title: Hyaluronic acid-based hydrogel enhances neuronal survival in spinal cord slice cultures from postnatal mice.
abstract: Numerous biomaterials based on extracellular matrix-components have been developed. It was our aim to investigate whether a hyaluronic acid-based hydrogel improves neuronal survival and tissue preservation in organotypic spinal cord slice cultures. Organotypic spinal cord slice cultures were cultured for 4 days in vitro (div), either on hyaluronic acid-based hydrogel (hyaluronic acid-gel group), collagen gel (collagen group), directly on polyethylene terephthalate membrane inserts (control group), or in the presence of soluble hyaluronic acid (soluble hyaluronic acid group). Cultures were immunohistochemically stained against neuronal antigen NeuN and analyzed by confocal laser scanning microscopy. Histochemistry for choline acetyltransferance, glial fibrillary acidic protein, and Griffonia simplicifolia isolectin B4 followed by quantitative analysis was performed to assess motorneurons and different glial populations. Confocal microscopic analysis showed a 4-fold increase in the number of NeuN-positive neurons in the hyaluronic acid-gel group compared to both collagen (p < 0.001) and control groups (p < 0.001). Compared to controls, organotypic spinal cord slice cultures maintained on hyaluronic acid-based hydrogel showed 5.9-fold increased survival of choline acetyltransferance-positive motorneurons (p = 0.008), 2-fold more numerous resting microglial cells in the white matter (p = 0.031), and a 61.4% reduction in the number of activated microglial cells within the grey matter (p = 0.05). Hyaluronic acid-based hydrogel had a shear modulus (G') of ≈1200 Pascals (Pa), which was considerably higher than the ≈25 Pa measured for collagen gel. Soluble hyaluronic acid failed to improve tissue preservation. In conclusion, hyaluronic acid-based hydrogel improves neuronal and - most notably - motorneuron survival in organotypic spinal cord slice cultures and microglial activation is limited. The positive effects of hyaluronic acid-based hydrogel may at least in part be due to its mechanical properties.
authors.affiliation: 1The SpineLab, Institute of Surgical Sciences, Department of Orthopaedics, Uppsala University, Uppsala, Sweden.
authors.forename: Nikos
authors.initials: N
authors.lastname: Schizas
authors.forename: Ramiro
authors.initials: R
authors.lastname: Rojas
authors.forename: Sujit
authors.initials: S
authors.lastname: Kootala
authors.forename: Brittmarie
authors.initials: B
authors.lastname: Andersson
authors.forename: Jennie
authors.initials: J
authors.lastname: Pettersson
authors.forename: Jons
authors.initials: J
authors.lastname: Hilborn
authors.forename: Nils P
authors.initials: NP
authors.lastname: Hailer
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D002470:Cell Survival; D006820:Hyaluronic Acid / Q000737:chemistry*; D020100:Hydrogels; D051379:Mice; D018613:Microscopy, Confocal; D009474:Neurons / Q000166:cytology*; D009924:Organ Culture Techniques; D013116:Spinal Cord / Q000166:cytology*
chemical_list: D001672:Biocompatible Materials; D020100:Hydrogels; D006820:Hyaluronic Acid
keywords: Neuroprotection; apoptosis; extracellular matrix-based biomaterials; hyaluronic acid-based hydrogel; microglial cells; motorneurons