Objective:To explore the protective effect of zonisamide (ZNS) on oxygen-glucose deprivation (OGD) cell model of traumatic brain injury (TBI), and its underlying mechanism.Methods:Human neuroblastoma cells (SH-SY5Y) were cultured in vitro and divided into the control group, OGD group, and drug administration group (OGD+ZNS group) according to the random number table method. The OGD method was used to establish a TBI cell model. After modeling, the cell activity, the release of lactate dehydrogenase (LDH), and β-galactosidase staining were detected to evaluate cell function and senescence. Additionally, mitochondrial morphology and potential membrane changes were observed using Mito Tracker Red and JC-1 mitochondrial membrane potential staining. ATP concentration was measured, and protein was extracted from SH-SY5Y cells and then subjected to Western blot analysis to detect endoplasmic reticulum stress-related markers, including glucose-regulated protein 78 (GRP78), C/EBP homologous protein (CHOP), protein disulfide isomerase (PDI), and β-actin.Results:The OGD group had a significantly lower cell survival rate compared to the control group ( P<0.01), while the OGD+ZNS group had a significant higher cell survival rate than the OGD group ( P<0.01). The LDH release rate was significantly higher in the OGD group than in the control group ( P<0.01), while the OGD+ZNS group had a significant lower LDH release rate compared to the OGD group ( P<0.01). Moreover, the cell staining results indicated that compared to the control and OGD+ZNS groups, the cells in the OGD group exhibited significant damage and senescence with darker staining while the mitochondrial staining results demonstrated a significant reduction in mitochondrial linear junctions and decreased mitochondrial activity in the OGD group compared to the control and OGD+ZNS groups. Compared to the control and OGD+ZNS groups, the OGD group exhibited a significant reduction in mitochondrial staining red fluorescence, a significant increase in green fluorescence, and a significant decrease in mitochondrial membrane potential. The OGD group demonstrated a significant decrease in ATP concentration compared to the control group ( P<0.01), whereas the OGD+ZNS group exhibited a significant higher ATP concentration compared to the OGD group ( P<0.01). Western blot analysis revealed significant upregulation of GRP78, CHOP, and PDI in the OGD group compared to the control group (all P<0.05), while in the OGD+ZNS group, the expression levels of these proteins were significantly downregulated compared to the OGD group (all P<0.05). Conclusions:Zonisamide can protect OGD TBI cell model by preserving mitochondrial activity and inhibiting endoplasmic reticulum stress.