BACKGROUND Boron (B) is an abundant element on earth and presents at physiological pH in the form of boric acid (BA). It has both positive and negative effects on biological systems. BA and sodium borates have been considered as being toxic to the reproduction system in animal experiments. Unfortunately, the molecular mechanism underlying the toxic effects of BA is not fully understood. METHODS Here, we demonstrate the influence of BA on mouse TM3 Leydig cells which are male reproductive system cells targeted by BA exposure. The cytotoxicity was evaluated by MTT and NRU assays. Annexin V-FITC/PI double staining kit, mitochondria membrane potential (ΔΨm) assay kit with JC-1 and caspase-3 colorimetric assay kit were used to indicate the cell death pathway. To estimate the role of oxidative stress in BA induced toxicity, glutathione (GSH) level, catalase (CAT) and superoxide dismutase (SOD) activities were measured manually. RESULTS The cell viability assays showed that BA was not cytotoxic within the tested concentrations up to 1000 μM. Sub-toxic concentrations were used for detecting oxidative stress status. BA exposure was significantly reduced GSH level at 1000 μM and CAT activity in a concentration-dependent manner. However, SOD activity was increased at the tested concentrations (100-1000 μM). Moreover, ΔΨm was significantly decreased at 500 and 1000 μM of BA, while caspase-3 activity was not changed apparently. CONCLUSION These findings demonstrated that BA is not cytotoxic and apoptotic but may slightly induces oxidative stress in TM3 Leydig cells at higher concentrations.

中文翻译：

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硼酸对小鼠TM3 Leydig细胞体外死亡和氧化应激的影响。

背景技术硼（B）是地球上的丰富元素，并且在生理pH下以硼酸（BA）的形式存在。它对生物系统有正面和负面影响。在动物实验中，BA和硼酸钠已被认为对生殖系统有毒。不幸的是，尚未完全了解BA毒性作用的分子机制。方法在这里，我们证明了BA对小鼠暴露于雄性生殖系统细胞TM3 Leydig细胞的影响。通过MTT和NRU分析评估细胞毒性。Annexin V-FITC / PI双重染色试剂盒，带有JC-1的线粒体膜电位（ΔΨm）分析试剂盒和caspase-3比色分析试剂盒用于指示细胞死亡途径。要评估氧化应激在BA诱导的毒性，谷胱甘肽（GSH）水平中的作用，手动测量过氧化氢酶（CAT）和超氧化物歧化酶（SOD）活性。结果细胞活力分析表明，BA在高达1000μM的测试浓度下没有细胞毒性。亚毒性浓度用于检测氧化应激状态。BA暴露以浓度依赖的方式显着降低了1000μM时的GSH水平和CAT活性。但是，SOD活性在测试浓度（100-1000μM）下增加。此外，在500和1000μM的BA下，ΔΨm显着降低，而caspase-3活性没有明显改变。结论这些发现表明，BA在较高浓度下不具有细胞毒性和凋亡作用，但可能会在TM3 Leydig细胞中轻微诱导氧化应激。结果细胞活力分析表明，BA在高达1000μM的测试浓度下没有细胞毒性。亚毒性浓度用于检测氧化应激状态。BA暴露以浓度依赖的方式显着降低了1000μM时的GSH水平和CAT活性。但是，SOD活性在测试浓度（100-1000μM）下增加。此外，在500和1000μM的BA下，ΔΨm显着降低，而caspase-3活性没有明显改变。结论这些发现表明，BA在较高浓度下不具有细胞毒性和凋亡作用，但可能会在TM3 Leydig细胞中轻微诱导氧化应激。结果细胞活力分析表明，BA在高达1000μM的测试浓度下没有细胞毒性。亚毒性浓度用于检测氧化应激状态。BA暴露以浓度依赖的方式显着降低了1000μM时的GSH水平和CAT活性。但是，SOD活性在测试浓度（100-1000μM）下增加。此外，在500和1000μM的BA下，ΔΨm显着降低，而caspase-3活性没有明显改变。结论这些发现表明，BA在较高浓度下不具有细胞毒性和凋亡作用，但可能会在TM3 Leydig细胞中轻微诱导氧化应激。BA暴露以浓度依赖的方式显着降低了1000μM时的GSH水平和CAT活性。但是，SOD活性在测试浓度（100-1000μM）下增加。此外，在500和1000μM的BA下，ΔΨm显着降低，而caspase-3活性没有明显改变。结论这些发现表明，BA在较高浓度下不具有细胞毒性和凋亡作用，但可能会在TM3 Leydig细胞中轻微诱导氧化应激。BA暴露以浓度依赖的方式显着降低了1000μM时的GSH水平和CAT活性。但是，SOD活性在测试浓度（100-1000μM）下增加。此外，在500和1000μM的BA下，ΔΨm显着降低，而caspase-3活性没有明显改变。结论这些发现表明BA在较高的浓度下对TM3 Leydig细胞没有细胞毒性和凋亡作用，但可能会轻微诱导其氧化应激。