Synergistic Pharmacological Therapy to Modulate Glial Cells in Spinal Cord Injury

Current treatments for modulating the glial-mediated inflammatory response after spinal cord injury (SCI) have limited ability to improve recovery. This is quite likely due to the lack of a selective therapeutic approach acting on microgliosis and astrocytosis, the glia components most involved after trauma, while maximizing efficacy and minimizing side effects. A new nanogel that can selectively release active compounds in microglial cells and astrocytes is developed and characterized. The degree of selectivity and subcellular distribution of the nanogel is evaluated by applying an innovative super-resolution microscopy technique, expansion microscopy. Two different administration schemes are then tested in a SCI mouse model: in an early phase, the nanogel loaded with Rolipram, an anti-inflammatory drug, achieves significant improvement in the animal's motor performance due to the increased recruitment of microglia and macrophages that are able to localize the lesion. Treatment in the late phase, however, gives opposite results, with worse motor recovery because of the widespread degeneration. These findings demonstrate that the nanovector can be selective and functional in the treatment of the glial component in different phases of SCI. They also open a new therapeutic scenario for tackling glia-mediated inflammation after neurodegenerative events in the central nervous system. In this article, a nanogel that can selectively release active compounds in microglial cells and astrocytes in the spinal cord is developed and evaluated using expansion microscopy. Two administration schemes are tested in a spinal cord injury mouse model. Early treatment with Rolipram-loaded nanogel improves motor performance; late phase treatment has the opposite effect, worsening motor recovery due to widespread degeneration.image