Protective effects of silk fibroin against 6-OHDA in SH-SY5Y human neuroblastoma cells and comparative study with its release from gelatin films

In this study, we analyzed the neuroprotective action of silk fibroin (SF) regenerated with calcium chloride (CaCl2), distinguishing the effects of CaCl2 and SF, and subsequently fabricating a neuroprotective hybrid material based on SF gelatin film. Cytotoxicity induced by 6-hydroxydopamine (6-OHDA) on the human neuroblastoma SH-SY5Y cell line showed that SF had a significant shielding power against 6-hydroxydopamine (6-OHDA)-induced neurotoxicity in SH-SY5Y neuroblastoma cells, as assessed by the CCK-8 assay, cell imaging and cell cycle using flow cytometer. Specifically, the concurrent treatment with SF and 6-OHDA produced a marked neuroprotective effect. Circular dichroism analysis suggested the formation of silk III because of the interaction between the secondary structures of SF and 6-OHDA. Raman analysis was also employed to assess the impact of SF and CaCl2 on cellular metabolism, indicating the combined administration of fibroin and 6-OHDA as more effective than the use of CaCl2 alone. Subsequently, we synthesized a silk/gelatin-based film, demonstrated its ability to release SF, and confirmed its capacity to protect SH-SY5Y neuroblastoma cells.