Abstract： LncRNA(long non-coding RNA)H19 is a transcript of the H19 gene that is expressed during embryogenesis.We previously discovered a role for circular IncRNA H19 in the onset and prognosis of cerebral ischemic stroke.In this study,we used serum from patients with ischemic stroke,and mouse and cell culture models to elucidate the roles of plasma and neuronal exosomes in the regulatory effect of IncRNA H19 on insulin-like growth factor-1 and its mechanism in ischemic stroke,using western blotting,quantitative real-time polymerase chain reaction,and enzyme-linked immunosorbent assays.Plasma exosomal IncRNA H19 was negatively associated with blood levels of insulin-like growth factor-1 in samples from patients with cerebral ischemic stroke.In a mouse model,levels of exosomal IncRNA H19 were positively correlated with plasma and cerebral IncRNA H19.In a cell co-culture model,we confirmed that IncRNA H19 was transported from neurons to astrocytes by exosomes to induce downregulation of insulin-like growth factor-1 through the H19/let-7a/insulin-like growth factor-1 receptor axis.This study provides the first evidence for the transportation of IncRNA H19 by exosomes and the relationship between IncRNA H19 and insulin-like growth factor-1.