不同强度永磁磁场对大鼠胰岛细胞超氧化物歧化酶及丙二醛的影响

An experimental study of the impacts of magnetic fields on superoxide dismutase and malondialdehyde in ratpancreatic islet cells

目的研究在正常培养条件下和缺氧培养条件下，不同强度永磁磁场对大鼠胰岛细胞超氧化物歧化酶（SOD）活性及丙二醛（MDA）含量的影响。方法根据大鼠胰岛细胞生长情况，选取培养后第3天的细胞进行实验。在正常培养条件下和缺氧培养条件下分别采用44．8mT、90．6mT和182．1mT3种强度磁场对加磁A组、加磁B组及加磁C组细胞进行干预，对照组细胞不给予任何磁场干预。于磁场干预72h后检测各组细胞培养液中SOD活性及MDA含量。结果通过观察大鼠胰岛细胞生长情况发现，其细胞光密度（OD）值从培养第2天到第5天呈直线增长趋势，故选择培养第3天的细胞进行磁场干预实验。在正常培养条件下，各加磁组SOD活性均低于对照组，其中加磁A组SOD活性与对照组间差异具有统计学意义（P〈0．05）；在缺氧培养条件下，发现各加磁组SOD活性随磁场强度增加呈现先增强、后降低趋势，其中加磁B组、加磁C组SOD活性明显低于对照组水平（P〈0．01）。在正常培养条件下，各加磁组MDA含量均随磁场强度增加而增加，其中加磁C组MDA含量明显高于对照组（P〈0．01）；在缺氧培养条件下，发现各加磁组MDA含量均随磁场强度增加呈现先增加、后降低趋势，其中加磁B组、加磁C组MDA含量均明显低于对照组水平（P〈0．01）。结论在正常培养条件下，磁场干预能降低大鼠胰岛细胞SOD活性，增加MDA含量，呈现氧化损伤效应，并随着磁场强度增加，其氧化损伤程度进行性加重；在缺氧培养条件下，磁场干预在降低大鼠胰岛细胞SOD活性同时，还能降低MDA含量，呈现抗氧化损伤效应，并随着磁场强度增加，其抗氧化损伤效应逐渐增强。

Objective To explore the impacts of magnetic fields of different intensities on the superoxide dismutase （SOD） activity and malondialdehyde （MDA） levels in rat pancreatic islet cells under normal and hypoxic conditions. Methods Rat pancreatic islet ceils were cultured, and after 3 clays were subjected to a magnetic field of either 44.8 mT, 90.6 mT or 182.1 mT under either normal or hypoxic conditions. Control cells received no mag netic field exposure. SOD activity and MDA level were measured after 72 hr. Results The cultured cells grew line arly with optical density （OD） of 0. 067 ±0. 021 after 2 days and 0. 449 ±0.113 after 5 days. SOD activity was sig nificantly lower in the three magnetic field intervention groups than in the control group, Under hypoxie culture condi- tions, in all the magnetic field intervention groups SOD activity increased at first and then decreased. Under normal culture conditions, MDA content was significantly higher in the 182.1 mT group than in the control group. In the oth er two groups it was significantly lower. Conclusion Magnetic field exposure can cause oxidative damage to pan creatic islet ceils, at least rat cells in culture. Under hypoxic culture conditions a magnetic field can inhibit such damage.