted defects as well as the 2.5mm untreated defects showed cartilage regeneration at 4 and 12 weeks. The 4.3-mm and 5.8-mm untreated defects did not show cartilage regeneration during the 12-week period. The quantitative score reported by O’Driscoll et al. was significantly higher in the 4.3-mm and 5.8-mm DN gel-implanted defects than the untreated defects at 4 and 12 weeks (p < 0.05). The 2.5-mm and 4.3-mm DN gel implanted defects maintained relatively high macroscopic and histological scores for the 12-week implantation period, while the histological score of the 5.8-mm DN gel implanted defect had decreased somewhat but statistically significantly at 12 weeks (p = 0.0057).ConclusionsThe DN gel induced cartilage regeneration in defects between 2.5 and 5.8 mm, offering a promising device to establish a cell-free cartilage regeneration therapy and applicable to various sizes of osteochondral defects.

“…Previous in vivo studies showed that the mechanical properties of the PAMPS/PDMAAm DN gel implanted in the subcutaneous tissue did not deteriorate at 6 weeks after implantation [10] and that although a pellet implantation test into the para-vertebral muscle induced a mild cell infiltration at 1 week, the degree of the inflammation significantly decreased to the same degree as that of the negative control at 4 and 6 weeks [21]. Furthermore, the shape or the position of the PAMPS/PDMAAm DN gel implanted in the bone defect was not much changed at 12 weeks after surgery compared to that at 4 weeks [2]. We also cultured ATDC5 cells on the PAMPS/PDMAAm DN gel [1] as well as the single-network PAMPS and PDMAAm gels [4,5].…”

Section: Discussionmentioning

confidence: 99%

Hyaluronic acid enhances the effect of the PAMPS/PDMAAm double-network hydrogel on chondrogenic differentiation of ATDC5 cells

Kurokawa

Fukui

et al. 2014

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BackgroundA double-network (DN) gel, which was composed of poly-(2-Acrylamido-2-methylpropanesulfonic acid) and poly-(N,N’-dimethyl acrylamide) (PAMPS/PDMAAm), has the potential to induce chondrogenesis both in vitro and in vivo. The present study investigated whether DN gel induced chondrogenic differentiation of ATDC5 cells in a maintenance medium without insulin, and whether supplementation of hyaluronic acid enhanced the chondrogenic differentiation effect of DN gel.MethodsATDC5 cells were cultured on the DN gel and the polystyrene (PS) dish in maintenance media without insulin for 21 days. Hyaluronic acid having a molecular weight of approximately 800 kDa was supplemented into the medium so that the concentration became 0.01, 0.1, or 1.0 mg/mL. The cultured cells were evaluated using immunocytochemistry for type-2 collagen and real time PCR for gene expression of type-2 collagen, aggrecan, and Sox9 at 7 and 21 days of culture.ResultsThe cells cultured on the DN gel formed nodules and were stained with an anti-type-2 collagen antibody, and expression of type-2 collagen and aggrecan mRNA was significantly greater on the DN gel than on the PS dish surface (p < 0.05) in the hyaluronic acid-free maintenance medium. Hyaluronic acid supplementation of a high concentration (1.0 mg/mL) significantly enhanced expression of type-2 collagen and aggrecan mRNA in comparison with culture without hyaluronic acid at 21 days (p < 0.05).ConclusionsThe DN gel induced chondrogenic differentiation of ATDC5 cells without insulin. This effect was significantly affected by hyaluronic acid, depending on the level of concentration. There is a high possibility that hyaluronic acid plays an important role in the in vivo hyaline cartilage regeneration phenomenon induced by the DN gel.