PC12细胞应激损伤中能量限制的效应及SIRT3的表达

目的 研究H2O2诱导的PC12细胞氧化应激损伤中,能量限制(CR)及SIRT3参与的调控效应.方法 实验分4组:H2O2组,H2O2+CR组,CR组和正常对照组;MTT法检测不同浓度H2O2作用下CR对细胞生存率的影响;TUNEL染色法检测过氧化氢作用后CR对细胞的凋亡的影响;免疫荧光检测PC12细胞中SIRT3的表达定位;RT-PCR及Western印迹检测SIRT3、Caspase-3的表达变化.结果 60μmol/L H2O2作用6 h后,H2O2组细胞生存率(74.01±2.21)%可维持在70%以上,与对照组比较差异有统计学意义(P＜0.05);120μmol/L H2O2作用下,H2O2组的细胞活力显著下降(38.22±3.34)%,后续研究选取60μmol/L H2O2浓度作为应激源;60μmol/L H2O2作用6 h后H2O2组细胞生存率(74.01±2.21)%与CR+H2O2组(97.26±1.92)%间比较差异有统计学意义(P＜0.05).TUNEL凋亡检测H2O2+CR组凋亡率较H2O2组显著降低.免疫荧光双染色证实PC12细胞中SIRT3为一种线粒体蛋白.Western印迹显示与正常对照组(5256±144)比较,CR组中SIRT3表达升高(6857±157),差异有统计学意义(P＜0.05)、H2O2组中表达降低(3786±160),差异有统计学意义(P＜0.05).与H2O2组(3786±160)比较,CR+H2O2组中SIRT3表达上升(5056±121),差异有统计学意义(P＜0.05).与正常对照组比较(5342±420),H2O2组中Caspase-3表达升高(8499±426),差异有统计学意义(P＜0.001).CR+H2O2组(5750±438)中Caspase-3表达较H2O2组表达下降(8499±426),差异有统计学意义(P＜0.001).RT-PCR显示与正常对照组(6204±134)比较,CR组(7214±148)中SIRT3表达升高,差异有统计学意义(P＜0.05)、H2O2组中表达降低(4807±143),差异有统计学意义(P＜0.05).与H2O2组(4807±143)比较,CR+H2O2组中SIRT3表达上升(6195±166),差异有统计学意义(P＜0.05).结论 PC12细胞中,CR具有抗氧化应激损伤及凋亡的效应;CR可上调PC12细胞中SIRT3的表达,在H2O2诱导的PC12应激损伤中CR-SIRT3的调控具有保护效应,SIRT3是否具有延缓神经元衰老作用值得进一步研究.

Abstract：

Objective To study the regulation effects of CR (caloric restriction) and SIRT3 in the H2O2-induced oxidative stress injury of PC12 cell. Methods The cells were divided into four groups:H2O2, H2O2+CR, CR and control (high glucose). For control and H2O2 group, cells were cultured in DMEM containing 0.45% glucose; for group in CR condition, cells were treated with the medium containing 0.1% glucose. For groups with H2O2, the H2O2 was diluted in EMEM medium to obtain the final concentration containing 60 μmol/L. Viability of PC12 cells were measured by MTT assay. The medium was refreshed with different concentration of H2O2 (from 10 to 120 μmol/L). The absorbance of the samples was measured at 492 nm using a microtiter plate reader. We detected TUNEL-positive cells using the In Situ Cell Apoptosis Detection kit pretreated with CR and H2O2. Immunofluorescence double staining detected the expression and localization of SIRT3. RT-PCR and Western-blot mehtods detected the expression of SIRT3,Caspase-3. Results After pretreating with 60 μmol/L H2O2 for 6 h, the viability of PC12 cells in H2O2 group (74.01±2.21)% retained above 70%, and have statistical significance contrasted with control group (P＜0.05); After pretreating with 120μmol/L H2O2, the viability of PC12 cells declined significantly (38.22±3.34)%. So 60μmol/L H2O2 is our experiment concentration . The viability of H2O2 group (74.01±2.21)% was much lower than CR + H2O2 group (97.26±1.92)% (P＜0.05). After pretreating with H2O2, TUNEL staining showed the apoptosis cells of CR+H2O2 group decreased significantly contrasted with H2O2 group. The immunofluorescence double staining results showed that SIRT3was a mitochondria protein. Western-blot showed the expression of SIRT3 in CR group (6857±157) (P＜0.05) increased and decreased in H2O2 group (3786±160) (P＜0.05) contrasted with control group (5256±143). The expression of SIRT3 in CR + H2O2 group(5056±121)(P＜0.05)increased contrasted with H2O2 group(3786±160). We also detected that Caspase-3 in H2O2 group(8499±426)(P＜0.001 )was much higher than control group than (5342±420), but in the CR + H2O2 group (5750±438 ) theexpression of Caspase-3 was much lower than H2O2 group(8499±426) (P＜0.001). RT-PCR also showed that the expression of SIRT3 in CR group (7214±148) increased and decreased in H2O2 group (4807±143 ) (P＜0.05) contrasted with control group (6204 ± 134 ). The expression of SIRT3 in CR + H2O2 group (6195 ± 166) increased contrasted with H2O2 group (4807 ± 143 ) ( P＜0.05). Conclusion CR causes anti-oxidative injury and has apoptotic effects in PC12 cell. It up-regulates the expression of SIRT3 and the effects of CR-SIRT3 can prevent PC12 cell from H2O2-induced apoptosis. And SIRT3 may be a novel molecule of regulating target in the delay of neuronal senescence.

