Effects of exposure to 1.8 GHz radiofrequency field on the expression of Hsps and phosphorylation of MAPKs in human lens epithelial cells
Effects of exposure to 1.8 GHz radiofrequency field on the expression of Hsps and phosphorylation of MAPKs in human lens epithelial cells
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DOI：
10.1038/cr.2008.306
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发表时间：
2008-12
期刊：
影响因子：
44.1
通讯作者：
Yibo Yu;K. Yao;Wei Wu;Kai-jun Wang;Guangdi Chen;D. Lu
中科院分区：
文献类型：
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作者：
Yibo Yu;K. Yao;Wei Wu;Kai-jun Wang;Guangdi Chen;D. Lu
在许多国家，由于移动电信设备的使用增加，公众日益关注接触移动电话的射频场可能对健康造成的影响。这反过来又导致同源流行病学和实验调查的增加。然而，这些研究的结果是矛盾的。一些研究表明，吸烟会增加健康风险，但大多数研究表明，吸烟对健康没有影响。晶状体上皮细胞（lec）是晶状体前表面的单层立方细胞，具有增殖能力，对维持晶状体的代谢稳态和透明度具有重要意义。LECs损伤已被发现与白内障的发生有关。为了研究暴露于1.8 GHz射频是否会影响LECs的细胞生理，研究人员评估了暴露于全球移动通信系统（GSM） 1.8 GHz射频后人类LECs中热休克蛋白（Hsps）的表达和丝裂原活化蛋白激酶（MAPKs）的激活。2 W/kg的平均比吸收率（SAR）水平是国际非电离辐射防护委员会（ICNIRP）规定的手机微波辐射的安全限值。此外，根据1998年ICNIRP的指导方针，现有的实验证据表明，即使在最敏感的组织中，不可逆效应的阈值也大于4 W/kg，这被推荐为职业性全身暴露限制，传统的安全系数为10，即0.4 W/kg。另一方面，我们希望获得明显的微波辐射生物效应，以探讨微波诱发白内障的潜在机制。因此，我们在研究中选择了1、2、3和4 W/kg的sar。在整个暴露过程中，温度从未在37±0.108ºC范围内波动；所有数据和实验设置每10 s由计算机存储一次。假手术与暴露手术的温差从未超过0.108ºC。热休克蛋白是一个参与蛋白质折叠、修复和降解的应激激活蛋白家族，它表征了细胞对各种应激的反应，如pH值变化、重金属和温度突然升高等。热休克蛋白按分子量分为Hsp90、Hsp70、Hsp60四大家族，小热休克蛋白如Hsp10、Hsp27、αA-crystallin、αB-crystallin。这些蛋白质的主要功能是协助蛋白质折叠。热休克蛋白还有助于防止应激刺激后的细胞凋亡，为修复机制发挥作用留出时间。在暴露于射频场（SAR: 1,2,3,4 W/kg） 2小时后，我们立即通过western blot分析评估了热休克蛋白的表达。尽管与假暴露细胞相比，暴露于射频场的细胞（SAR: 2,3,4 W/kg）中Hsp27和Hsp70的表达发生了显著变化，但未观察到Hsp90的表达差异（图1A和1B）。据报道，将人重建表皮（hRE）暴露于900 MHz射频（2w /kg）下48小时可诱导Hsp70表达[4]轻微但显著增加。Kwee等人曾报道，将转化的人上皮羊膜细胞暴露在960 MHz的GSM信号下，可以诱导Hsp70的表达，而不是Hsp27
The growing public concerns about the possible health effects of exposure to radio frequency (RF) fields from mobile telephones have arisen in many countries because of the increased use of mobile telecommunication devices. This in turn has led to an increase in cognate epidemiological and experimental investigations. However, the results of these studies are conflicting. Some have implicated an increased health risk [1], but most studies have shown no effects [2]. The lens epithelial cells (LECs) are a single layer of cuboidal cells at the anterior surface of the lens, which retain the proliferative capacity and are important for maintaining the metabolic homeostasis and transparency of the lens. Damage to LECs has been found to be associated with cataractogenesis. To investigate whether exposure to 1.8 GHz RF can influence the cellular physiology of the LECs, the expression of heat shock proteins (Hsps) and the activation of mitogen-activated protein kinases (MAPKs) in human LECs after exposure to the 1.8 GHz RF of a global system for mobile communications (GSM) were evaluated. The average specific absorption rate (SAR) level of 2 W/kg is the safety limit for mobile phone microwave radiation emission as defined by the ICNIRP (International Commission on Non-Ionizing Radiation Protection). Furthermore, as per the guidelines of the ICNIRP in 1998, the available experimental evidence indicated that the threshold for irreversible effects in even the most sensitive tissues was greater than 4 W/kg, which is recommended as the occupational whole-body exposure restriction with a traditional safety factor of ten, which translates to 0.4 W/kg. On the other hand, we intended to obtain obvious bio-effects of microwave radiation so as to investigate the potential mechanism of microwave-induced cataract. Therefore, we chose the SARs of 1, 2, 3, and 4 W/kg in our study. During the entire course of exposure, the temperature never fluctuated over the range of 37±0.108 ºC; all data and experimental settings were stored by the computer every 10 s. The temperature difference between sham and exposure never exceeded 0.108 ºC. Hsps are a family of stress-activated proteins that participate in protein folding, repair, and degradation, which characterize the cellular responses to various types of stresses, such as changes in pH, heavy metal, and sudden temperature increases [3]. Hsps are classified into four major families according to their molecular weights: Hsp90, Hsp70, and Hsp60, and the small Hsps, such as Hsp10, Hsp27, αA-crystallin, and αB-crystallin. A main function of these proteins is to assist in protein folding. Hsps also help to prevent apoptosis after a stress stimulus, allowing time for the repair mechanisms to act. We evaluated Hsp expression by western blot analysis immediately after exposure to RF fields (SAR: 1, 2, 3, 4 W/kg) for 2 h. Although a significant change in Hsp27 and Hsp70 was observed in RF-exposed cells (SAR: 2, 3, 4 W/kg) compared with sham-exposed cells, no significant difference was observed for Hsp90 (Figure 1A and 1B). It has been reported that exposure of human reconstructed epidermis (hRE) to 900 MHz RF at 2 W/kg for 48 h induced a slight but significant increase in Hsp70 expression [4]. Kwee et al.[5] have reported that the expression of Hsp70, but not Hsp27, was induced when transformed human epithelial amnion cells were exposed to a GSM signal of 960 MHz at