Objective To investigate the effect of ex vivo hyperthermia(HT) and 137Cs-irradiation on mi-cronucleus(MN) production in cytokinesis-blocked lymphocytes. Methods The peripheral blood samples from thesame cancer patients(n= 6) before and during fractionated partial-body radiotherapy(xRT) were collected, andthen, the whole blood cultures were heated at 43.5℃ for 60min, followed by 137Cs-irradiation(0-4 Gy). The con-trol cultures from the same patients were incubated at 37℃ after being exposed to radiation. The lymphocyteswere then stimulated with PHA. Cytochalasin B was applied at 44h, and lymphocytes were harvested at 72h. MNfrequency was determined on Giemsa stained slides. Results Before xRT in patients, HT(43. 5℃ ) significantlyincreased the MN yield(mean + SEM) in unirradiated lymphocytes fron 15.6 + 2.8(37℃ ) to 39.7 + 10.9. Fur-ther, in patients either before or during xRT, when the lymphocytes were treated with HT(43. 5℃ ) and com-bined with ex vivo irradiation, the MN yield (Y) muld be estimated by a linear equation Y = C + αD. ConclusionsOur findings indicate that as measured by the MN production in cytokinesis-blocked lymphocytes, HT alone at43. 5℃ induced DNA damage. Moreover, it enhanced the radiation-induced cytogenetic damage. Therefore, theapplication of HT may impair the T-cell function in cancer patients who are receiving radiotherapy.%目的研究体外高温(HT)和137铯对胞质分裂阻滞的外周血淋巴细胞(PBL)微核(MN)产生的影响.方法收集6例分区放疗(xRT)前和放疗中的肿瘤患者外周血,全血培养在43.5℃下处理60min后,以137铯射线照射;对照为同患者的外周血.暴露于射线后在37℃孵育60min,以PHA刺激淋巴细胞,培养44h时应用细胞松驰素B,72h时收集淋巴细胞,吉姆萨染色测定MN率.结果高温(43.5℃)能使未照射淋巴细胞的MN率(M±SE)明显提高,从15.6±2.8(37℃)提高到39.7±10.9.患者xRT前或xRT中,当淋巴细胞用高温(43.5℃)处理联用体外照射时,MN率用线性方程Y=C+αD评价.结论胞质分裂阻滞的淋巴细胞MN率测量结果表明,单纯43.5℃高温可诱导DNA损伤,并提高射线诱导的细胞遗传学损伤,且应用HT可损害接受放疗肿瘤患者的T细胞功能.
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