Rh-IFN-alpha attenuates neuroinflammation and improves neurological function by inhibiting NF-kappa B through JAK1-STAT1/TRAF3 pathway in an experimental GMH rat model

摘要

Neuroinflammation occurs after germinal matrix hemorrhage (GMH) and induces secondary brain injury. Interferon-alpha (IFN-alpha) 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-alpha (rh-IFN-alpha) 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-alpha 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-alpha and phosphorylated IFNAR levels were increased after GMH. Administration of rh-IFN-alpha 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-kappa B, IL-6 and TNF-alpha. Specifically, knockdown of IFNAR, JAK1 and TRAF3 abolished the protective effects of rh-IFN-alpha. In conclusion, our findings demonstrated that rh-IFN-alpha treatment attenuated neuroinflammation, neurological deficits and hydrocephalus formation through inhibiting microglial activation after GMH, which might be mediated by IFNAR/JAK1-STAT1/TRAF3/NF-kappa B signaling pathway. Rh-IFN-alpha may be a promising therapeutic agent to attenuate brain injury via its anti-inflammatory effect.