肾小管上皮细胞S期细胞凋亡过度与G1/S细胞低氧暴露的关系

目的：探讨肾上管上皮细胞（RTEs）S期细胞凋亡过度与G1/S界面细胞低氧直接暴露的关系. 方法：采用NaCN体外细胞化学性低氧法进行G1/S新生猪RTEs低氧干预研究,分别应用反相高效液相法、流式细胞术细胞DNA 含量PI染色分析法和流式细胞术间接细胞免疫化学法进行低氧/再给氧各观察点细胞内ATP含量、细胞周期时相和凋亡细胞分布率以及热休克蛋白（HSP27和HSP70）表达量的检测.并采用磷蛋白磷酸酶（PP2A）抑制剂斑蝥素进行NaCN介导的细胞蛋白质脱磷酸化抑制研究,比较HSP27和HSP70在磷酸化与脱磷酸化状态下细胞凋亡的发生率. 结果：受低氧直接暴露的G1/S新生猪RTEs在S期细胞凋亡比率显著高于PP2A抑制组和空白对照组（P〈0.01）,此时细胞内ATP含量显著低于后两组（P〈0.05）,而细胞内HSP27和HSP70的表达量则均高于后两组（P〈0.01）. 结论：新生猪RTEs发生 S期细胞凋亡过度与其G1/S低氧直接暴露密切相关,其可能机制与NaCN化学性低氧介导的S期HSP27和HSP70的脱磷酸化有关.

Relationship of S period apoptosis excessiveness with G1/ S renal tubular epothelial cells exposed hypoxia

Objective:S period apoptosis excessiveness is one of the main mechanisms that the cell hurt, but it is seldom report induced by hypoxia/re-oxygenation to renal tubular epithelial cells (RTEs). The aim of this study is to investigate the relationship of excessive apoptosis at S period with G_1/ S interface RTEs revealed hypoxia directly. Methodology:The hypoxic intervention's study of new-born pig's RTEs in vitro was adopted NaCN chemistry hypoxia method. The concentration of intracellular ATP, distribution of cell cycle phases, rate of apoptosis and the expression of HSP27 and HSP70 at each time of observation was determined respectively by HPLC method, flow cytometry of DNA content PI dyes and indirect cell immunity chemistry analytical method. The blockade PP2A activity induced by NaCN was studied by interfering the proteins dephosphorylation adopted cantharidin, which is an inhibitor of PP2A, and the rate of the apoptosis conditions in the phosphorylation and unphosphorylation of HSP27/HSP70 was compared. Results:In the new-born pig's RTEs of the G_1/S interface exposed low oxygen directly, the apoptosis ratio at S phase was significantly higher (P<0.01), the expressions of HSP27/ HSP70 amount were markedly increased (P<0.01), while the concentration of intracellular ATP was obviously lower(P<0.05)than that in PP2A blockade and blank matched control groups, at this time. Conclusion:The excessive apoptosis at S period in newborn pig's RTEs is closely related with directly exposing the low oxygen on its G_1/ S interface cells. This mechanism may be associated with the dephosphorylation both of HSP27 and HSP70 induced by chemistry hypoxia.