What's black and white and might help humans regenerate their eyes all over? The tiny zebra fish. While only a few centimeters long, the freshwater minnow native to the Himalayan region is capable of amazing feats of regeneration. When their hearts, brains, fins or eyes are damaged, they can regrow them—and it's that last ability that has scientists hooked.
A team of scientists at Vanderbilt University, led by biology professor James Patton, were initially interested in how retina regeneration is initiated in zebra fish. Previous studies have suggested that growth factors secreted by dying photoreceptors in the fish's eyes might start the process, but one of Patton's students got the idea to look at the neurotransmitter GABA, a chemical messenger in the brain that reduces neuron activity.
They found that blind fish given the stimulating drugs couldn't regenerate their retinas normally, while anther group of fish with lowered GABA levels began to regenerate their retinas. That suggested that it was, indeed, a lowered GABA concentration that helped initiate retinal regeneration.
"The zebra fish retina can be damaged to cause blindness, yet it only takes about three to four weeks before vision is restored," Patton said. "So I became even more intrigued as to why humans cannot regenerate damaged retinas and fish can. We hope to use the fish model to understand the factors and mechanisms regulating retina regeneration in the hope that we can apply lessons learned to humans."
The results of the study were published this month in Stem Cell Reports.