Schaaf G J, Maas R F M, de Groene E M, Fink-Gremmels J
Department of Veterinary Pharmacology, Pharmacy and Toxicology, Faculty of Veterinary Medicine, Utrecht University, The Netherlands
Free Radic Res. 2002 Aug;36(8):835-43. doi: 10.1080/1071576021000005267.
Induction of heme oxygenase-1 (HO-1) may serve as an immediate protective response during treatment with the cytostatic drug cisplatin (CDDP). Oxidative pathways participate in the characteristic nephrotoxicity of CDDP. In the present study, cultured tubular cells (LLC-PK1) were used to investigate whether induction of HO provided protection against CDDP by maintaining the cellular redox balance. The antioxidants, alpha-tocopherol (TOCO) and N-acetylcysteine (NAC), were used to demonstrate that elevation of ROS levels contribute to the development of CDDP-induced cytotoxicity. Chemical modulators of HO activity were used to investigate the role of HO herein. Hemin was used to specifically induce HO-1, while exposure of the cells to tin-protoporphyrin (SnPP) was shown to inhibit HO activity. Hemin treatment prior to CDDP-exposure significantly decreased the generation of ROS to control levels, while inhibition of HO increased the ROS levels beyond the levels measured in cells treated with CDDP alone. Furthermore, HO induction protected significantly against the cytotoxicity of CDDP, although this protection was limited. Similar results were obtained when the cells were preincubated with TOCO, suggesting that mechanisms other than impairment of the redox ratio are important in CDDP-induced loss of cell viability in vitro. In addition, SnPP treatment exacerbated the oxidative response and cytotoxicity of CDDP, especially at low CDDP concentrations. We therefore conclude that HO is able to directly limit the CDDP-induced oxidative stress response and thus serves as safeguard of the cellular redox balance.
诱导血红素加氧酶-1（HO-1）可能是在使用细胞毒性药物顺铂（CDDP）治疗期间的一种即时保护反应。氧化途径参与了CDDP的特征性肾毒性。在本研究中，使用培养的肾小管细胞（LLC-PK1）来研究HO的诱导是否通过维持细胞氧化还原平衡来提供对CDDP的保护。抗氧化剂α-生育酚（TOCO）和N-乙酰半胱氨酸（NAC）被用于证明活性氧（ROS）水平的升高有助于CDDP诱导的细胞毒性的发展。使用HO活性的化学调节剂来研究HO在其中的作用。血红素被用于特异性诱导HO-1，而将细胞暴露于锡原卟啉（SnPP）被证明可抑制HO活性。在CDDP暴露之前进行血红素处理可显著将ROS的产生降低至对照水平，而抑制HO则使ROS水平升高至超过仅用CDDP处理的细胞中测得的水平。此外，HO的诱导对CDDP的细胞毒性有显著的保护作用，尽管这种保护是有限的。当细胞与TOCO预孵育时也获得了类似的结果，这表明除了氧化还原比率受损之外的机制在体外CDDP诱导的细胞活力丧失中也很重要。此外，SnPP处理加剧了CDDP的氧化反应和细胞毒性，尤其是在低CDDP浓度下。因此，我们得出结论，HO能够直接限制CDDP诱导的氧化应激反应，从而作为细胞氧化还原平衡的保障。
