Abstract
Purpose:
The aim of this study was the in vivo examination of the mouse subbasal nerve fibre plexus (SBP) during regeneration process. Particularly, investigations addressed the regeneration capabilities of the injured SBP, and the influence of local ciliary neurotrophic factor (CNTF) application on the regeneration process. We have created a simple yet effective and well-tolerated injury model designed to influence a distinct corneal nerve area.
Methods:
Twelve-week-old BALB/c mice were included in this study. A circular incision through corneal epithelium and anterior stroma was generated with a custom-made guided trephine system to cut the nerves in SBP. The surgery was performed unilaterally. Animals were subdivided in 2 groups, one of them becoming CNTF eye drops 3 times daily. In vivo confocal laser scanning microscopy (Heidelberg Retina Tomograph/Rostock Cornea Module) was used to characterize the SBP before and up to 8 weeks after surgery. Nerve fibre density (NFD) was determined with the semi-automatic nerve tracing program NeuronJ.
Results:
NFD was reduced in both groups 24 hours after circular corneal incision. The regeneration of subbasal nerve fibres was based on sprouting out of stromal nerves within the cut and on regrowth of subbasal nerves over the scar from outside the cut. The statistically significant NFD reduction was observed for up to 3 weeks postoperatively in both groups, with and without CNTF, when compared to intact controls. The neuroprotective influence of CNTF eye drops was observed as early as 1 week after injury. At that time point the CNTF group displayed 38.39 % of baseline NFD, compared with only 13.02% in the group without CNTF. The difference between both groups remained significant for up to 4 weeks postoperatively. Eight week postoperatively NFD displayed 92.49% and 88.65% of baseline in the groups with and without CNTF-treatment, respectively.
Conclusions:
Uneventful healing of SBP could be demonstrated after surgical dissection in BALB/c murine corneas. The regeneration process was significantly accelerated by topical application of CNTF.
Keywords: 480 cornea: basic science •
765 wound healing