Transplants help night-blind mice: injecting light-gathering rod cells restores vision in rodents.
The farmer's wife in the nursery rhyme "Three Blind Mice" may need a different hunting strategy. Thanks to cell transplants, some formerly night-blind mice can see in the dark, perhaps even well enough to evade a swinging carving knife.
Light-gathering nerve cells called rods injected into the retinas of night-blind mice integrated into the brain's visual system and restored sight, Robin Ali of the University College London Institute of Ophthalmology and colleagues report online April 18 in Nature. The finding gives hope that cell transplants may reverse damage to the brain and eyes caused by degenerative diseases and help heal spinal cord injuries.
Other researchers have tried unsuccessfully to repair damaged retinas with stem cell transplants, says Christian Schmeer, a neurologist at the University Hospital Jena in Germany. The new study is the first to demonstrate that transplanted nerve cells can restore function.
Ali's group transplanted immature rod cells from newborn mice into the retinas of night-blind adult mice. The researchers were able to coax about 26,000 rod cells, which work in dim conditions, to become incorporated into each retina.
Other retina cells called cones sense bright light. Humans rely more on cones than nocturnal mice do; so far Ali's team has had no luck transplanting cones.
Other problems also remain to be solved before researchers can even consider trying cell transplants in human eyes, Ali says. The mice in the study all had healthy retinas, so Ali wants to see if the technique will work as well in diseased eyes. Getting a good source of cells to transplant is another problem. Ali plans to try implanting rod cell precursors made from stem cells.