Abstract: OBJECTIVE: To investigate the effect of Roucongrong(Herba Cistanches Deserticolae) decoction on the substantia nigra in rats with Parkinson's disease(PD) induced by 6-hydroxydopamine hydrochloride(6-OHDA). To further determine whether the Wnt/β-catenin signaling pathway is involved in the action.METHODS: A rat model of PD was established by intracranial injection of 6-OHDA. Subsequently,three concentrations of Roucongrong(Herba Cistanches Deserticolae) decoction were prepared and administered to rats by gavage therapy for 14 d. Behavioral changes were measured in PD rats. In vivo tyrosine hydroxylase(TH) levels in the substantia nigra were examined by immunohistochemistry.Additionally, gene and protein expression levels of members of the Wnt/β-catenin signaling pathway were examined by Western blotting and polymerase chain reaction. Lastly, a Wnt/β-catenin inhibitor was used to investigate the mechanism of action in 1-methyl-4-phenylpyridinium(MPP +)-treated MES23.5 cells in vitro.RESULTS: Roucongrong(Herba Cistanches Deserticolae) decoction improved performance in the stride and gait adjustment tests in PD rats. It also increased TH in the substantia nigra and altered the expression of genes and proteins in the Wnt/β-catenin signaling pathway. Wnt/β-catenin inhibitor reduced the effect of Roucongrong(Herba Cistanches Deserticolae) decoction in MPP +-treated MES23.5 cells.CONCLUSION: Roucongrong(Herba Cistanches Deserticolae) decoction may promote neuronal survival in PD in vivo and in vitro by increasing TH content in the substantia nigra and by activating the Wnt/β-catenin signaling pathway.

Key words: Cistanche, Parkinson disease, survival, tyrosine 3-monooxygenase, Wnt signaling pathway