低氧对新生猪G_1/S期肾小管上皮细胞增殖周期的影响

Effect of hypoxia on cell cycle of G1/S renal tubular epithelial cells of the newborn pig

摘要:

目的：围生期肾小管上皮细胞 (RTEs)急性损伤是否与窒息所致肾组织早期低氧环境直接相关,始终是国内外学术界争论的焦点。该实验以处于细胞增殖周期关键性调控点G1/S界面的RTEs作为体外低氧损伤的靶细胞,进行低氧对G1/S细胞增殖周期影响的研究 ,拟探讨低氧与RTEs急性损伤的关系。方法：以新生猪G1/S期RTEs作为研究对象,采用氰化钠体外低氧损伤制成细胞缺氧模型 (缺氧组 ) ,同时设干预组 (斑螯素 +氰化钠 )和未处理对照组。应用流式细胞术DNA检测法 ,比较缺氧组、干预组和对照组细胞在恢复 0 ,6 0 ,12 0 ,180minG1、S期细胞分布率以及凋亡细胞比率 ,同时应用免疫细胞化学比较三组细胞 p2 1的表达。结果：恢复 0 ,6 0min ,缺氧组S期细胞分布率明显低于干预组 (1.4 %± 2 .5 %vs 98.3%± 1.6 % ;0 .5 %± 0 .9%vs 99.0 %± 1.0 % ;P <0 .0 1) ;在恢复 12 0、180min缺氧组凋亡细胞的比率 (33.6 %± 0 .8% ,37.5 %± 1.2 % )明显高于干预组 (2 0 .9%±1.7% ,2 2 .5 %± 1.1% )和对照组 (2 5 .6 %± 1.1,2 3.6 %± 1.4 % ) (均P <0 .0 1) ;G1期细胞分布率与相应细胞内p2 1的表达呈正线性关系 (r =0 .6 4 ,P <0 .0 1) ,而与凋亡细胞比率则无相关关系 (r =0 .342 ,P >0 .0 5 )。结论：围生期RTEs急性损伤与低氧密切相关，其机制可能与低氧抑制G1/S期RTEs增殖周期的转化，增加S期细胞凋亡相关。

Abstract:

OBJECTIVE: It is still unexplained whether hypoxia of renal tissues induced by asphyxia is closely related to acute renal tubular epithelial cells (RTEs) injury. This paper aims to study the effect of hypoxia on G 1/S transition in neonatal pig's RTEs in vitro so as to explore the relationship between hypoxia and acute RTEs injury. METHODS: A hypoxic cell model of G 1/S transition of RTEs in neonatal piglets was established by sodium cyanide exposure. Some of the hypoxic G 1/S cells received cantharidin and were used as the Intervention group. The non-hypoxic and non-interfered G 1/S cells were used as the Control group. Cell distribution rate and cell apoptosis rate of G 1 and S phases were determined by flow cytometry 0, 60, 120 and 180 minutes after cessation of hypoxia. The cell p21 expression was measured by immunocytochemistry. RESULTS: The cell cycle distribution rate of the S phase in the Hypoxic group 0 and 60 minutes after cessation of hypoxia ( 1.4%± 2.5% and 0.5%± 0.9%) were lower than those of the Intervention group ( 98.3%± 1.6% and 99.0%± 1.0%) (P< 0.01). The cell apoptosis rates in the Hypoxic group 120 and 180 minutes after cessation of hypoxia ( 33.6%± 0.8% and 37.5%± 1.2%) were higher than those of the Intervention group ( 20.9%± 1.7% and 22.5%± 1.1%) and the Control group ( 25.6%± 1.1% and 23.6%± 1.4%) (P< 0.01). The cell distribution rate of the G 1 phase had a positive liner correlation with cell p21 expression of the same term (r= 0.64, P< 0.01), but it was not related to the cell apoptosis rate. CONCLUSIONS: Acute RTEs injury in the perinatal period is closely related to hypoxia. The possible mechanism is that hypoxia may restrain the advance of G 1/S transition and increase cell apoptosis rate of the S phase.