Alginate-based hydrogel inks are commonly used in printing due to their biocompatibility, biodegradation, and cell adhesion. In the present work, 3D printing of hydrogels comprising alginate/methyl cellulose (MC)/trimethyl chitosan (TMC) and silicate glasses was investigated. It was found that TMC increased the stability of the scaffolds after immersion in normal saline solution in comparison with alginate/MC 3D constructs. The stability also remained after the incorporation of pure silicate glasses or bioactive glasses. Immersion in simulated body fluid (SBF) resulted in the formation of hydroxyapatite in all samples. Scanning electron microscopy (SEM) analysis revealed a good cell adhesion of pre-osteoblasts on all scaffold compositions, cell viability assessment displayed a proliferation increase up to seven days in culture, and alkaline phosphatase (ALP) activity was similar in all scaffold compositions without significant differences. Total collagen secretion by the pre-osteoblasts after 7 days in culture was significantly higher in scaffolds containing silicate glasses, demonstrating their ability to promote extracellular matrix formation. In conclusion, 3D-printed porous scaffolds based on alginate/methyl cellulose/TMC are promising candidates for bone tissue engineering applications. Full article

Peritendinous adhesions are a frequent occurrence following tenolysis and present a major clinical challenge regarding prevention and management, with no recovery assured from conservative or surgical approaches. Herein, we investigated the effectiveness of Hyaloglide^®, a hyaluronan gel-based product with a novel autocross-linked technology, in a rabbit model affected by tenolysis on the flexor digitorum communis tendon (FDC). A 1.5-cm-long scrubbing of the tendon surface was performed bilaterally to induce peritendinous adhesion on FDC of 30 animals with subsequent application of Hyaloglide^® on the surrounding injured area, in one randomly chosen tendon. The contralateral tendon was treated with saline solution as the control. We sacrificed the rabbit models after 45 days of surgery and quantitatively assessed the generation of peritendinous adherence and regeneration of the tendon sheaths using histological (hematossyline-eosine, masson’s trichromic), histomorphometrical (Tang score, Soslowsky Svesson, and Cook score), light electron microscopic, and gene expression investigations. Four rabbits were devoted to biomechanical analysis. Peritendinous adhesions were limited in Hyaloglide^®-treated tendons; moreover, well-regenerated tendon sheaths were observed conversely to untreated tendons presenting with extensive areas of adhesions on the tendon surface. Histomorphometrical analysis revealed an adhesion score (Tang score) significantly better in the treated group (p = 0.001 *) compared to the control group. Moreover, the Soslowsky, Svensson, and Cook score parameters revealed a significantly improved regeneration for fiber structure, cellularity, and vascularity in the treated group (p = 0.001 *). No differences were reported for cartilaginous formation (p = 0.08). Gene expression analysis showed a significant increase in collagen type I expression in the treated group compared to the control group, while metalloprotease 1 and 9 were significantly increased in the control group. Biomechanical analysis did not show significant differences in both groups. Hyaloglide^® treatment was safe and well-tolerated, generating improved tissue status. Local application of Hyaloglide^® prevents adhesion formation after tenolysis and promotes normal healing with regeneration of the synovial sheath in a rabbit model. Full article