The thy-1-YFP-H transgenic mouse strain is potentially useful for analysing nerve regeneration in experimental studies. A subset of nerve cells within the mice express yellow fluorescent protein along the entire length of their axons, allowing visual analysis of the regenerating axons to be performed.
Here we report the use of this strain in two studies of nerve regeneration; the first assessed the effects of a potential anti-scarring agent, mannose-6-phosphate, and the second assessed the ability of hollow poly(ethylene-glycol) nerve guide conduits (NGCs) to support nerve regeneration.
Method: Under anaesthesia the common fibular nerve in thy-1-YFP-H mice was exposed, sectioned and a gap created. In the mannose-6-phosphate study, this was repaired using a graft from a wild-type littermate soaked for 30mins in mannose-6-phosphate or vehicle. In the NGC study nerves were repaired using a NGC or wild-type graft. After recovery (2-weeks for mannose-6-phosphate study and 3-weeks for NGC study) mice were re-anaesthetised and the nerve fixed in situ with 4% formaldehyde. The repaired nerve was excised, mounted whole on a slide and coverslipped.
Result: In the mannose-6-phosphate study no significant differences were found between treated and untreated repairs in terms of overall and unique regenerating axon numbers. However, axonal disruption was significantly less in mannose-6-phosphate treated animals (p<0.05).
In the NGC study no significant quantitative differences were found between NGC and graft repairs, however, axons in NGC repairs displayed less organisation.
Conclusion: The visual analysis made possible by using the thy-1-YFP-H mouse strain has provided us with useful insights into axonal disruption and organisation at sites of nerve repair and regeneration. These insights would not have been possible using traditional analysis methods.