Superior synaptogenic effect of electrospun PLGA-PEG nanofibers versus PLGA nanofibers on human neural SH-SY5Y cells in a three-dimensional culture system

Abstract

In the present study, we evaluated the synaptogenic activity of electrospun PLGA and PLGA-PEG nanofibers on human SH-SY5Y cells after 14 days in vitro. Methods: Electrospun PLGA and PLGA-PEG nanofibers were fabricated and physicochemical properties were examined using the HNMR technique. The cells were classified into three random groups; Control (Laminin-coated surface), PLGA and PLGA-PEG groups. Scaffolds' features, cell morphology, attachment, and orientation were monitored by SEM imaging. We performed MTT assay to measure cell survival rate. To evaluate neurite formation and axonal outgrowth, cells were stained with an antibody against β3 tubulin using immunofluorescence imaging. Synapsin- 1 and synaptophysin were measured to explore the possible effect of PLGA and PLGA-PEG on synaptogenesis and functional activity of synapses.Results: According to SEM analysis, PLGA-PEG nanofibers' diameter was decreased relative to the PLGA scaffold alone. Cell attachment, expansion, neurite outgrowth and orientation were promoted in the PLGA-PEG group in comparison with the PLGA substrate. MTT assay revealed that both scaffolds did not exert any neurotoxic effects on cell viability. Notably, the PLGA-PEG increased cell viability compared to PLGA by time (p<0.05). Immunofluorescence staining indicated that the PLGA-PEG nanofibers promoted β3 tubulin levels after seven days coincided with axonal outgrowth and immature neurons relative to PLGA and control groups (p<0.05). Based on our data, both synaptogenesis and functional connectivity were induced in cells plated on PLGA-PEG by the increase of synapsin-1 and synaptophysin compared to the PLGA alone and control cells (p<0.05).