Badr F M, El-Habit O H, Hamdy M, Hassan G A
Department of Anatomy, Faculty of Medicine, Suez Canal University, Ismailia, Egypt.
Mutat Res. 1998 May 11;414(1-3):157-63. doi: 10.1016/s1383-5718(98)00038-2.
The present study was carried out to evaluate the role of vitamin A (VA) on the induction of chromosomal aberrations (CA) in lymphocyte culture system and to investigate its modulating effect on chromosomal damage induced by gamma irradiation. Lymphocyte cultures from five healthy normal adult males were either treated with VA at a dose level of 2.0, 8.0 or 24.0 microg/ml or exposed to gamma-irradiation of 3.0 Gy, then followed immediately by a treatment with one of the above mentioned doses of VA. Non-treated cultures and cultures exposed to gamma-irradiation served as control for the two sets of experiments. Cultures were set up in duplicates and incubated for 48 h for assessment of CA. Treatment with VA alone increased CA demonstrating a dose-response effect. Addition of VA to gamma-irradiated cultures resulted in an inverse protective effect as the low dose of 2 microg/ml reduced the CA induced by radiation to about 1/3 rd whereas a dose of 8 microg/ml had a protective effect of 40% of the total damage and the large dose of 24 microg/ml had no or little effect. These results suggest that a proportion of the added VA may interfere with the radiation induced free radicals and other reactive metabolites which elevate CA. On the other hand, excessive amounts of VA increased toxicity and reduced effect on repair enzymes.
本研究旨在评估维生素A（VA）在淋巴细胞培养系统中对染色体畸变（CA）诱导作用的影响，并研究其对γ射线诱导的染色体损伤的调节作用。从五名健康正常成年男性采集淋巴细胞培养物，分别用剂量为2.0、8.0或24.0微克/毫升的VA处理，或暴露于3.0 Gy的γ射线照射下，然后立即用上述剂量之一的VA进行处理。未处理的培养物和暴露于γ射线照射的培养物作为两组实验的对照。培养物一式两份设置，并孵育48小时以评估染色体畸变。单独用VA处理会增加染色体畸变，呈现剂量反应效应。向γ射线照射的培养物中添加VA会产生反向保护作用，因为2微克/毫升的低剂量将辐射诱导的染色体畸变降低到约三分之一，而8微克/毫升的剂量对总损伤有40%的保护作用，24微克/毫升的大剂量则没有或几乎没有作用。这些结果表明，添加的VA的一部分可能会干扰辐射诱导的自由基和其他会增加染色体畸变的活性代谢物。另一方面，过量的VA会增加毒性并降低对修复酶的作用。
