Shoulder and Elbow Surgery Unit, Traumatology and Orthopaedic Surgery, Hospital Clinico San Carlos, Madrid, Spain.
Tissue Regeneration Group, Biofunctional Studies Institute, Universidad Complutense de Madrid (IEB-UCM), Spain.
Injury. 2021 Jan;52(1):78-84. doi: 10.1016/j.injury.2020.11.019. Epub 2020 Nov 9.
Rotator cuff disorders present a high retear rate despite advances in surgical treatment. Tissue engineering could therefore be interesting in order to try to enhance a more biological repair. RhBMP-2 is one of the most osteogenic growth factors and it also induces the formation of collagen type I. However, it has a short half-life and in order to get a more stable release over time it could be integrated in a more slowly degradable carrier, such as an alginate-chitin scaffold. The aim of this study was to investigate the role of the alginate-chitin scaffold alone and in combination with different concentrations of rhBMP-2 when applied on chronic rotator cuff lesions in a rat model.
We performed an experimental study with 80 Sprague-Dawley rats, 8 months old, with a chronic rupture of the supraspinatus tendon that was repaired with a modified Mason Allen suture. A scaffold was applied over the suture and 4 groups were obtained; suture (S) only suture, double control (DC) alginate and chitin scaffold, single sample (SS) scaffold of alginate with rhBMP-2 (20 µg rhBMP-2) and chitin, double sample (DS) a scaffold containing alginate with rhBMP-2 and chitin with rhBMP-2 (40 µg rhBMP-2). Macroscopic, histological and biomechanical studies were performed at 4 months after reparation.
The modified Åström and Rausing's histological scale (the higher the score the worse outcome, 0 points=native tendon) was applied: S got 52 points compared to DC 30 (p = 0,034), SS 22 (p = 0,009) and DS 16 (p = 0,010). Biomechanically the maximum load was highest in DC (63,05 N), followed by DS (61,60 N), SS (52,35 N) and S (51,08), p = 0,025 DS vs S. As to the elastic constant a higher value was obtained in DC (16,65), DS (12,55) and SS (12,20) compared to S (9,33), p = 0,009 DC vs S and 0,034 DS vs S.
The alginate-chitin scaffold seems to promote a more biological response after the reparation of a chronic rotator cuff lesion. Its effect is further enhanced by the addition of rhBMP-2 since the osteotendinous junction is more native-like and has better biomechanical properties.
尽管在外科治疗方面取得了进步，但肩袖疾病仍存在较高的再撕裂率。因此，组织工程可能很有趣，因为它可以尝试增强更具生物性的修复。RhBMP-2 是最具成骨活性的生长因子之一，它还可以诱导 I 型胶原的形成。然而，它的半衰期较短，为了获得更稳定的持续释放，它可以整合到更慢降解的载体中，如藻酸盐-壳聚糖支架。本研究的目的是研究藻酸盐-壳聚糖支架单独应用以及与不同浓度 rhBMP-2 联合应用于大鼠慢性肩袖损伤模型中的作用。
我们对 80 只 8 个月大的 Sprague-Dawley 大鼠进行了一项实验研究，这些大鼠患有慢性冈上肌腱撕裂，采用改良 Mason Allen 缝线修复。在缝线上应用支架，得到 4 组；缝线（S）仅缝线、双对照（DC）藻酸盐和壳聚糖支架、单样本（SS）含 20μg rhBMP-2 的藻酸盐支架和壳聚糖、双样本（DS）含 rhBMP-2 的藻酸盐和壳聚糖支架（40μg rhBMP-2）。在修复后 4 个月进行了宏观、组织学和生物力学研究。
应用改良Åström 和 Rausing 的组织学评分（评分越高，结果越差，0 分=正常肌腱）：S 组得分为 52 分，而 DC 组为 30 分（p=0.034），SS 组为 22 分（p=0.009），DS 组为 16 分（p=0.010）。生物力学方面，最大载荷在 DC 组最高（63.05N），其次是 DS 组（61.60N）、SS 组（52.35N）和 S 组（51.08N），p=0.025 DS 与 S 比较。至于弹性常数，DC 组（16.65）、DS 组（12.55）和 SS 组（12.20）的数值高于 S 组（9.33），p=0.009 DC 与 S 比较，p=0.034 DS 与 S 比较。
藻酸盐-壳聚糖支架似乎可以促进慢性肩袖损伤修复后的更具生物性反应。通过添加 rhBMP-2，其效果进一步增强，因为腱骨交界处更类似于原生组织，具有更好的生物力学性能。
