Sir, In a recent Brain paper by Scott and Ramer (2010), they provided intriguing evidence that p75 neurotrophin receptor deletion caused enhanced axonal regeneration in a mouse model of dorsal rhizotomy. They also reported improved functional recovery in p75 knockout mice and co-culture studies, suggesting that p75 receptor expressed on Schwann cells is an inhibitive factor for neurite outgrowt...

Axonal regeneration does not occur easily after an adult central nervous system (CNS) injury. Various attempts have partially succeeded in promoting axonal regeneration after the spinal cord injury (SCI). Interestingly, several recent therapeutic concepts have emerged from or been tightly linked to the researches on brain development. In a developing brain, remarkable and dynamic axonal elongat...

Peripheral axons of dorsal root ganglion (DRG) neurons, but not their central axons in the dorsal columns, regenerate after injury. However, if the neurons are conditioned by a peripheral nerve injury into an actively growing state, the rate of peripheral axonal growth is accelerated and the injured central axons begin to regenerate. The growth-promoting effects of conditioning injuries have tw...

Spinal cord injury (SCI) is a debilitating disease which leads to progressive functional damages. Because of limited axonal regeneration in the central nervous system, there is no or little recovery expected in the patients. Different cellular and molecular approaches were investigated in SCI animal models. Cellular transplantation of stem cells can potentially replace damaged tissue and provid...

Optic nerve (ON) injury in adult mammals causes retinal ganglion cell (RGC) death and subsequent visual loss. Recovery of vision requires both rescuing axotomized RGCs and inducing their axonal regeneration. Axotomized RGCs are significantly rescued by overexpression of bcl-2, an anti-apoptotic gene. However, whether bcl-2 affects axonal regeneration is controversial. In neonatal bcl-2 transgen...

In larval lamprey, with increasing recovery times after a transection of the rostral spinal cord, there is a gradual recovery of locomotor behavior, and descending brain neurons regenerate their axons for progressively greater distances below the transection site. In the present study, spinal cord "conditioning lesions" (i.e., transections) were performed in the spinal cord at 30% body length (...

Axonal regeneration is enhanced by the prior ;conditioning' of peripheral nerve lesions. Here we show that Xenopus dorsal root ganglia (DRG) with attached peripheral nerves (PN-DRG) can be conditioned in vitro, thereafter showing enhanced neurotrophin-induced axonal growth similar to preparations conditioned by axotomy in vivo. Actinomycin D inhibits axonal outgrowth from freshly dissected PN-D...