【关键词】 肿瘤;硫化氢;抗肿瘤联合化疗方案;感染
the pathophysiological role of hydrogen sulfide during the process of neutropenia complicated with infection in patients with malignant tumors after chemotherapy zhao weijian, pang tao，yin xiaoli,et al.department of oncology, anguo hospital,hebei,anguo 071200,china
【abstract】 objective to investigate the pathophysiological role of hydrogen sulfide (h2s) during the process of neutropenia complicated with infection in patients with malignant tumors after chemotherapy.methods 52 patients with malignant tumor (the experimental group) and 32 nontumor patients (the control group) were enrolled in the study. the patients in experimental group were pathologically diagnosed as malignant tumors, including stomach tumor, lung cancer, liver cancer, esophageal carcinoma and leukemia. after chemotherapy, the patients had neutropenia.the contents of hydrogen sulfide were detected by sensitive sulphur electrode method, and tumor necrosis factor alpha (tnfα) and interleukin1 (il1) levels were determined by enzymelinked immunosorbent assay (elisa).results after the patients in control group were infected, the serum levels of h2s, tnfα and il1 were significantly increased, as compared with those without infection (p<0.05).however, after the infection was controlled, the levels of h2s, tnfα and il1 were obviously decreased (p<0.05). the serum levels of h2s, tnfα and il1 in experimental group were much higher than those in control group(p<0.01). after chemotherapy, the peripheral white blood cells (wbc) were reduced to (1.0～2.0)×109/l. before infection, the serum h2s levels had no obvious change (p>0.05), while the serum levels of tnfα and il1 were significantly decreased, as compared with those before chemotherapy. when patients were infected concurrently, serum h2s levels were further increased (p<0.01), and serum il1 levels were increased slightly, but the difference was not significant (p>0.05). however, the serum tnfα levels were significantly decreased (p<0.05).conclusion the h2s plays an important pathophysiological role during the process of neutropenia complicated with infection in patients with malignant tumors after chemotherapy.
【key words】 malignant tumor; hydrogen sulfide;antineoplastic combined chemotherapy protocols;infection
恶性肿瘤是危害人类健康的一大杀手，随着手术及化疗水平的提高，其5年无病生存率已得到很大改善。但化疗可致粒细胞减少极易并发感染，及时给予抗感染治疗既能降低患者感染的程度及风险，又能为患者节约治疗费用。硫化氢(hydrogen sulfide,h2s)是继no、co之后的第三个气体信号分子，它可以在哺乳动物的多种组织细胞中内源性产生，在心血管、中枢神经系统、胃肠道发挥重要的病理生理学作用[1-5]。h2s在炎症过程中的生物学作用已引起广大学者的关注。而肿瘤患者感染后h2s含量的变化笔者尚未见相关报道。因此，进一步探讨h2s参与肿瘤患者化疗后粒细胞减少合并感染的病理生理学作用具有重要的临床指导作用。
