Long-Term Extensive Ectopic Hair Growth on the Spinal Cord of Mice from Transplanted Whisker Follicles
Hair follicle stem cells from ND-GFP mice were transplanted into the gap region of severed sciatic nerves of nude mice.
The transplanted stem cells enhanced the rate of nerve regeneration and the restoration of nerve function. The ND-GFP cells differentiated mostly into Schwann (glial) cells, which supported neuron regrowth.
Nestin-expressing hair follicle stem cells were subsequently transplanted to the injured spinal cord of nude mice.
Most of the transplanted cells also differentiated into Schwann cells which facilitated repair of the severed spinal cord.
The rejoined spinal cord resulted in extensive hind-limb locomotor performance recovery.
We have previously demonstrated that hair follicles contain nestin-expressing pluripotent stem cells that can effect nerve and spinal cord repair upon transplantation.
In the present study, isolated whisker follicles from nestin-driven green fluorescent protein (ND-GFP) mice were histocultured on Gelfoam for 3 weeks for the purpose of transplantation to the spinal cord to heal an induced injury.
The hair shaft was cut off from Gelfoam-histocultured whisker follicles, and the remaining part of the whisker follicles containing GFP-nestin expressing pluripotent stem cells were transplanted into the injured spinal cord of nude mice, along with the Gelfoam.
After 90 days, the mice were sacrificed and the spinal cord lesion was observed to have healed. ND-GFP expression was intense at the healed area of the spinal cord, as observed by fluorescence microscopy, demonstrating that the hair follicle stem cells were involved in healing the spinal cord.
Unexpectedly, the transplanted whisker follicles sprouted out remarkably long hair shafts in the spinal cord during the 90 days after transplantation of Gelfoam whisker histocultures to the injured spine.
The pigmented hair fibers, grown from the transplanted whisker histocultures, curved and enclosed the spinal cord.
The unanticipated results demonstrate the great potential of hair growth after transplantation of Gelfoam hair follicle histocultures, even at an ectopic site.