RNA interference-mediated silencing of S100B improves nerve function recovery and inhibits hippocampal cell apoptosis in rat models of ischemic stroke

Abstract

Ischemic stroke is the leading cause of worldwide mortality and long-term disability in adults. This study aims to explore the effects of RNA interference (RNAi)-mediated silencing of the S100B gene on nerve function recovery and morphological changes of hippocampus cells in rat models with ischemic stroke. Sixty Wistar rats were assigned into different group. S100B and Caspase 3 mRNA and protein expressions were evaluated by RT-qPCR and Western blotting. Positive rate of S100B, NeuN, and MAP2 expressions were detected by immunohistochemistry (IHC). Water content, malondialdehyde (MDA) levels, and superoxide dismutase (SOD) activity in brain tissues were measured. Enzyme-linked immunosorbent assay (ELISA) was employed to detect serum levels of TNF-α and IL-1β. A neurological severity score (NSS) was used to test nerve function. TUNEL assay was used to determine hippocampal cell apoptosis. Downregulation of S100B showed a lower number of S100B immune positive cells, but higher NeuN and MAP2-positive cells, increased SOD level, declined MDA level, prominently faster recovery of neurological function, decreased TRCS, TCTP, TCFP, and IE levels, an obvious increase in the number of survival neurons, a decrease in the number of apoptotic cells, notably decreased TNF-α and IL-1β contents, as well as infarct volume, an obvious decrease in positive hippocampal cell Caspase 3 expression and protein expressions of Caspase 3 and cleaved Caspase 3. This study provides data to suggest that RNAi-mediated silencing of S100B gene could improve the recovery of nerve function while inhibiting apoptosis of hippocampal cells in rats with ischemic stroke.