SURVIVAL AND FUNCTIONING OF PC12 CELLS FOLLOWING TRANSPLANTATION IN THE RAT STRIATUM

The transplantation of dopamine-producing cells into the mammalian CNS is an emerging treatment for PD, despite relatively poor survival of implanted tissue.. Survival and histomorphological changes of PC12 or other kind of neuronal cells implanted in experimental animals have been thoroughly addressed in several studies However, microdialysis in vivo studies on the functioning of implanted PC12 are restricted solely to the paper of Tresco et al (1). In this study, we implanted of one million of PC12 cells in the intact striatum of the rats. The implant was performed using a probe which allows us to collect also dialysates from the implanted cells, and for this reason it is left in situ; however, it allow us to collect dialysates only for few days after PC12 implant, owing to the reduction of microdialysis performance. Results of these preliminary experiments showed that 3 days after PC12 implant, a challenge infusion of the NO donor SIN-1 (5.mM) significantly increased dialysate concentrations of DA+3-methoxytyramine (67.5±8.7 nM), as compared with a challenge infusion in the intact striatum (29.4±5.7 nM). For long-term microdialysis monitoring, we used a microcarrierimplanting system, which consist in a 23G guide cannula inserted in the striatum, which allowed us to implant 30 µl of a concentrated PC12-Cytodex suspension (around 40 cells/microcarrier). In this system Cytodex 3 microcarriers enhance the survival in the absence of immunosuppression (2). The striatal microdialysis probe is thereafter inserted through the guide cannula (which was left in situ) at different days after the implant. Preliminary experiments showed that microcarrier-implanted PC12 were still functioning two weeks after the implant.