Abstract
Neuroinflammation occurs after germinal matrix hemorrhage (GMH) and induces secondary brain injury. Interferon-α (IFN-α) has been shown to exert anti-inflammatory effects in infectious diseases via activating IFNAR and its downstream signaling. We aimed to investigate the anti-inflammatory effects of Recombinant human IFN-α (rh-IFN-α) and the underlying mechanisms in a rat GMH model. Two hundred and eighteen P7 rat pups of both sexes were subjected to GMH by an intraparenchymal injection of bacterial collagenase. Rh-IFN-α was administered intraperitoneally. Small interfering RNA (siRNA) of IFNAR, and siRNA of tumor necrosis factor receptor associated factor 3 (TRAF3) were administered through intracerebroventricular (i.c.v.) injections. JAK1 inhibitor ruxolitinib was given by oral lavage. Post-GMH evaluation included neurobehavioral function, Nissl staining, Western blot analysis, and immunofluorescence. Our results showed that endogenous IFN-α and phosphorylated IFNAR levels were increased after GMH. Administration of rh-IFN-α improved neurological functions, attenuated neuroinflammation, inhibited microglial activation, and ameliorated post-hemorrhagic hydrocephalus after GMH. These observations were concomitant with IFNAR activation, increased expression of phosphorylated JAK1, phosphorylated STAT1 and TRAF3, and decreased levels of phosphorylated NF-κB, IL-6 and TNF-α. Specifically, knockdown of IFNAR, JAK1 and TRAF3 abolished the protective effects of rh-IFN-α. In conclusion, our findings demonstrated that rh-IFN-α treatment attenuated neuroinflammation, neurological deficits and hydrocephalus formation through inhibiting microglial activation after GMH, which might be mediated by IFNAR/JAK1-STAT1/TRAF3/NF-κB signaling pathway. Rh-IFN-α may be a promising therapeutic agent to attenuate brain injury via its anti-inflammatory effect.