Behavioural recovery on simple and complex tasks by means of cell replacement therapy in unilateral 6-hydroxydopamine-lesioned mice.

Before cell replacement therapies can enter the clinic, it is imperative to test the therapeutic benefits in well-described animal models. In the present study, we aimed to investigate the effects of 6-hydroxydopamine lesions to the medial forebrain bundle and subsequent grafting of embryonic day (E)12.5 ventral mesencephalon into the denervated striatum in C57/Bl6 mice on a battery of simple motor tests (drug-induced rotation, rotarod, and corridor) and the lateralised choice reaction time task conducted in the mouse nine-hole box. Histological analysis confirmed effective lesions and good graft survival. The lesion induced marked deficits in the choice reaction time task, the rotarod test, and corridor test, and these deficits were partially but significantly alleviated in the grafted mice. Although the lesions induced significant rotation following injections of amphetamine and apomorphine, respectively, the grafts did not, suprisingly, alleviate the rotation deficit. This study shows the ability of ventral mesencephalic tissue to ameliorate some of the lesion-induced deficits, and the power of operant testing in detecting small but significant improvements. The behavioural tests presented are useful drug-free approaches for evaluating cell-based therapies.