Proangiogenic functions of osteopontin-derived synthetic peptide RSKSKKFRR in endothelial cells and postischemic brain

The aim of this study was to investigate the potential therapeutic effects of a newly discovered osteopontin-derived synthetic peptide "RSKKFRR" in a rat model of ischemic stroke.A total of 24 male SD rats were randomly divided into three groups. The model of ischemic stroke was made up of the middle cerebral artery occlusion (MACO). The rats were divided into sham operation group (Sham), control group (MACO + PBS) and treatment group (MACO + OPNpt9), eight rats in each group. In the control group and the treatment group, PBS or OPNpt9 was injected into the nasal cavity after MACO once a day, and the area of new blood vessels and the recovery of nerve function were observed 14 days later. Whether the proliferation, migration and tube formation of HUVECs were promoted by OPNpt9 was tested. The expression levels of related proangiogenic factors were also detected.OPNpt9 was found to contribute to cerebral microvascular remodeling and neurological improvement in ischemic rats while promoting endothelial cell migration, proliferation and tube formation in vitro. These effects were mediated by activation of the p-ERK/MMP-9/VEGF pathway.In conclusion, OPNpt9 promotes angiogenesis and neurological recovery after ischemic stroke.