Intrastriatal grafts of fetal ventral mesencephalon improve allodynia-like withdrawal response to mechanical stimulation in a rat model of Parkinson's disease

We previously reported that a unilateral 6-hydroxydopamine (6-OHDA) rat model of Parkinson's disease showed allodynia-like withdrawal response to mechanical stimulation of the ipsilateral side of the rat hindpaw. The goal of this study was to investigate the effect of intrastriatal grafts of fetal ventral mesencephalon (VM) on the withdrawal response in 6-OHDA rats. The withdrawal threshold in response to the mechanical stimulation of the rat hindpaw was measured using von Frey filaments. In the ipsilateral side of the 6-OHDA lesions, the withdrawal threshold in response to mechanical stimulation significantly increased in 6-OHDA rats with VM grafts compared with those with sham grafts, but did not change in the contralateral side at 5 weeks after transplantation. The present results suggest that the intrastriatal grafts of fetal VM may relieve pain sensation induced by mechanical stimulation in 6-OHDA rats.