Assistant Professor Yuji Takihara of the University of Fukui and Professor Junichi Nabekura of the National Institute for Physiological Sciences have succeeded in taking a live video of the inside of the process (axon) of the optic nerve cell.This is the first time in the world that a video of a mammalian nerve axon has been recorded without dissection.This took evidence that mitochondrial transport was stopped in the optic nerve of mice with glaucoma.
Glaucoma is a disease in which the optic nerve is damaged and the visible range becomes narrower.It is the most common cause of blindness in Japanese and difficult to treat.It is thought that the cause is that the pressure inside the eyeball increases, and the pressure stops the transport of nutrients and organelles that flow through the axons.This transporting action within the axon is called axon flow, and if the stop of axon flow can be observed before glaucoma progresses, treatment can be started quickly.
In the axon, we observed the largest mitochondria as an object carried by the axon flow.This is because it is an organ that produces the energy required for cells to work, and it is known that mitochondrial function is inhibited before the optic nerve dies in glaucoma.By observing these mitochondria with a device called a two-photon laser microscope, we took a video of the mitochondria carried in each nerve axon.It was also found that in aged mice, areas without mitochondria expanded in axons and mitochondria themselves became shorter.This is consistent with clinical data that glaucoma is more likely to occur in older people.
In the future, we aim to utilize this technology for the treatment of glaucoma.Currently, treatment that promotes axonal flow by lowering the intraocular pressure with drugs or surgery is common, but how much the intraocular pressure should be lowered depends on the patient.Currently, the appropriate intraocular pressure cannot be known without looking at the course after treatment, but it can be expected that this method can be used to determine whether the intraocular pressure at that moment is appropriate.
Source:[National Institute for Physiological Sciences] Glaucoma and age-related changes revealed by live images of optic nerve axon flow