THE USE OF THE THY-1-YFP-H TRANSGENIC MOUSE STRAIN IN STUDIES OF PERIPHERAL NERVE INJURY

The aim of these studies was to utilise the thy-1-YFP-H transgenic mouse strain to investigate the effects of exogenous agents and the use of nerve conduits on peripheral nerve repair, while developing analysis methods to quantify nerve regeneration in this strain. Using a thy-1-YFP-H mouse common fibular nerve repair model, two potential nerve regeneration enhancing agents [mannose-6-phosphate and EC23] and four conduit designs were assessed.
The outcomes of the experiments were measured by analysing whole mount images of the repaired nerves and comparing: axon numbers across the repairs, the proportion of unique axons reaching set distances within the repairs, and the disruption of axons as they entered the repairs. Of the two potential nerve regeneration enhancing agents [administered by pre-soaking the graft tissue and injections into the surrounding tissue] mannose-6-phosphate was shown to significantly reduce the disruption of axons entering the graft, which tied in with results of previous studies on mannose-6-phosphate. EC23 did not appear to have any significant effect upon nerve regeneration, displaying similar results to vehicle treated grafts. Within the conduit studies, both micro-stereolithography produced hollow conduit designs proved successful at enabling regeneration across a short nerve defect - with quantitative results similar to graft repairs - however, axon organisation within those repairs was greatly reduced. The other two conduit designs [aligned fibre filled and hollow nylon-12] were less successful, with limited regeneration occurring across the nerve defect.
Through the results of these studies the usefulness of the thy-1-YFP-H transgenic mouse strain in assessing nerve regeneration has been further established. The ability to trace the fate of individual axons through repairs reveals much information that was previously not possible or very difficult to obtain. In addition, the ability to obtain results in only 2-3 weeks makes this model ideal for obtaining useful data quickly for pilot studies.