Protective effect of curcumin on H2O2-induced damage of precurosor oligodendrocytes

Abstract

Objective To study the protective effect of curcumin on precurosor oligodendrocytes (preOLs) damage induced by hydrogen peroxide (H2O2),and explore its mechanism.Methods (1) In vitro primary culture ofpreOLs was performed; and 0 (normal controls),100,250 and 500 μmol/L H2O2 were added for 30 min; the apoptosis and death of preOLs were observed by Hoechst33342/PI double staining.(2) The preOLs were divided into normal control group,model group,and 5,10 and 20 μmol/L curcumin treatment groups; cells the later three groups were given 5,10 and 20 μmol/L curcumin for one h,and the later four groups were given 100 μmol/L H2O2 for 30 min; MTT assay was,then,employed to detect the cell viability.(3) The preOLs were divided into normal control group,model group,and 10 μmol/L curcumin treatment group; the apoptosis ofpreOLs was detected by Annexin V/FITC flow cytometry; Western blotting was used to detect the protein expressions of B cell lymphoma/leukemia-2 (Bcl2),Bcl-2 associated X protein (Bax) and cleaved caspase-3 and caspase-9; activities of total superoxide dismutase (T-SOD),glutathione peroxidase (GPx) and catalase (CAT) and malondialdehyde (MDA) were detected by spectrophotometry.Results (1) As compared with those in the normal control group,significantly decreased number of normal healthy cells and statistically increased apoptotic and necrotic cells in the 100,250 and 500 μmol/L H2O2 treatment groups were noted (P＜0.05); 100 μmol/L H2O2 treatment group had larger number of apoptotic cells than that of necrotic cells,while 250 and 500 μmol/L H2O2 treatment groups had larger number of necrotic cells than that of apoptotic cells.(2) Cells from 5,10 and 20 μmol/L curcumin treatment groups had significantly higher preOLs viability than those from model group,and 10 and 20 μmol/L curcumin treatment groups had significantly higher preOLs viability than those from 5 μmol/L curcumin treatment group (P＜0.05).(3) As compared with the model group,the 10 μmol/L curcumin treatment group had obviously decreased apoptotic and necrotic cells,increased activities of T-SOD,GPx and CAT,increased GSH level and decreased MDA concentration,up-regulated Bcl-2 expression,and inhibited Bax,caspase-3 and caspase-9 expressions,with significant differences (P＜0.05).Conclusion Curcumin has protective effect on preOLs against oxidative injury through effectively reducing lipid peroxidation,regulating Bcl-2/Bax expression and suppressing caspase-3 and caspase-9 activation. Key words: Precurosor oligodendrocyte; Oxidative stress; Apoptosis; Curcumin