Marouani Neila, Tebourbi Olfa, Hallègue Dorsaf, Mokni Moncef, Yacoubi Mohamed Tahar, Sakly Mohsen, Benkhalifa Moncef, Rhouma Khémais Ben
1 Laboratory of Integrated Physiology, Faculty of Sciences, Bizerte, Jarzouna, Tunisia.
2 Department of Anatomy and Pathological Cytology, Farhat Hached University Hospital, Sousse, Tunisia.
Toxicol Ind Health. 2017 Feb;33(2):97-106. doi: 10.1177/0748233715600333. Epub 2016 Jul 10.
Hexavalent chromium (CrVI)-containing compounds, present in industrial settings and in the environment, are known as carcinogens and mutagens. The present study is designed to test the hypothesis that oxidative stress mediates CrVI-induced apoptosis in testis. Male Wistar rats received an intraperitoneal injection of potassium dichromate at doses of 1 and 2 mg kg. Superoxide anion production was assessed by the determination of the reduction of cytochrome c and iodonitrotetrazolium, lipid peroxidation (LPO), metallothioneins (MTs), and catalase (CAT) activity. Apoptosis was evaluated by DNA fragmentation detected by agarose gel electrophoresis. Germinal cells apoptosis was detected by toluidine blue staining. The expression of Bax and Bcl-2 proteins (Pts) was also investigated. After 15 days of treatment, an increase of LPO and MT levels occurred, while CAT activity was decreased. Testicular tissues of treated rats showed pronounced degradation of the DNA into oligonucleotides as seen in the typical electrophoretic DNA ladder pattern. Intense apoptosis was observed in germinal cells of Cr-exposed rats. Bax Pt expression was induced in spermatogonia and spermatocytes cells of CrVI-treated rats. In contrast, Bcl-2 Pt was occasionally observed in germ cells of CrVI-exposed rats. These results clearly suggest that CrVI subacute treatment causes oxidative stress in rat testis leading to apoptosis.
存在于工业环境和自然环境中的含六价铬（CrVI）化合物被认为是致癌物和诱变剂。本研究旨在验证氧化应激介导CrVI诱导睾丸细胞凋亡这一假说。雄性Wistar大鼠腹腔注射剂量为1和2 mg/kg的重铬酸钾。通过测定细胞色素c和碘硝基四氮唑的还原率、脂质过氧化（LPO）、金属硫蛋白（MTs）以及过氧化氢酶（CAT）活性来评估超氧阴离子的产生。通过琼脂糖凝胶电泳检测DNA片段化来评估细胞凋亡。通过甲苯胺蓝染色检测生殖细胞凋亡。同时也研究了Bax和Bcl-2蛋白（Pts）的表达。治疗15天后，LPO和MT水平升高，而CAT活性降低。处理组大鼠的睾丸组织显示出DNA明显降解为寡核苷酸，这在典型的电泳DNA梯状图谱中可见。在Cr暴露大鼠的生殖细胞中观察到强烈的细胞凋亡。在CrVI处理大鼠的精原细胞和精母细胞中诱导了Bax Pt表达。相反，在CrVI暴露大鼠的生殖细胞中偶尔观察到Bcl-2 Pt。这些结果清楚地表明，CrVI亚急性处理会导致大鼠睾丸氧化应激，进而导致细胞凋亡。
