Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Rua Cel Nunes de Melo, 1315 Rodolfo Teófilo, Fortaleza, Ceará 60430-270, Brazil.
Cancer Chemother Pharmacol. 2012 Apr;69(4):931-42. doi: 10.1007/s00280-011-1780-z. Epub 2011 Nov 20.
Intestinal mucositis and the closely associated diarrhea are common costly side effects of irinotecan. Cytokine modulators, such as thalidomide and pentoxifylline, are found capable of attenuating intestinal mucositis progression. Nitric oxide (NO) seems to be a key mediator of the antineoplastic drug toxicity. The aim of this study was to investigate the role of NO on the pathogenesis of intestinal mucositis, as well as the participation of cytokines upon inducible nitric oxide synthase (iNOS) expression in irinotecan-induced intestinal mucositis.
iNOS-knockout (iNOS(-/-)) and C57BL/6 (WT, wild type) animals (n = 5-6) were given either saline or irinotecan (60 mg/kg i.p for 4 days), with or without pretreatment with aminoguanidine (50 mg/kg s.c.), thalidomide (60 mg/kg s.c), infliximab (5 mg/kg i.v.), or pentoxifylline (1.7 mg/kg s.c). On day 5, diarrhea was assessed, and following euthanasia, proximal intestinal samples were obtained for myeloperoxidase (MPO) and iNOS activity, morphometric analysis, western blot and immunohistochemistry to iNOS, cytokine dosage, and for in vitro evaluation of gut contractility.
Irinotecan induced severe diarrhea and intestinal smooth muscle over-contractility, accompanied with histopathological changes. Additionally, increased MPO and iNOS activity and iNOS immunoexpression were found in WT animals treated with irinotecan. The rise in MPO, smooth muscle over-contractility, and diarrhea were abrogated in aminoguanidine-treated and iNOS(-/-) mice. Moreover, through western blot, we verified that infliximab and pentoxifylline significantly inhibited irinotecan-induced iNOS expression. In addition, cytokine concentration was found only partially decreased in irinotecan-treated iNOS(-/-) mice when compared with wild-type animals that were given irinotecan.
This study suggests a role of nitric oxide in the pathogenesis of irinotecan-induced intestinal mucositis and also provides evidence for the participation of cytokines on iNOS induction.
伊立替康引起的肠道黏膜炎及其密切相关的腹泻是常见的、代价高昂的副作用。细胞因子调节剂，如沙利度胺和己酮可可碱，被发现能够减轻肠道黏膜炎的进展。一氧化氮（NO）似乎是抗肿瘤药物毒性的关键介质。本研究旨在探讨 NO 在肠道黏膜炎发病机制中的作用，以及细胞因子在伊立替康诱导的肠道黏膜炎中诱导型一氧化氮合酶（iNOS）表达中的作用。
iNOS 敲除（iNOS(-/-)）和 C57BL/6（WT，野生型）动物（n=5-6）分别给予生理盐水或伊立替康（60mg/kg 腹腔注射，共 4 天），并在给予氨基胍（50mg/kg 皮下注射）、沙利度胺（60mg/kg 皮下注射）、英夫利昔单抗（5mg/kg 静脉注射）或己酮可可碱（1.7mg/kg 皮下注射）预处理或不预处理的情况下。第 5 天评估腹泻情况，安乐死后获取近端肠道样本进行髓过氧化物酶（MPO）和 iNOS 活性、形态学分析、western blot 和免疫组织化学检测 iNOS、细胞因子剂量，并进行肠道收缩性的体外评估。
伊立替康诱导严重腹泻和肠道平滑肌过度收缩，伴有组织病理学改变。此外，在给予伊立替康的 WT 动物中发现 MPO 和 iNOS 活性和 iNOS 免疫表达增加。氨基胍处理和 iNOS(-/-)小鼠中 MPO、平滑肌过度收缩和腹泻的增加被消除。此外，通过 western blot，我们证实英夫利昔单抗和己酮可可碱可显著抑制伊立替康诱导的 iNOS 表达。此外，与给予伊立替康的野生型动物相比，伊立替康处理的 iNOS(-/-)小鼠中的细胞因子浓度仅部分降低。
本研究表明一氧化氮在伊立替康诱导的肠道黏膜炎发病机制中起作用，并提供了细胞因子参与 iNOS 诱导的证据。
