Regulation Effects Of Catalpol On Astrocytes Induced By Rotenone

Rotenone, a kind of pesticides that suppresses mitochondrial function has toxic effects on the central nervous system, and it may be involed in the initiation and progression of Parkinson’s disease. The glial cells such as astrocytes and microglia, supporting and regulating the nervous system, interact with neurons and they together constitute the nervous system. Catalpol is an iridoid glycoside contained richly in the roots of Rehmannia glutinosa Libosch. This study aimed to investigate the neuroprotective effects and the mechanism of catalpol in astrocytes induced by rotenone, the cell model of PD. The main results are summaried as follows.(1) We isolated and cultured astrocytes and microglias from mice cerebral cortex, the purity are all above 90% by immune dyeing identification. The morphology of astrocytes and microglias induced by different concentrations of rotenone changed and their cell viabilities decreased in different degrees and astrocytes has high resistance to rotenone.(2) The PD cell model was established by rotenone induced astrocytes for 24 h, and astrocytes were pretreated with catalpol for 0.5 h and then were used to detecte the protective effect of catalpol. MTT assay, morphological method and other biochemistry detection methods demonstrated that catalpol could significantly increase the astrocytes viability and improve the morphology of astrocytes induced by rotenone. In addition, catalpol could significantly reduce the intracellular ROS formation via the enhancement of GSH in astrocytes. Furthermore, catalpol attenuated the activity of caspase-3 and the extracellular glutamate concentration in astrocytes treated with rotenone. Collectively, these results suggested that catalpol exerted the neuroprotective effects was involed in its anti-oxidation stress, anti-apoptosis and anti-glutamate excitotoxicity mechanisms in astrocytes induced by rotenone.(3) In order to research the mechanism of catalpol anti-glutamate excitotoxicity, western blotting and real time polymerase chain reaction were used and indicated that treatment of cortical astrocytes with catalpol led to a significant increase of GLAST mRNA and protein expression, which were markedly inhibited by treatment with rotenone, but not obviously alter the expression of GLT-1 mRNA and protein expression. Moreover, by the detection of Na+/K+-ATPase activity, we found that Catalpol-induced recovery of glutamate uptake could be associated with elevating of Na+/K+-ATPase activity, since catalpol could reverse the activity of Na+/K+-ATPase activity. Together, the neuroprotective effect of catalpol might be related to the significant increase of glutamate uptake to inhibit extracellular glutamate in astrocytes against rotenone through increasing expression of GLAST mRNA and protein and reversing the activity of glutamate transporters.All in all, these results suggest that catalpol can protect astrocytes induced by rotenone, the PD model cells. The specific mechanisms may be related to anti-oxidation stress, anti-apotosis, and anti-glutamate excitotoxicity. The anti-glutamate excitotoxic mechanism may be involved in the expression of GLAST mRNA and protein and the activity of Na+/K+-ATPase.