In vivo uptake and retrograde transport of the Rabies PV-pseudotyped lentiviral vector. A total of 2.5 × 104 TU in a volume of 2 μl were injected into the crushed sciatic nerve of rats. Animals were euthanized after 4 weeks. An X-gal staining kit was used to detect cells expressing the transgene. Eosin was used for counter-staining. While all the vectors mediated some kind of retrograde transport to DRGs, β-Gal transgene expression could only be detected in motor neurons of the spinal cord (arrows) of animals injected with the Rabies PV-pseudotyped vector. Scale bars = 50 μm (A), 1 mm (A').