Regeneration technology allows blind mice to re-open

researchers have blasted new photoresponsive cells on the retina of mice that convert light into electrical signals. Photo Credit Nathan Devery/Science
some cells in the eyes can repair damage caused by visually impaired diseases. But so far, scientists have not succeeded in making them work. Now, a team of researchers claims to have encouraged the cells -- known as "Miller glial cells" -- to regenerate a photoresortor cell in the eyes of mice. According to the scientists' findings, published August 15 in the British journal
, the new cells can detect incoming light and network it with other cells in the eye to send signals to the brain, a potential step in reversing certain genetic eye diseases and injuries that offer new hope for treating blinding diseases such as retinal pigmentation. But some are skeptical, saying the signals may have come from existing photoreceptic cells rather than newly generated cells.
no one wants this to be true more than I do, but I have serious concerns about this study," said Seth Blackshaw, a neuroscientist at Johns Hopkins University School of Medicine in Baltimore, Maryland. Zebrafish have a self-healing function in their retina, and when the retina is damaged, their "Miller glial cells" regenerate nerve cells in the retina, while mammalian cells do not have a similar regenerative function, said Chen Bo, author of the
study and professor of neurology and ophthalmology at the Icahn School of Medicine in Mount Sinai, USA. Although the scientific community has been able to activate mammalian "Miller glial cells" by damaging the retina, this method is more damaging to the retina and is not conducive to the restoration of vision.
, the researchers used gene transfer in mouse experiments to cause "Miller glial cells" to divide and develop into light-sensing rod cells. Newly developed rod cells are structurally no different from natural rod cells and form a synaptic structure that allows them to communicate with other nerve cells in the retina. Experiments have shown that this method allows congenescingly blind mice to recover.
study was funded by the National Eye Institute. This is the first time scientists have re-edited "Miller glial cells" into functional rod cells in the mammalian retina, said Thomas Greenwell, director of the institute's retinal neuroscience program. The rod cells allow people to see things in dark light conditions and may help protect the cone cells, which are responsible for distinguishing colors and increasing visual sensitivity.
chen bo said they plan to use in-body culture experiments to see if the new method can be used in human retinal tissue.
"No one can make a cell like a light receptor like they do, " he says. Deborah Otteson, a cell and developmental neurobiologist at the University of Houston's School of Ophthalmology in Texas, said. But she noted that even in mice that regenerate the most new retina cells, the density was only 0.2 percent of that of healthy mice. As a result, the treated mice were able to detect light, but they could not recognize shapes or objects.
"they've cracked the first part of the problem, and now the problem is to zoom it in." Otteson said. If researchers can get "Miller glial cells" to produce more photoresist cells, she said, this approach could one day restore some vision to those who lose their retinal cells due to retinal shedding or genetically disordered retinitis.
Maureen McCall, a neurobiologist at the University of Louisville in Kentucky, called the work a "big step forward" in restoring the optician cells, but stressed that the team still needs to prove that the development and function of the rod cells are normal in the sick eye -- where retinal cells may not connect and interact properly.
However, Blackshaw sees another explanation for the new findings: In blind mice, existing rod cells were repaired during surgery, either because they accepted the corrective genes carried by the virus, or because "Miller glial cells" shared the correct genes with them. In both cases, the brain's visual signals do not come from newly generated rod cells, but from the function of existing sensory cells. He said the study ignored chemical labeling techniques that could prove that any functional rod-like cells come from "Miller glial cells."
chen bo said he and his team did such a marking experiment -- although not described in the paper, and they have thoroughly demonstrated the origin of the new rod cells in several other ways. He also cited a control group experiment in which the team transferred the corrected gene to "Miller glial cells" without reprogramming. In this case, there are no visual signals in the brain, which means that the existing rod cells are not restored. (Source: Zhao Xixi, China Science Daily)