Developing a trans-multisynaptic tracer to map the neural circuit of recovered sciatic nerve after treatment with nerve growth factor.

Nerve growth factor (NGF) has been shown to support the survival and differentiation of neurons. In this study, we first developed a retrograde trans-multisynaptic tracer PRV580 expressing the mCherry fluorescent protein based on pseudorabies virus Bartha strain to map the neural circuit of sciatic nerve. Secondly, the newly developed PRV580 was used to map the neural circuit of the recovering sciatic nerve upon treatment with NGF. Our results showed that red signals from PRV580 were observed in various brain regions. Among these regions, many areas of the pyramidal system and the extra-pyramidal system had been mapped, accounting for as much as 56.8 % of the total inputs. Furthermore, we found that NGF could significantly increase the ratio of total input (29.05 %) compared to PBS (3.65 %), indicating that NGF indeed can aid in the repair of injured sciatic nerve. These findings indicated that NGF has therapeutic ability for the treatment of peripheral nerve injuries and virus-based tracers can be used to monitor the recovery.