Generating Retinal Injury Models in Xenopus Tadpoles

My lab works on retinal regeneration. We are using the Xenopus frog as a model system. This amphibian is indeed quite fascinating because unlike mammals, like us, it can regenerate its retina very efficiently in case of injury.

And we are studying the underlying mechanism because, in the future, it could be useful to trigger retinal regeneration in human patients afflicted with retinal neurodegenerative diseases. We have recently discovered that in addition to stem cells in the periphery of the retina and the retinal pigmented epithelium, neuroglial cells can also be recruited for retinal regeneration in case of injury. And so we are now studying the links between neuroinflammation and the regenerative capacity of these cells.

Indeed, it seems that the neuroinflammatory niche is a key player in the modulation of the regeneration of the retina. To study the cellular and molecular mechanisms involved in retinal regeneration, we developed several retinal injury paradigms in Xenopus. The first is a mechanical retinal injury.

The second is a transgenic line allowing for nitroreductase-mediated photoreceptor conditional ablation. The third is a retinitis pigmentosa model based on CRISPR/Cas9-mediated rhodopsin knockout, and, to finish, a cytotoxic model driven by intraocular injection of cobalt chloride or CoCl2. My host laboratory has showed that although Xenopus can regenerate its retina, the efficiency is highly variable and depends on the stages of the tadpole or on species, Xenopus laevis or tropicalis.

This makes Xenopus a fantastic model for illustrating the molecular mechanisms that trigger or limit retinal regeneration.