Ramirez D C, Gimenez M S
Department of Biochemistry and Biological Sciences, Faculty of Chemistry, Biochemistry and Pharmacy, National University of San Luis, Avenida Ejercito de los Andes 950, 5700, San Luis, Argentina.
Toxicology. 2000 Apr 20;146(1):61-72. doi: 10.1016/s0300-483x(00)00166-9.
Different protocols of cadmium (Cd) exposure in non-cytotoxic conditions (i.e. 10 microM Cd for 18 h), and their effect on nitric oxide (NO) generation induced by NO inductor agents (NOIA) in peritoneal macrophages (pM) were studied. In all cases, NOIA (i.e. bacterial lipopolysaccharide [LPS], phorbol ester [PMA], okadaic acid [OA] or their combinations [LPS/OA] and [LPS/PMA]) were added at the beginning of the first incubation, only. Simultaneously exposure with 10 microM Cd enhanced NO generation and inducible NO synthase (iNOS) expression evoked by LPS, OA, PMA; those induced by LPS/PMA were not modified; and those caused by LPS/OA in relation to culture without Cd (medium) decreased. Double incubation, either with or without Cd (Cd+Cd or medium+medium), or Cd added at the start of the first or second incubation only (Cd+medium or medium+Cd), were tested. After the second incubation, medium+Cd protocol produced the highest NO generation in relation to other exposure protocols. When NO production was measured at the end of the second incubation, Cd+medium protocol enhanced NO production induced by OA, and LPS/OA, while medium+Cd protocol enhanced the response to LPS, PMA, and LPS/OA, in both cases in relation to the first incubation. Cd+Cd incubation protocol decreases the response to all NOIA in relation to another protocols. Cd effect on NO generation in macrophages is dependent on protocol and timing of exposure.
研究了在非细胞毒性条件下（即10微摩尔镉处理18小时）不同的镉（Cd）暴露方案，以及它们对腹膜巨噬细胞（pM）中由一氧化氮诱导剂（NOIA）诱导产生的一氧化氮（NO）的影响。在所有情况下，仅在第一次孵育开始时添加NOIA（即细菌脂多糖[LPS]、佛波酯[PMA]、冈田酸[OA]或它们的组合[LPS/OA]和[LPS/PMA]）。与10微摩尔镉同时暴露可增强LPS、OA、PMA诱导的NO生成和诱导型一氧化氮合酶（iNOS）表达；LPS/PMA诱导的情况未发生改变；与无镉培养（培养基）相比，LPS/OA诱导的情况有所下降。测试了双孵育，有镉或无镉（Cd+Cd或培养基+培养基），或仅在第一次或第二次孵育开始时添加镉（Cd+培养基或培养基+Cd）。在第二次孵育后，与其他暴露方案相比，培养基+镉方案产生的NO生成量最高。在第二次孵育结束时测量NO生成量时，Cd+培养基方案增强了OA和LPS/OA诱导的NO生成，而培养基+镉方案增强了对LPS、PMA和LPS/OA的反应，两种情况均相对于第一次孵育。与其他方案相比，Cd+Cd孵育方案降低了对所有NOIA的反应。镉对巨噬细胞中NO生成的影响取决于暴露方案和时间。
