Scutellarin and caffeic acid ester fraction, active components of Dengzhanxixin injection, upregulate neurotrophins synthesis and release in hypoxia/reoxygenation rat astrocytes

Ethnopharmacological relevance: Scutellarin (Scu) and caffeic acid ester fraction (Cat), the extracts from the traditional Chinese herb, Erigeron breviscapus, are known to ameliorate post ischemic neuronal dysfunction. Aim of the study: Neurotrophic factors (NTFs) are essential for neuronal growth and survival. We explored the neuroprotective effect of Scu and Caf by synthesis and release of NGF, BDNF and GDNF in rat astrocytes exposed to hypoxia/reoxygenation and MACO rats. And the neuroprotection of Scu and Caf was also explored. Materials and methods: The primary rat astrocytes were cultured in vitro. The temporal mRNA and protein expression profile during hypoxia/reoxygenation were analyzed using real-time RT-PCR and ELISA. The expression of p-CREB, p-Alct, p-MAPKs and Bax were analyzed by western blotting. Cell viability of neuro-2A was measured using CCK-8 and cell cytotoxicity was measured with LDH release. Results: During hypoxia/reoxygenation a similar decrease pattern of NTFs (NGF, BDNF and GDNF) was observed in both mRNA and protein; Scu and CM enhanced the expressions of NGF, BDNF and GDNF mRNA and protein in astrocytes under hypoxia/reoxygenafion condition. CREB and Akt, but not MAPKs ( p-JNK, p-ERK1/2 and p-38) may be involved in the expression of NTFs. Concomitantly, conditioned medium from astrocytes which was treated by Scu or Caf after hypo3 h/Reox24 h significantly reduced neurotoxicity compared with conditioned medium from hypo3 h/Reox24 h astrocytes alone, and they show the tendency of increased neurons viability accompanied with Bax changes. Conclusions: These results indicate that the neuroprotective effect of Scu and Caf might be mediated, at least in part, via a stimulation of the production and release of NTFs through p-CREB and p-Akt signaling. Furthermore, Scu and Caf could antagonistic the hypoxia induced toxicity through astrocytes conditioned medium. Those results suggested that Scu and Caf might have therapeutic potential for stroke. (C) 2013 Elsevier Ireland Ltd. All rights reserved.