Activated olfactory ensheathing cells suppress astrocyte reactivity and CSPGs expression through IL-10 signaling in an in vitro scratch-injury model of glial scarring.

Following spinal cord injury (SCI), astrocytes undergo robust activation, migrate toward the lesion area, extend overlapping processes, and secrete abundant chondroitin sulfate proteoglycans (CSPGs), which inhibit axonal regeneration. To investigate how activated olfactory ensheathing cells (aOECs) modulate astrocyte activity and CSPG expression following mechanical scratch (MS), we established an in vitro scratch-injury model using primary astrocytes cultured from neonatal SD rats. The scratch injury induced a time-dependent upregulation of GFAP, vimentin, neurocan, and NG2 in astrocytes. However, astrocytes cultured in DMEM/F12 exhibited an unexpected decrease in GFAP expression, suggesting that the medium composition may influence GFAP protein turnover. Curcumin treatment effectively activated OECs, promoting their proliferation and elevating their expression of PSR and TG2. Compared to OECs, aOECs significantly suppressed the scratch-induced upregulation of vimentin, C3, NG2, and neurocan and downregulation of GFAP while also secreting higher levels of IL-10. Knockdown of IL-10 in aOECs using shRNA lentivirus reversed this suppression, leading to increased expression of vimentin, C3, NG2, and neurocan and decreased expression of GFAP. Notably, these protein changes were spatially restricted within the scratch zone. Collectively, these findings demonstrate that the in vitro MS injury model can mimic the inhibitory microenvironment of SCI and that aOECs can effectively attenuate astrocyte polarization to the A1 phenotype and reduce deposition of CSPGs through IL-10 secretion, thereby providing the regulatory mechanistic insight into glial scar formation after SCI.