During the recovery phase of ischemic stroke, one of the major barriers for the spontaneous neuronal axon regeneration is the formation of astrogliosis and glial scar, and targeting astrogliosis becomes a therapeutic strategy for ischemic stroke. However, the mechanism regulating the process of scar components after ischemia still remains poorly understood. The aim of this study was to observe the role of RIP1 kinase (RIP1K), the key regulator of necroptosis (programmed necrosis) in the brain functional recovery after ischemic stroke and in the ischemic stroke-induced astrogliosis and glial scar formation in both
in vitro
and
in vivo
glial scar models. The glial scar formation model
in vitro
or
in vivo
was established by using primary cultured astrocyte subjected to 6 hours of oxygen-glucose deprivation (OGD) following 12 hours or 24 hours reperfusion, or by 90 min of transient middle cerebral artery occlusion (tMCAO) and reperfusion in rats. Western blotting analysis and immunohistochemical assay showed that knockdown of RIP1K by lentivirally-delivered shRNAs against RIP1K (shRNA RIP1K) could decrease several protein levels of glial scar markers such as glial fibillary acidic protein (GFAP), neurocan and phosphacan both in
in vitro
and
in vivo
glial scar models. Furthermore, western blotting analysis showed that knockdown of RIP1K reduced the protein levels of VEGF-D receptor 3 in
in vitro
glial scar models. In addition, knockdown of RIP1K also notably reduced the shrinking volume and ameliorated the behavioral symptoms in the recovery phase of rats after tMCAO. And immunocytochemistry assay demonstrated that RIP1K knockdown promoted the neuronal axonal generation in a neuron and astrocyte co-culture system. Our data indicates that RIP1K might play an important role in the formation of glial scar after ischemic stroke via promoting the function of VEGF-D receptor 3 in astrocytes.
Demyelination secondary to chronic nerve compression injury alters Schmidt-Lanterman incisures
