槲皮素对大剂量X线暴露所致PC12细胞氧化性损伤的保护作用

Protective effect of quercetin against oxidative damage induced by high-dose X-ray exposure in PC12 cells

目的探讨槲皮素对PC12细胞的毒性及其对大剂量X线诱导PC12细胞氧化性损伤的保护作用。方法槲皮素6.25,12.5,25,50和100μmol·L-1分别作用于PC12细胞,于24,48和72 h后采用MTT法检测PC12细胞增殖。槲皮素12.5,25和50μmol·L-1分别与PC12细胞预孵育2 h,随后采用4 GyX线辐照PC12细胞,于24 h后,采用MTT法检测PC12细胞增殖反应,黄嘌呤氧化酶法检测细胞内超氧化物歧化酶(SOD)活性,硫代巴比妥法检测丙二醛(MDA)含量,菲啉络合法检测总抗氧化能力(T-AOC),DCFH-DA探针法检测活性氧(ROS)含量。结果槲皮素6.25～100μmol·L-1与PC12细胞作用24 h(r=0.887,P<0.01)和48 h(r=0.872,P<0.01)具有促细胞增殖作用,作用72 h表现出明显的细胞毒性,且随浓度增加毒性增大(r=0.942,P<0.01)。与正常对照组比较,PC12细胞受辐射后细胞增殖反应、SOD活性和T-AOC降低(P<0.01),MDA和ROS含量增加(P<0.01)。与辐照对照组比较,槲皮素12.5,25和50μmol·L-1防护组PC12细胞增殖反应(r=0.751,P<0.01),SOD活性(r=0.837,P<0.01)和T-AOC(r=0.940,P<0.01)随槲皮素浓度增大而增高,MDA含量(r=0.845,P<0.01)和ROS含量(r=0.930,P<0.01)随槲皮素浓度的增高而降低。结论槲皮素对大剂量X线诱导PC12细胞氧化性损伤具有一定的防护作用,在12.5～50μmol·L-1浓度范围内其防辐射作用与浓度呈较好的相关性。

OBJECTIVE To explore the cytotoxicity of quercetin as well as its radioprotective efficacy against high-dose X-ray exposure induced oxidative damage in PC12 cells. METHODS PC12 cells were incubated with quercetin 6.25, 12.5, 25, 50 and 100 μmol·L-1 for 24, 48 and 72 h, respectively, and cell proliferation was measured with MTT assay. PC12 cells were exposed to quercetin 12.5, 25 and 50 μmol·L-1 for 2 h before being irradiated to 4 Gy X-ray. Twenty-four hours later, cell proliferation was measured with MTT assay, and the levels of superoxide dismutase （SOD）, malonedialdehyde （MDA）, toal anti-oxidation capacity （T-AOC） and reactive oxygen species （ROS） were detected by xanthine oxidase, thiobarbituric acid, phenanthroline-complexation and DCFH-DA fluorescent probe methods. RESULTS Quercetin 6.25 -100 μmol·L-1 could improve PC12 cell proliferation for 24 h （r= 0.887, P 〈0.01 ） and 48 h （ r=0.872, P 〈0.01 ） in a concentration-dependent manner. While for 72 h, quercetin 12.5 - 100 μmol·L-1 inhibited PC12 cell proliferation in a concentration-dependent manner （ r = 0.942, P 〈0.01 ）. Compared with normal control group, PC12 cell proliferation, SOD and T-AOC were decreased（P〈0. 01 ） while the levels of ROS and MDA were increased （P〈0.01） after PC12 cell irradiation. Compared with X-ray group, quercetin 12.5, 25 and 50 μmol·L-1 could improve PC12 cell proliferation （ r =0. 751, P 〈 0.01 ）, increase the levels of SOD （ r = 0. 837, P 〈 0.01 ） and T-AOC （ r = 0. 940, P 〈0.01 ）, and decrease the levels of MDA （ r = 0. 845, P 〈 0.01 ） and ROS （ r = 0. 930, P 〈 0.01 ） in a concentration-dependent manner. CONCLUSION Quercetin can ameliorate high-close X-ray exposure induced oxidative damage in PCl2 cells. Within a certain range of concentration, this radiopro- tective efficacy has good concentration-dependent correlation.