Effects of caloric restriction on the oxidative stress injury and the expression of SIRT3 in PC12 cell

Objective To study the regulation effects of CR (caloric restriction) and SIRT3 in the H2O2-induced oxidative stress injury of PC12 cell. Methods The cells were divided into four groups:H2O2, H2O2+CR, CR and control (high glucose). For control and H2O2 group, cells were cultured in DMEM containing 0.45% glucose; for group in CR condition, cells were treated with the medium containing 0.1% glucose. For groups with H2O2, the H2O2 was diluted in EMEM medium to obtain the final concentration containing 60 μmol/L. Viability of PC12 cells were measured by MTT assay. The medium was refreshed with different concentration of H2O2 (from 10 to 120 μmol/L). The absorbance of the samples was measured at 492 nm using a microtiter plate reader. We detected TUNEL-positive cells using the In Situ Cell Apoptosis Detection kit pretreated with CR and H2O2. Immunofluorescence double staining detected the expression and localization of SIRT3. RT-PCR and Western-blot mehtods detected the expression of SIRT3,Caspase-3. Results After pretreating with 60 μmol/L H2O2 for 6 h, the viability of PC12 cells in H2O2 group (74.01±2.21)% retained above 70%, and have statistical significance contrasted with control group (P＜0.05); After pretreating with 120μmol/L H2O2, the viability of PC12 cells declined significantly (38.22±3.34)%. So 60μmol/L H2O2 is our experiment concentration . The viability of H2O2 group (74.01±2.21)% was much lower than CR + H2O2 group (97.26±1.92)% (P＜0.05). After pretreating with H2O2, TUNEL staining showed the apoptosis cells of CR+H2O2 group decreased significantly contrasted with H2O2 group. The immunofluorescence double staining results showed that SIRT3was a mitochondria protein. Western-blot showed the expression of SIRT3 in CR group (6857±157) (P＜0.05) increased and decreased in H2O2 group (3786±160) (P＜0.05) contrasted with control group (5256±143). The expression of SIRT3 in CR + H2O2 group(5056±121)(P＜0.05)increased contrasted with H2O2 group(3786±160). We also detected that Caspase-3 in H2O2 group(8499±426)(P＜0.001 )was much higher than control group than (5342±420), but in the CR + H2O2 group (5750±438 ) theexpression of Caspase-3 was much lower than H2O2 group(8499±426) (P＜0.001). RT-PCR also showed that the expression of SIRT3 in CR group (7214±148) increased and decreased in H2O2 group (4807±143 ) (P＜0.05) contrasted with control group (6204 ± 134 ). The expression of SIRT3 in CR + H2O2 group (6195 ± 166) increased contrasted with H2O2 group (4807 ± 143 ) ( P＜0.05). Conclusion CR causes anti-oxidative injury and has apoptotic effects in PC12 cell. It up-regulates the expression of SIRT3 and the effects of CR-SIRT3 can prevent PC12 cell from H2O2-induced apoptosis. And SIRT3 may be a novel molecule of regulating target in the delay of neuronal senescence.