Astrocyte scar formation aids central nervous system axon regeneration

Transected axons fail to regrow in the mature central nervous system. Astrocytic scars are widely regarded as causal in this failure. Here, using three genetically targeted loss-of-function manipulations in adult mice, we show that preventing astrocyte scar formation, attenuating scar-forming astrocytes, or ablating chronic astrocytic scars all failed to result in spontaneous regrowth of transected corticospinal, sensory or serotonergic axons through severe spinal cord injury (SCI) lesions. By contrast, sustained local delivery via hydrogel depots of required axon-specific growth factors not present in SCI lesions, plus growth-activating priming injuries, stimulated robust, laminin-dependent sensory axon regrowth past scar-forming astrocytes and inhibitory molecules in SCI lesions. Preventing astrocytic scar formation significantly reduced this stimulated axon regrowth. RNA sequencing revealed that astrocytes and non-astrocyte cells in SCI lesions express multiple axon-growth-supporting molecules. Our findings show that contrary to the prevailing dogma, astrocyte scar formation aids rather than prevents central nervous system axon regeneration

Nyane: The Reemergence of Black Resistant Masculinity through Sport

The purpose of this paper is to examine the origins and social construction of Black masculinity through sport and athletic competition, beginning with an examination of the role of sport on the African continent and contrasting that with its role within the system of chattel slavery in the Americas. Under this system of brutality and oppression emerged two different types of masculinity in relation to athletics: resistant masculinity used athletics to retain cultural memo- ries and reaffirm identity, while marginalized masculinity used athletics to entertain slave owners to survive enslavement and oppression. This paper argues that resistant masculinity encouraged enslaved Africans and their descendants to use sport as a tool of resistance and reaffir- mation of identity. This paper connects this legacy with the actions of athletes and other men of African descent using both historical and contemporary frames of reference