Abstract
Purpose :
Newts have a remarkable capacity to regenerate multiple tissues throughout their entire adult life. Lens regeneration is especially fascinating as the regenerated lens originates from a completely different tissue through reprogramming of the iris pigmented epithelium. This process has never before been visualized in real time. Furthermore, damage caused by tissue processing and a lack of antibodies to detect structures in the newt eye have left gaps in our knowledge of the lens regeneration process. Our goal was to use optical coherence tomography (OCT) to characterize structural changes within the same newt during the entire lens regeneration process.
Methods :
The lens was surgically removed from a single adult Notophthalmus viridescens, red spotted newt, and OCT images acquired over the course of 43 days. At the 43rd day, the newt eye was collected and processed for histology. All OCT images were acquired around 800nm with ~8µm lateral resolution and ~3µm axial resolution. To facilitate imaging, the newt was sedated with 0.1% MS222 in APBS.
Results :
By 14 days post-lentectomy (dpl) the regenerating lens vesicle was detectable by OCT. In addition, multiple blood vessels can be seen in the iris. Throughout the remaining time points the growing lens vesicle can be observed, including the formation of an anterior lens epithelium. Unexpectedly, by day 32 dpl zonular fibers attaching to the regenerated lens were also observed.
Conclusions :
This is the 1st report for in vivo imaging of newt lens regeneration in real time using OCT. Observing the developing lens vesicle in as little as two weeks after lentectomy highlights the power of OCT for these studies. Furthermore, how and when zonular fibers attach to the regenerating lens has never been studied but is now possible because of OCT. Current and ongoing work includes validating OCT results by traditional histology in a larger cohort of animals.
This is a 2020 ARVO Annual Meeting abstract.