Acta Neurochir (Wien) (2007) 149: 407–414 DOI 10.1007/s00701-007-1121-5 Printed in The Netherlands Experimental Research Implantation of pure cultured olfactory ensheathing cells in an animal model of parkinsonism D. Dewar, D. Bentley, and S. C. Barnett Division of Clinical Neuroscience, Wellcome Surgical Institute, Beatson Labs, Garscube Estate, University of Glasgow, Glasgow, UK Received June 30, 2006; accepted February 5, 2007; published online March 28, 2007 # Springer-Verlag 2007 Summary Background. Implantation of neural cells has been proposed as a therapeutic strategy for repairing the in- jured or diseased brain. In the present study we have examined the potential of olfactory ensheathing cells (OEC) to promote brain repair after surgical implanta- tion in a rodent model of parkinsonism. Methods. Neonatal OECs were implanted in the stria- tum after a 6-hydroxydopamine lesion of the ipsilateral substantia nigra. Amphetamine-induced rotational asym- metry scores were determined 48 hours before and 4, 6 and 8 weeks after OEC implantation. The density of immunostaining for tyrosine hydroxylase and synapto- physin in the striatum and the number of tyrosine hy- droxylase-positive cells remaining in the substantia nigra were also determined. Results. Rotational asymmetry scores were similar in OEC-implanted and vehicle-treated groups at all time points examined, and at each time were similar to those observed prior to implantation. Levels of striatal tyro- sine-hydroxylase and synaptophysin immunoreactivity were similar in OEC- and vehicle-treated groups. The number of tyrosine-hydroxylase-positive cells in the substantia nigra was similar in both groups indicating that severity of the lesion was similar. Visualisation of GFP-labelled OECs one week after implantation in a sep- arate group of animals revealed the cells to be located in the area immediately surrounding the needle tract. Conclusion. This study demonstrates that implantation of OECs alone is not sufficient to promote tissue repair and functional recovery in a rodent model of parkinsonism. The results add to a growing number of studies that pro- pose a caveat for the use of pure OECs as a neurosurgical strategy for the treatment of brain disease or injury. Keywords: Olfactory ensheathing cells; 6-hydroxydo- pamine; striatum; brain injury; synaptogenesis. Introduction Neurosurgical implantation of neural cells into the injured or diseased CNS has been proposed as a potential therapeutic strategy. Many important issues surrounding such an approach still remain to be investigated in ani- mal studies before it can be translated into effective clinical use. These include site of implantation relative to that of the primary pathology and the type of cell, or combination of cells, that will effect maximum beneficial outcome. Two alterative cell implantation strategies can be considered. Firstly, replacement of cells that have succumbed to injury or disease, or secondly, implantation of cells into surviving tissue to enhance reorganisation, plasticity and regenera- tive processes within those regions [6]. A range of different cell candidates are currently being evaluated for their ability to improve outcome in various diseases and following injury [18, 22, 23]. One candi- date is the olfactory ensheathing cell (OEC). A crucial aspect of OECs if they are to be developed therapeu- tically is the ability to derive them autologously, thus obviating the requirement for immunosupression if exogenously-derived cells are used. Our group has al- ready demonstrated that OECs neurosurgically removed