1 资料与方法
1.1 一般资料 2005年8月至2009年8月我院肿瘤科住院患者共52例(试验组)，化疗后外周血白细胞(1.0～2.0)×109/l，伴或不伴感染。其中男30例，女22例;年龄25～73岁，中位年龄55.5岁;均经病理检查确诊为恶性肿瘤，包括胃癌、肺癌、肝癌、食管癌及白血病。所有患者病程均不足1年，入院时一般状况良好。选取我院内科及外科非肿瘤患者32例为对照组，其中男18例，女14例;年龄25～67岁，中位年龄53岁;感染前后常规检查时取血。
1.2 标本采集 患者均于感染时常规取血，所有标本立即3 000 r/min低温离心，分装后-80℃冰箱保存。
1.3 血清h2s水平测定 采用敏感硫电极法测定[6]。电极在每次使用前须在去离子水中活化2 h以上。打开离子计，将测定项调至mv档，斜率调至100%。将血浆0.5 ml与等体积的抗氧化液混合。将敏感硫电极与参比电极一起浸入到样品中，待读数稳定后记录，用去离子水冲洗电极，每测一个样品结束，电极必须浸入去离子水中以保持其活化状态。根据s2-溶液的标准曲线计算出h2s的含量。
1.4 血清肿瘤坏死因子α(tnfα)和白介素1(il1)水平测定 采用酶联免疫吸附测定(elisa)法，试剂盒购于深圳市科润达生物工程有限公司，操作严格按照试剂盒说明书进行，用酶标仪(lecan safire autira)在490 nm处读取od值。以上两试剂盒操作步骤严格无菌操作。
1.5 统计学分析 应用spss 10.0统计软件，计量资料以±s表示，2组间的比较采用成组设计的t检验，多组比较采用单因素方差分析及两两比较的q检验，两变量间的相关性采用线性相关分析，p<0.05为差异有统计学意义。
2 结果
2.1 对照组感染前后血清h2s、tnfα和il1水平变化 对照组在合并感染时血清h2s、tnfα和il1水平均较未感染时明显升高(p<0.05)。而感染控制后三者水平较感染时显著下降(p<0.05)。见表1。
表1 对照组血清h2s、tnfα和il1水平变化n=32，±s
检测指标感染前感染时感染控制后
h2s(μmol/l)39±6#45±440±6#
tnfα(ng/l)0.22±0.07#1.86±0.840.64±0.47#
il1(ng/l)7.1±2.6*16.5±3.88.7±2.9*
注：与感染时比较，*p<0.05，#p<0.01
2.2 试验组感染前后血清h2s、tnfα和il1水平变化 试验组血清h2s、tnfα和il1水平均较对照组显著升高(p<0.01)。化疗后患者白细胞总数降低[(1.0～2.0)×109/l]，未感染时血清h2s水平即较化疗前变化不明显(p>0.05)。而tnfα和il1水平较化疗前明显下降(p<0.01)。合并感染时血清h2s水平较未感染时显著升高(p<0.01);而血清tnf水平较未感染时明显下降(p<0.01);血清il1水平较未感染时略有升高，但差异无统计学意义(p>0.05)。见表2。
表2 试验组血清h2s、tnfα和il1水平变化n=52，±s
检测指标化疗前化疗后未感染时化疗后感染时
h2s(μmol/l)68±871±983±10*
tnfα(ng/l)42±6*33±629±6*
il1(ng/l)31±5*28±530±7
注：与化疗后未感染时比较，*p<0.01
2.3 血清h2s水平与tnfα和il2水平的相关性分析 试验组与对照组血清h2s水平与tnfα和il1水平无相关性(相关系数分别为0.732、0.698，p>0.05)。
3 讨论
tnf是一类能直接造成肿瘤细胞死亡的细胞因子，低浓度时生物学活性主要表现为抗感染、引起炎性反应和抗肿瘤，而大量的tnf则引起恶病质，有促进肿瘤生长的作用。tnf还能刺激巨噬细胞分泌il1、il6、趋化因子等，在机体炎性反应中起重要作用[7]。tnfα和il1作为炎性细胞因子，可以反映机体的炎性改变[8]。本研究结果发现，对照组血清h2s、tnfα和il1水平在感染后显著升高，而感染控制后又显著下降，三者变化趋势相一致，因此在反映炎症改变的程度上h2s与tnfα和il1具有类似的意义。
最近有关h2s参与炎性反应的研究多见动物实验报道[1-5]。在各种炎性性疾病(如胰腺炎、败血症和内毒素血症等)的动物模型中，h2s过量产生，参与调节炎性反应的程度及与器官损伤有关;抑制h2s的生成可以保护实验动物对抗炎性性疾病[2]。另外，低剂量的硫氢化钠(nahs，h2s供体)在炎症局部(如非甾体抗炎药所致胃溃疡)可发挥抗炎效应[3-9]。
试验组血清h2s、tnfα和il1水平在化疗前即显著高于对照组，提示三者均参与了恶性肿瘤的发病过程，这与文献报道h2s抑制人类单个核细胞的凋亡相一致[10,11]。h2s参与炎性反应的机制尚不明确，其对炎性的调控作用可能是通过调节炎症过程中白细胞的功能、白细胞的运输及免疫细胞的存活来实现的[4]。也有文献报道h2s还可诱导神经肽(如p物质、降钙素基因相关肽)的产生和释放，而这些神经肽是促炎性反应因子，进一步促进炎性反应[5]。恶性肿瘤患者化疗后粒细胞减少[白细胞(1.0～2.0)×109]，合并感染时白细胞的抗感染能力降低，白细胞的功能也相应降低，可能会刺激机体产生并分泌大量的h2s，从而负反馈调节白细胞的抗感染能力;也可能调动机体其他免疫细胞，如单核巨噬细胞，参与机体的炎性反应。
本试验的结果也表明血清h2s水平可以反映机体的感染状况，在一定程度上，感染程度越重，血清h2s水平越高，其确切机制尚需进一步深入研究。总之，气体信号分子h2s参与了恶性肿瘤患者化疗后合并感染时的发病过程，并发挥着重要的的病理生理作用。
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作者：赵维健 庞涛 尹晓丽 何惠清 作者单位：071200 河北省安国市医院肿瘤科
