Abstract Regulatory T cells (Tregs) are found to participate in the pathogenesis of cerebral ischemic stroke. Exosomes derived from Tregs (Treg-Exos) were found to mediate the mechanism of Tregs’ roles under various physiological and pathological conditions. But the roles of Treg-Exos in cerebral ischemic stroke are still unclear. Here, we explored the protective effects of Treg-Exos against microglial injury in response to oxygen-glucose deprivation/reperfusion (OGD/R) exposure. The results showed that Tregs-Exos relieved OGD/R-caused increases in LDH release and caspase-3 activity in BV-2 cells. The decreased cell viability and increased percentage of TUNEL-positive cells in OGD/R-exposed BV-2 cells were attenuated by Tregs-Exos treatment. Tregs-Exos also suppressed OGD/R-induced increase in production of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 in BV-2 microglia. Furthermore, Tregs-Exos induced the expression levels of phosphorylated phosphatidylinositol-3-kinase (p-PI3K) and phosphorylated protein kinase B (p-Akt) in BV-2 microglia under the challenge of OGD/R. Inhibition of the PI3K/Akt signaling by LY294002 partly reversed the effects of Tregs-Exos on cell apoptosis and inflammation in OGD/R-exposed BV-2 microglia. These results indicated that Tregs-Exos exerted protective effects against the OGD/R-caused injury of BV-2 microglia by activating the PI3K/Akt signaling.

A novel hydroxyl-terminated polymer HPMS-APE was synthesized by introducing allyl polyethylene oxide (APE) into hydrogen-terminated polydimethylsiloxane (HPMS) backbone by hydrosilylation reaction. A series of hyperbranched polyurethane elastomers (HBPUs) based on HMPS-APE and polypropylene glycol (PPG) mixed soft segments were successfully synthesized with trimethylolpropane (TMP) as a chain extender. The effect of HPMS-APE segments content on enhanced properties of HBPUs were characterized by Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), atomic force microscopy (AFM), thermogravimetric analysis (TGA), mechanical testing and water absorption. It was found that incorporating HPMS-APE in polyurethanes made substantial changes in their morphology, thermal properties, mechanical properties and water absorption. When 5 wt% HPMS-APE was incorporated in HBPUs, the extent of microphase separation between hard and soft segments was the best, resulting in polyurethanes without significant compromise in tensile strength and elasticity. Furthermore, HBPUs derived from HPMS-APE presented excellent thermal stability and unique water resistance.