Kumar Ashok, Rao A R, Kimura H
Radiation and Cancer Biology Laboratory, University of Rajasthan, Jaipur, India.
Phytother Res. 2002 Feb;16(1):74-7. doi: 10.1002/ptr.873.
Radiosensitization by neem oil was studied using Balbc/3T3 cells and SCID cells. Neem oil enhanced the radiosensitivity of the cells when applied both during and after x-irradiation under aerobic conditions. Neem oil completely inhibited the repair of sublethal damage and potentially lethal damage repair in Balbc/3T3 cells. The cytofluorimeter data show that neem oil treatment before and after x-irradiation reduced the G(2) + M phase, thus inhibiting the expression of the radiation induced arrest of cells in the G(2) phase of the cell cycle. However, SCIK cells (derived from the SCID mouse), deficient in DSB repair, treated with neem oil did not show any enhancement in the radiosensitivity. There was no effect of neem oil on SLD repair or its inhibition in SCIK cells. These results suggest that neem oil enhanced the radiosensitivity of cells by interacting with residual damage after x-irradiation, thereby converting the sublethal damage or potentially lethal damage into lethal damage, inhibiting the double-strand break repair or reducing the G(2) phase of the cell cycle.
利用Balbc/3T3细胞和SCID细胞研究了印楝油的放射增敏作用。在有氧条件下，于X射线照射期间及照射后应用印楝油，可增强细胞的放射敏感性。印楝油完全抑制了Balbc/3T3细胞亚致死损伤的修复以及潜在致死损伤的修复。细胞荧光计数据显示，X射线照射前后用印楝油处理可减少G(2)+M期，从而抑制细胞周期G(2)期辐射诱导的细胞停滞表达。然而，缺乏双链断裂修复能力的源自SCID小鼠的SCIK细胞经印楝油处理后，放射敏感性未显示出任何增强。印楝油对SCIK细胞的亚致死损伤修复或其抑制没有影响。这些结果表明，印楝油通过与X射线照射后的残余损伤相互作用来增强细胞的放射敏感性，从而将亚致死损伤或潜在致死损伤转化为致死损伤，抑制双链断裂修复或缩短细胞周期的G(2)期。
