Effects of low and high LET radiations on bystander human lung fibroblast cell survival

Rajamanickam Baskar, Adayabalam S Balajee, Charles R Geard
International Journal of Radiation Biology 2007, 83 (8): 551-9

PURPOSE: This investigation is aimed to determine the role of low LET (linear energy transfer, gamma-rays) and high LET (alpha-particles) radiations on bystander effect of using the same type of cells and its implications on colony-forming efficiency from a single cell.

MATERIALS AND METHODS: Normal human fetal lung (MRC-5), immortalized repair deficient ataxia telangiectasia mutated (ATM) (GM5,849C) and normal (GM637H) fibroblast cells were used. Colony-forming efficiency in bystander cells (GM637H) was studied using the medium transfer technique from the two donor (MRC-5 and GM5,849C) cells and the procedure followed for bystander treatment is presented schematically in Figure 1. Evidence of change in colony formation in bystander cells, was assessed by scavenging nitric oxide (NO).

RESULTS: Enhancement of 10 - 30% in colony-forming efficiency was observed in bystander GM637H cells treated with irradiated conditioned medium (ICM) from MRC-5 cells collected 1 h after different doses of either gamma-rays (1, 2.5, 5 and 10 Gy) or alpha particles (0.25, 0.5, 1 and 2.5 Gy) irradiation. Similar results were obtained when ICM derived from the ATM (GM5,849C) cells. However, the stimulation was not dose dependent. Furthermore, we also show that the increase in dilutions of ICM (1:1, 1:5 and 1:10) showed an inverse correlation with cloning efficiency. Treatment of MRC-5 cells with PTIO (2-phenyl-4, 4, 5, 5-tetramethylimidazoline-1-oxyl-3-oxide) a NO scavenger, 1 h prior to irradiation reduced the enhancement of ICM mediated cell survival.

CONCLUSIONS: In the present study, though both the low and high LET radiations enhanced the clonogenic potential of the bystander recipient cells, medium from the ATM defective (GM5,849C) cells after gamma-irradiation showed less stimulating effect than the medium from the normal (MRC-5) cells. However, after alpha-irradiation an inverse effect was seen. NO may play an important role in enhancing the growth potential in these bystander cells.

Full Text Links

Find Full Text Links for this Article


You are not logged in. Sign Up or Log In to join the discussion.

Related Papers

Remove bar
Read by QxMD icon Read

Save your favorite articles in one place with a free QxMD account.


Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"