Abstract: Objective To test whether protein transduction domain4-Cu, Zn superoxide dismutase fusion protein (PTD4-Cu,Zn-SOD) can penetrate into human astrocytes and whether it can mitigate hypoxic damages in human astrocytes. Methods ① Western blot was employed to analyze penetration of superoxide dismutase(SOD) and PTD4-Cu,Zn-SOD into human astrocytes. ② The human astrocyte cultures were subjected to hypoxia, then were respectively treated with dulbecco's modified eagle's medium(DMEM) (Control), SOD (2 μmol/L) and PTD4-Cu,Zn-SOD(PTD4-SOD, 2 μmol/L). Flow cytometry was performed to analyze apoptosis in human astrocytes labeled with Annexin V/PI apoptosis Kits. Results ① PTD4-SOD, but not SOD, penetrated into human astrocyte cultures after 60 min incubation. ② Although 0.5-2.0 μmol/L SOD did not penetrate into human astrocytes, 2.0 μmol/L (not 0.5 mol/L and 1.0 μmol/L) PTD4-SOD did. ③ Hypoxia-induced apoptosis in (27.03±0.50)% of astrocytes. SOD and PTD4-SOD significantly reduced apoptotic cells to (23.29±0.58)% and (12.06±0.19)% of total cells, respectively. Conclusions PTD4-Cu,Zn-SOD can penetrate the membrane of human astrocytes and reduce hypoxia-induced apoptosis,depending on the incubation time and dosage.
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