Damaged optic nerves – which run from the eye to the brain – have been regrown for the first time by scientists working with mice.
The researchers believe the technique might one day restore sight to people whose optic nerves have been damaged by injury or glaucoma. It could even help regenerate other nerves in the body, they say.
A team led by Dong Feng Chen, at the Schepens Eye Research Institute in Boston, US, combined two genetic modifications to regrow the optic nerve after it was damaged.
First they turned on a gene called BCL-2, which promotes growth and regeneration of the optic nerve in young mice. This gene is normally turned off shortly before birth. They then bred those animals with other mice carrying genetic mutations that reduce scar tissue in injured nerves.
The researchers crushed the optic nerves shortly after birth, and found that in young mice – less than 14 days old – between 40% and 70% of the injured optic nerve fibres regrew to reach their target destinations in the brain. No regrowth was seen in injured mice without the genetic modifications.