An injectable conductive Gelatin-PANI hydrogel system serves as a promising carrier to deliver BMSCs for Parkinson's disease treatment.

Parkinson's disease (PD) is a long-term neurodegenerative disorders that characterized by a progressive loss of dopaminergic neurons in substantia nigra pars compacta (SNc). Bone marrow stromal cells (BMSCs) are promising therapeutic agents for neurodegenerative disease due to their multipotent capacity. To promote the potential therapeutic effect of BMSCs on PD, we developed an injectable Gelatin-PANI hydrogels as a novel carrier for delivering BMSCs to the SNc region in mice with PD by stereotactic injection. Histology results showed that the BMSCs-loaded hydrogels lead to increased numbers of tyrosine hydroxylase positive (TH+) dopaminergic neurons and fibers in the SNc and striatum, and increased expression of brain-derived neurotrophic factor (BDNF) and glial cell-derived neurotrophic factor (GDNF) in the SNc. Meanwhile, rotarod and open field evaluation demonstrated BMSCs-loaded hydrogels significantly improved the behavioral performance of PD mice. Importantly, BMSCs-loaded hydrogels imparted more sustained protective effects than BMSCs alone in PD mice. Overall, the current data indicate that the hydrogel serves as a promising carrier to deliver BMSCs to the SNc for the treatment of PD.