Background Efforts in cell replacement therapy for Huntington’s disease (HD) are hindered by uncertainty of graft fate after transplantation. Current cell tracking methods fall short to either: 1) Detect labelled transplanted cells, or 2) Differentiate between live and dead cells, or 3) Provide long term tracking of growing grafts. Bioluminescence imaging (BLI) addresses these problems and could provide a cheaper, more reliable and less inconvenient alternative to currently used intracerebral cell tracking techniques.

Aim We aimed to describe methods for long term tracking of transplanted Human Foetal Cells (HFC) using BLI in a HD rat model.

Methods In-vitro: We have developed protocols to transduce Human Embryonic Kidney cells, Medium Spiny Neuron Progenitors and eventually HFCs with a lentivirus carrying a firefly luciferase gene.

In-vivo: Using quinolinic acid lesioned adult female Sprague-Dawley rats as a HD model, 4 animals underwent transduced-cells transplantation followed immediately by BLI using intracerebral (IC) luciferin injection. These animals had pre and post-operative MRI for comparison. Five animals underwent BLI with IC luciferin at 12 weeks. Eight animals underwent acute BLI after transplantation using intraperitoneal (IP) Luciferin alternatives, namely: AkaLumin, D-Luciferin, D-Luciferin packaged in a nano vector and InfraLuciferin.

Results In-vitro: All tested cell types were reliably transduced with a viral vector to express engineered luciferase. HFC viability inversely correlated with duration of incubation with the virus.

In-vivo: HFC grafts were detected using BLI acutely and at 12 weeks after transplantation. D-Luciferin packaged in a nano vector showed promising results after IP injection, however signal is considerably weaker than IC injection.

Conclusion BLI reliably and conveniently tracks transplanted HFC in small animals. This technique has great potentials in studying graft fate in terms of localization, viability, growth and integration.