Department of Regenerative Medicine, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan.
Environ Health Prev Med. 2013 Sep;18(5):377-85. doi: 10.1007/s12199-013-0336-8. Epub 2013 Apr 23.
Nitric oxide (NO) and inducible nitric oxide synthase enzyme (iNOS) have been implicated in various tumors. Hepatocellular carcinoma is a highly aggressive form of solid tumor. The lack of effective therapy necessitates the introduction of novel therapeutic strategies to counter this disease. Nigella sativa (NS) has been shown to have specific health benefits. The aim of this study was to investigate the in vivo modulation of the iNOS pathway by NS ethanolic extract (NSEE) and the implications of this effect as an antitumor therapeutic approach against diethylnitrosamine (DENA)-induced hepatocarcinogenesis.
Rats were divided into four groups, normal control, NSEE control, cancer control, and NSEE-DENA groups. The diagnosis of cancer was based on alpha-fetoprotein (AFP) levels and histological variations. Serum NO, tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) levels and serum iNOS activity were measured. Liver iNOS expression was investigated by reverse transcriptase (RT)-PCR and western blot assays.
Serum AFP, NO, TNF-α, and IL-6 levels and iNOS enzyme activity were significantly increased in rats treated with DENA. Significant up-regulation of liver iNOS mRNA and protein expression was also observed. Subsequent treatment with NSEE significantly reversed these effects and improved the histopathological changes in malignant liver tissue which appeared after treatment with DENA, without any toxic effect when given alone.
These results provide evidence that attenuation of the iNOS pathway and suppression of the inflammatory response mediated by TNF-α, and IL-6 could be implicated in the antitumor effect of NSEE. As such, our findings hold great promise for the utilization of NS as an effective natural therapeutic agent in the treatment of hepatocarcinogenesis.
一氧化氮（NO）和诱导型一氧化氮合酶（iNOS）已被认为与各种肿瘤有关。肝细胞癌是一种高度侵袭性的实体瘤。由于缺乏有效的治疗方法，因此需要引入新的治疗策略来对抗这种疾病。黑种草（NS）已被证明具有特定的健康益处。本研究旨在研究 NS 乙醇提取物（NSEE）对 iNOS 途径的体内调节作用，以及这种作用作为一种针对二乙基亚硝胺（DENA）诱导的肝癌发生的抗肿瘤治疗方法的意义。
将大鼠分为正常对照组、NSEE 对照组、癌症对照组和 NSEE-DENA 组。根据甲胎蛋白（AFP）水平和组织学变化诊断癌症。测量血清 NO、肿瘤坏死因子-α（TNF-α）和白细胞介素-6（IL-6）水平和血清 iNOS 活性。通过逆转录聚合酶链反应（RT-PCR）和 Western blot 检测肝 iNOS 表达。
用 DENA 处理的大鼠血清 AFP、NO、TNF-α和 IL-6 水平和 iNOS 酶活性显着升高。还观察到肝 iNOS mRNA 和蛋白表达的显着上调。随后用 NSEE 治疗可显着逆转这些作用，并改善 DENA 处理后恶性肝组织的组织病理学变化，而单独使用时无任何毒性作用。
这些结果提供了证据，表明 iNOS 途径的衰减和 TNF-α和 IL-6 介导的炎症反应的抑制可能与 NSEE 的抗肿瘤作用有关。因此，我们的研究结果为将 NS 作为治疗肝癌的有效天然治疗剂提供了很大的希望。
