Eriocaulon buergerianum extract protects PC12 cells and neurons in zebrafish against 6-hydroxydopamine-induced damage

Background: Ericaulon buergerianum (Gujingcao) is an ophthalmic, anti-inflammatory and antimicrobial Chinese
medicinal herb. This study aims to investigate the neuroprotective effects of Ericaulon buergerianum ethanol extract
(EBE) and to elucidate its underlying action mechanism.
Methods: The viability of dopaminergic (DA) neuron in zebrafish was examined by anti-tyrosine hydroxylase (TH)
immunostaining. The locomotor activity of zebrafish was assessed with a digital video tracking system. The viability
and cellular damage of the PC12 cells were determined by MTT and LDH assays respectively. The nuclear
morphological changes in apoptotic cells were evaluated with DNA staining by Hoechst 33342 dye. Intracellular
nitric oxide (NO) was quantified by DAF-FM diacetate staining. The expression of inducible nitric oxide synthase
(iNOS) was determined by Western blot.
Results: EBE inhibited the 6-OHDA-induced decrease in total distance of movement in zebrafish. Pretreatments of
EBE (25, 50, 100 and 200 μg/ml) increased the viability of 6-OHDA-damaged PC12 cells in a dose dependent
manner. Protection against 6-OHDA-induced nuclear fragmentation and accumulation of apoptotic bodies was also
observed in EBE pretreated cells. Anti-oxidative (inhibition of NO production and iNOS expression in PC12 cells in
vitro) activities of EBE are related to its neuroprotective effects in 6-OHDA-induced DA neuron damage.
Conclusion: EBE exhibited significant neuroprotective activities in zebrafish, including recovery of dopaminergic
neuron loss caused by 6-OHDA in a dose-dependent manner in vivo, inhibition of 6-OHDA-induced decrease of
total distance in movement in zebrafish. The iNOS-NO pathway may be involved.