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目的探讨P53/P53上调凋亡调控因子(PUMA)通路在苯并[a]芘(B[a]P)所致脑皮质神经细胞凋亡中的作用。方法无特定病原体级健康雄性SD大鼠45只随机分为空白对照组、溶剂对照组和低、中、高剂量组,每组9只。3个剂量组分别予1.00、2.50和6.25 mg/kg体质量的B[a]P(以橄榄油溶解),溶剂对照组予1.00mL/kg体质量橄榄油,隔日腹腔注射染毒12周,空白对照组不作任何处理。大鼠染毒结束处死后,每组随机取3只采用TUNEL法检测脑皮质组织细胞凋亡率,余下6只大鼠采用硫代巴比妥酸法和水溶性四氮唑-1法分别检测脑皮质组织丙二醛(MDA)水平和超氧化物歧化酶(SOD)活力,采用免疫印迹法检测脑皮质组织P53和PUMA蛋白相对表达水平。结果低、中和高剂量组大鼠脑皮质细胞凋亡率均分别高于空白对照组和溶剂对照组(P<0.01),高剂量组大鼠脑皮质细胞凋亡率均分别高于低和中剂量组(P<0.01)。高剂量组大鼠脑皮质组织MDA水平分别高于其余4组(P<0.01),SOD活力均分别低于其余4组(P<0.01);中剂量组大鼠脑皮质组织SOD活力低于溶剂对照组(P<0.05)。3个剂量组大鼠脑皮质组织P53和PUMA蛋白的相对表达水平均分别高于空白对照组和溶剂对照组(P<0.01);大鼠脑皮质组织P53和PUMA蛋白相对表达水平均随B[a]P染毒剂量的增加而增加(P<0.05),呈剂量-效应关系。结论 B[a]P亚慢性染毒可导致大鼠脑皮质组织细胞凋亡,可能机制是B[a]P引起大鼠脑神经细胞氧化应激,通过P53/PUMA通路介导脑皮质细胞凋亡。
Objective To investigate the role of P53 / P53 upregulating PUMA pathway in the apoptosis of cerebral cortical neurons induced by benzo [a] pyrene (B [a] P). Methods 45 healthy male SD rats without specific pathogen were randomly divided into blank control group, solvent control group and low, medium and high dose groups, with 9 rats in each group. The three dose groups were given 1.00, 2.50 and 6.25 mg / kg B [a] P (dissolved in olive oil) respectively, and the solvent control group was given 1.00 mL / kg body weight olive oil. Each of the three dose groups was injected intraperitoneally for 12 weeks, Blank control group without any treatment. After the rats were sacrificed at the end of the exposure, three rats in each group were randomly divided into three groups to detect the apoptosis rate of cerebral cortex tissue by TUNEL method. The remaining six rats were detected by thiobarbituric acid method and water-soluble tetrazolium-1 method The levels of malondialdehyde (MDA) and superoxide dismutase (SOD) in cerebral cortex were measured. The relative expression levels of P53 and PUMA protein in cerebral cortex were detected by Western blotting. Results The apoptotic rates of cerebral cortical cells in the low, middle and high dose groups were higher than those in the blank control group and the solvent control group (P <0.01). The apoptotic rates of the cerebral cortex in the high dose group were higher than those in the low and middle Medium dose group (P <0.01). Compared with the other four groups, the MDA level in the high-dose group was significantly higher than that in the other four groups (P <0.01), while the SOD activity in the middle-dose group was lower than that in the other four groups (P <0.01) Control group (P <0.05). The relative expression levels of P53 and PUMA protein in cerebral cortex tissue of 3 dose groups were higher than that of blank control group and solvent control group respectively (P <0.01) a] P dose increased (P <0.05), showing a dose-response relationship. Conclusions Chronic exposure to B [a] P can induce apoptosis of rat cerebral cortex tissue. The possible mechanism is that B [a] P induces oxidative stress in rat brain cells and mediates the apoptosis of cerebral cortex cells through P53 / PUMA pathway Death.