Morphological and Behavioral Drawbacks of Fetal Dopaminergic Grafts, Prelabeled with Phaseolus vulgaris Leucoagglutinin

• Published in: Experimental neurology Vol. 122; no. 2; pp. 260 - 272
• Main Authors: Dolleman-Van der Weel, M.J., Nijssen, A., Steinbusch, H.W.M.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.08.1993
• Subjects: Animals; Apomorphine; Behavior, Animal - drug effects; Brain - cytology; Brain - embryology; Brain - metabolism; Cell Survival - drug effects; Dopamine - metabolism; Embryo, Mammalian - metabolism; Fetal Tissue Transplantation; Male; Phytohemagglutinins - adverse effects; Phytohemagglutinins - pharmacokinetics; Rats; Rats, Wistar; Stereotyped Behavior - drug effects
• ISSN: 0014-4886; 1090-2430
• DOI: 10.1006/exnr.1993.1126

The anterograde tracer Phaseolus vulgaris Leucoagglutinin (Pha-L) was tested as a fetal cell marker in short-term labeling of a fetal dopaminergic cell suspension and in long-term surviving grafts in vivo. As a model we used the grafting of fetal dopaminergic cells into the denervated caudate putamen of the rat. Short-term labeling revealed that the viability of the fetal cells was not affected by the Pha-L incubation within the 4 h of the test period. Yet, n subtle difference was noticed in the morphological development of the fetal neurons. Whereas many dopaminergic cells in the control suspension developed from an initially round soma to a more triangular or bipolar one, Pha-L-incubated cells maintained their round appearance. Moreover, cells with developing neurites were commonly noted in the control suspension, but were absent after incubation with Pha-L. Long-term effects of Pha-L were studied in three groups of unilaterally 6-hydroxydopamine-lesioned rats, which all received an injection of a fetal dopaminergic cell suspension in the denervated caudate putamen. The first group (T-Pha-L) received dopaminergic cells, prelabeled with Pha-L. The second group (T-saline) received cells incubated with vehicle (saline). The third group (T) received only dissociated cells. Eight weeks after the implantation the morphological analysis showed a minor Pha-L-immunoreactivity inside the labeled grafts. We detected Pha-L-positive fiber particles as well as weakly Pha-L-positive spots, presumably cell bodies. Pha-L-labeled grafts were significantly decreased in graft volume and contained markedly less dopamine-immunoreactive (DA i) cells than the control grafts of groups T-saline and T. The ratio DA i cell type I (cell with ⩽3 processes)/DA i cell type II (cell with ⩾4 processes) was approximately 8 in the control groups and 3 in group T-Pha-L. This suggests primarily a toxic effect of Pha-L on DA i cell type I neurons. Our behavioral data revealed that the Pha-L-labeled grafts did not cause a recovery from lesion-induced motor asymmetries. On the contrary, after 7 weeks survival a marked increase of amphetamine-induced rotations was found in group T-Pha-L, while the control rats (group T-saline and T) showed a (restricted) decrease of rotational behavior. In apomorphine-induced rotations there was no difference between experimental and control rats. In conclusion, Pha-L cannot be used successfully as a fetal dopaminergic cell marker for graft-host interactions in long-term survival experiments.