Caruso Rita Loch, Upham Brad L, Harris Craig, Trosko James E
Toxicology Program, Department of Environmental Health, University of Michigan, 1420 Washington Heights, Ann Arbor, Michigan 48109-2029, USA.
Toxicol Sci. 2005 Aug;86(2):417-26. doi: 10.1093/toxsci/kfi208. Epub 2005 May 18.
The insecticide lindane (gamma-hexachlorocyclohexane) inhibits gap junction intercellular communication in rat myometrial cells by a mechanism involving oxidative stress. We hypothesized that oxidation of reduced glutathione (GSH) to glutathione disulfide (GSSG) and subsequent S-glutathionylation provide a mechanistic link between lindane-induced oxidative stress and lindane's inhibition of myometrial gap junction communication. Gap junction communication between cultured rat myometrial myocytes was assessed by Lucifer yellow dye transfer after microinjection. A biphasic pattern was confirmed, with dye transfer nearly abolished after 1 h of exposure to 100 microM lindane followed initially by recovery after lindane removal, and then the development 4 h after termination of lindane exposure of a delayed-onset, sustained inhibition that continued for 96 h. As measured by HPLC, cellular GSH varied over a 24-h period in a biphasic fashion that paralleled lindane-induced inhibition of dye transfer, whereas GSSG levels increased in a manner inversely related to GSH. In accordance, GSH/GSSG ratios were depressed at times when GSH and dye transfer were low. Lindane substantially increased S-glutathionylation in a concentration-dependent manner, measured biochemically by GSSG reductase-stimulated release of GSH from precipitated proteins. Furthermore, treatments that promoted accumulation of GSSG (50 microM diamide and 25 microM 1,3-bis(2-chloroethyl)-1-nitrosourea [BCNU]) inhibited Lucifer yellow dye transfer between myometrial cells. Findings that lindane induced GSH oxidation to GSSG with increased S-glutathionylation, together with the diamide and BCNU results, suggest that oxidation of GSH to GSSG is a component of the mechanism by which lindane inhibits myometrial gap junctions.
杀虫剂林丹（γ-六氯环己烷）通过一种涉及氧化应激的机制抑制大鼠子宫肌层细胞间的缝隙连接通讯。我们推测，还原型谷胱甘肽（GSH）氧化为谷胱甘肽二硫化物（GSSG）以及随后的S-谷胱甘肽化作用在林丹诱导的氧化应激与林丹对子宫肌层缝隙连接通讯的抑制之间提供了一种机制联系。通过显微注射后荧光素黄染料转移来评估培养的大鼠子宫肌层肌细胞间的缝隙连接通讯。确认了一种双相模式，暴露于100μM林丹1小时后染料转移几乎被消除，最初在去除林丹后恢复，然后在林丹暴露终止4小时后出现延迟发作的持续抑制，持续96小时。通过高效液相色谱法测定，细胞内GSH在24小时内呈双相变化，与林丹诱导的染料转移抑制平行，而GSSG水平的增加与GSH呈负相关。相应地，当GSH和染料转移较低时，GSH/GSSG比值降低。林丹以浓度依赖的方式显著增加S-谷胱甘肽化作用，通过GSSG还原酶刺激沉淀蛋白释放GSH进行生化测定。此外，促进GSSG积累的处理（50μM二酰胺和25μM 1,3-双（2-氯乙基）-1-亚硝基脲[BCNU]）抑制子宫肌层细胞间的荧光素黄染料转移。林丹诱导GSH氧化为GSSG并增加S-谷胱甘肽化作用的结果，以及二酰胺和BCNU的结果表明，GSH氧化为GSSG是林丹抑制子宫肌层缝隙连接的机制的一个组成部分。
