Study On The Protective Effects And Mechanisms Of Tetrahydroxystibene Glucoside On Lps-induced Dopaminergic Neuronal Damage

Objective: To investigate the protective effects of tetrahydroxystibene glucoside(TSG) on lipopolysaccharide(LPS)-induced dopaminergic(DA) neuronal damage in rats. Methods: Primary rat neuron-glia co-cultures were prepared from the ventral midbrain tissues of embryonic day 14-15. The cultures were randomly divided into control, TSG(80 μmol/L), LPS(10 ng/m L) and LPS+TSG( 20-80 μmol/L) groups. LPS-induced DA neuronal damage was evaluated by immunochemical staining with anti-tyrosine hydroxylase(TH) antibody. The levels of nitric oxide(NO), TNF-α and IL-1β in the culture medium were measured with Griess reagent and enzyme link immunosorbent assay(ELISA), respectively. Primary microglia were isolated from neonatal rats and cultured in vitro. The protein expressions of ionized calcium-binding adapter molecule-1(Iba-1) and NF-κB signaling pathway(p65) were detected by western blotting assay. In addition, an in vivo model was induced by direct injection of LPS(5 ug) into rat substantia nigra(SN). After seven daily intraperitoneal injection of TSG, the brains were removed, sectioned and processed for quantification of DA neurons by immunochemial staining using anti-TH and OX-42(the specific marker of microglia) antibodies. Results: In rat midbrain neuron-glia co-cultures, TSG protected LPS-induced DA neuronal damage and inhibited LPS-induced increase of NO, TNF-α and IL-1β in the culture medium. In the primary microglia culture, TSG suppressed LPS-induced acitivation of Iba-1 and NF-κB(p65) signaling pathway. In in vivo experiments, LPS induced decrease of DA neurons and activation of microglia in rat SN, which could be attenuated by TSG treatment. Conclusion: TSG protects DA neuronal damage against LPS-induced neurotoxicity both in vivo and in vitro and these effects are in part related to inhibiting microglia activation and the subsequent pro-inflammatory factors release.