RESUMEN
AIM: To explore the role of PI3K/Akt/nNOS in Zhouluotong extract resisting diabetic peripheral neuropathy.METHODS:The Schwann cells were divided into normal group ( D-glucose 25 mmol/L) , model group ( D-glucose 100 mmol/L) , Zhouluotong extract Z-6 +high glucose group, Zhouluotong +high glucose group, mecobalamine+high glucose group.The viability, nitric oxide content and the Ca2+-ATPase activity in Schwann cells were determined by Cell Counting Kit-8 , nitric oxide assay kit and Ca2+-ATPase assay kit, respectively.The apoptosis of Schwann cells were analyzed by flow cytometry.The expression of Bcl-2, Bcl-xL, Bax, Bak and caspase-3, and the phosphorylation levels of nNOS and Akt were determined by Western blotting.The signal pathway of PI3K/Akt was explored by dominant negative PI3K and Akt (δp85 and DN-Akt) transient transfection assay.RESULTS:Under high-glucose culture, the cell viability, nitric oxide content in culture supernatant, the expression of Bcl-2 and Bcl-xL, and the phosphorylation levels of Akt and nNOS in the Schwann cells were significantly increased.The cell apoptosis, the expression of Bax, Bak and caspase 3 in the Schwann cells were significantly decreased by Zhouluotong extract Z-6, compared with model group.In-creased nitric oxide content and the up-regulation of nNOS were observed.However, the effects of blocking PI3K/Akt, the upstream pathway of nNOS , by transfection with DN-δp85 on Akt phosphorylation in the Schwann cells was still unclear. CONCLUSION:Zhouluotong extract Z-6 changes the phosphorylation of nNOS, and the expression of anti-apoptotic fac-tors , caspase-3 and pro-apoptotic factors in Schwann cells under high-glucose culture, thus reducing apoptosis and elevating viability.The relationship to PI3K/Akt/nNOS pathway needs further investigation.