鼻咽癌放疗前、中、后SOD和MT的动态变化及其意义初探

背景与目的:超氧阴离子自由基()和羟自由基(OH·)在肿瘤放射治疗过程中起着重要作用,超氧化物歧化酶(superoxidedismutase,SOD)和金属硫蛋白(metallothionein,MT)是和OH·的主要清除酶。目前有关鼻咽癌(nasophary-ngealcarcinoma,NPC)与SOD和MT关系的研究报道极少。本研究旨在了解NPC放疗过程中患者血清SOD活性和肿瘤组织MT表达的动态变化及意义。方法:从2000年12月至2002年1月,分别采用黄嘌呤氧化酶法和免疫组化法检测46例NPC患者放疗前、中、后外周静脉血T-SOD活性及肿瘤组织MT表达的动态变化。取26例确诊未患癌症者作为正常检测对照。结果:32例患者完成了3次T-SOD动态检测,放疗前T-SOD活性为(83.9±19.6)UN/ml,明显低于正常对照的(96.8±23.6)UN/ml(P<0.05)。放疗前、中、后血清T-SOD活性变化:早期(Ⅰ期)患者分别为(77.6±19.1)UN/ml、(87.1±18.6)UN/ml和(96.3±31.6)UN/ml(P>0.05);晚期(Ⅳ期)为(80.1±15.0)UN/ml、(78.0±35.4)UN/ml和(110.6±72.0)UN/ml(P>0.05);放疗近期疗效达CR患者为(79.8±18.2)UN/ml、(87.2±31.7)UN/ml和(94.8±36.3)UN/ml(P>0.05);PR为(98.5±18.6)UN/ml、(62.9±35.3)UN/ml和(79.2±27.3)UN/ml(P>0.05)。其中,27例NPC患者完成了3次MT检测,放疗前NPC组织MT表达率为(39.8±

Changes of superoxide dismutase (SOD) and metallothionien (MT) before,during, and after radiotherapy for nasopharyngeal carcinoma and their significance

BACKGROUND & OBJECTIVE: The superoxide anion and the hydroxyl radical (OH.) play an important role in the radiotherapy of tumors. The superoxide dismutase (SOD) and the metallothionien (MT) are the main enzymes to clear the superoxide anion and OH. Up to now, there are few reports on the relationship between the nasopharyngeal carcinoma (NPC) and SOD or MT. This study was conducted to observe the dynamic changes of the activity of total superoxide dismutase (T-SOD) in the serum and the expression of MT in the tissue from the NPC patients treated with radiotherapy. METHODS: From December 2000 to January 2002, 46 patients with NPC were selected randomly to test the activity of T-SOD in serum using xanthine oxidase method and the expression of MT in tissue using immunohistochemistry before, during, and after radiotherapy. And 26 persons without cancer were enrolled as normal control. RESULTS: Thirty-two patients were performed 3 times of examinations of T-SOD activity. The activity of T-SOD before radiotherapy (83.9+/-19.6 U(N)/ml) was lower than normal control (96.8+/-23.6 U(N)/ml) (P< 0.05). The activities of T-SOD in the serum samples before, during, and after the radiotherapy were 77.6+/-19.1, 87.1+/-18.6, and 96.3+/-31.6 in the NPC patients at stage I(P >0.05); 80.1+/-15.0, 78.0+/-35.4, and 110.6+/-72.0 in the NPC patients at stage IV(P >0.05); 79.8+/-18.2, 87.2+/-31.7, and 94.8+/-36.3 in the patients with complete response to radiotherapy (P >0.05); 98.5+/-18.6, 62.9+/-35.3, and 79.2+/-27.3 in the patients with part response to radiotherapy (P >0.05). Among the 32 patients, 27 patients were performed 3 times of tests of MT expression. The expression rate of MT in NPC tissues was 39.8+/-37.8% before radiotherapy, and markedly higher than the normal control 12.1+/-22.4% (P< 0.05). The expression rates of MT before, during, and after radiotherapy were 33.0+/-42.2%, 21.3+/-36.1%, and 5.0+/-10.0% in the tissues from the patients at stage I(P< 0.05); 62.2+/-40.5%, 9.2+/-12.8%, and 9.2+/-15.0% in the patients at stage IV( P< 0.05); 42.5+/-38.6%, 19.8+/-27.5%, and 10.0+/-13.9% in the patients with complete response to radiotherapy (P< 0.05); 32.3+/-37.2%, 1.43+/-2.43%, and 5.4+/-9.1% in the patients with part response to radiotherapy (P< 0.05). CONCLUSION: The test of T-SOD in serum may be helpful for the diagnosis of initial NPC. But the dynamic change of the activity of total T-SOD in radiotherapy was not obvious. The expression rates of MT in NPC tissues increased markedly before radiotherapy, and decreased obviously after radiotherapy.