EFFECTS OF IONIC DISOLUTION PRODUCTS RELEASED FROM BIOACTIVE GLASSES ON THE NEUROREGENERATION IN A NOVEL ANIMAL MODEL FOR BIOMATERIALS STUDIES

In regenerative medicine of the Central Nervous System (CNS), the limited recovery of functional neurons after injury remains a major challenge. Although stem cells, neurotrophic factors, and biomaterial-based therapies are promising, no ideal strategy has yet been established. Third-generation biomaterials, such as Bioactive Glasses (BGs), can release ions that stimulate cellular responses. Among them, Boron (B) ions exhibit neuroprotective and anti-neuroinflammatory effects, suggesting that their controlled release could enhance neural repair. In parallel, there is growing interest in using invertebrate models to replace vertebrates in basic neuroscience research. The planarian Schmidtea mediterranea represents an attractive model due to its vertebrate-like neural types and conserved molecular pathways involved in CNS regeneration. This study evaluated the effects of Ionic Dissolution Products (IDPs) from BGs within the Na₂O–B₂O₃–SiO₂ system, containing 18.75 and 37.5 mol% B₂O₃, on planarian neuroregeneration. IDPs were obtained by incubating BG microparticles in planarian artificial medium for 24–72 hours, and IDPs were characterized by ICP-OES. Planarians (4–6 mm) were amputated at pre and post-pharyngeal level, and the resulting trunks were exposed to IDPs at 20 ± 1°C. After seven days, regenerating animals were analyzed for TH, GAD, and OVO gene expression via in situ hybridization. Exposure to low B concentrations (0.38–0.54 mM) increased gene expression, whereas higher concentrations (>5 mM) reduced expression and caused abnormal regeneration. These results are consistent with previous findings in rodents and in vitro models, supporting S. mediterranea as a suitable alternative model for studying BG-derived IDPs in neuroregeneration.