Response to γ-irradiation in V79 cells conditioned by repeated treatment with low doses of hydrogen peroxide

Abstract

Chinese hamster V79 cells were conditioned by repeated treatment with low doses of hydrogen peroxide. After this treatment, the conditioned cells were compared to parental V79 cells with regard to different endpoints. It was found that, compared to parental cells, the conditioned cells tolerated low serum concentrations better, they suffered from higher levels of aneuploidy, and they showed enhanced antioxidant defense. When exposed to gamma-rays, they suffered from lipid peroxidation to a lesser extent, were more resistant to cell killing, exhibited higher mutation frequency at the HGPRT locus, and showed lower frequency of apoptosis. These cells also induced antioxidant enzymes in response to gamma-ray exposure that differently was from than the parental cells. Overall, the data suggest a stable adaptive response in the conditioned cells.

Current Importance and Potential Use of Low Doses of Gamma Radiation in Forest Species

“…Thus, radioadaptive response induction expresses the ability of low dose radiation to induce cellular changes that alter the level of subsequent radiation-induced or spontaneous damage (Amundson et al, 1999). The exposure to minimal stress inducing a very low level of damage can trigger an AR resulting in increased resistance to higher levels of the same or of other types of stress (Patra et al, 2003;Asad et al, 2004;Girigoswami & Ghosh, 2005;Yan et al, 2006). The AR could be considered a nonspecific phenomenon and have been confirmed but not explained by many studies.…”

Adaptive response: some underlying mechanisms and open questions

“…Coleman et al, 2005;Girigoswami and Ghosh, 2005;Lanza et al, 2005). et al (2003) showed that the cell responses to ionizing radiation in lymphocytes of radiation workers involved altered expression of genes associated with cell cycle regulation, DNA repair, signal transduction, apoptosis induction/tumorigenesis and damage response/ maintenance of genetic stability (P53-related functions).…”

“…In spite of the variation in AR in different systems, it has been postulated that AR analysis could be used for assaying DNA repair capacity . It has also been suggested that membrane damage may switch on some of these responses (Skov et al, 1994) and/or be reduced as a result of AR (Girigoswami and Ghosh, 2005;El-Tayeb et al, 2006). 398 Adaptive response: Mechanisms and questions Does the AR operate via up-regulation of DNA repair?…”

“…Thus, radioadaptive response induction expresses the ability of low dose radiation to induce cellular changes that alter the level of subsequent radiation-induced or spontaneous damage. The AR could be considered a nonspecific phenomenon -the exposure to minimal stress inducing a very low level of damage can trigger an AR resulting in increased resistance to higher levels of the same or of other types of stress (Joiner et al, 1996;Wolff, 1998;Joiner et al, 1999;Patra et al, 2003;Asad et al, 2004;Girigoswami and Ghosh, 2005;Yan et al, 2006). The AR has been observed in many different organisms: bacteria, yeast, the algae Oedogonium cardiacam, Chlamydomonas reinhardtii, Closterium monoliferum and Chlorella pyrenoidosa, in higher plants, insect cells, mammalian cells, human cells in vitro, and in animal models in vivo during a protracted (low dose-rate) exposure prior to an acute dose treatment Laszlo, 1971, 1973;Bryant, 1974Bryant, , 1975Bryant, , 1976Bryant, , 1979Cowie, 1976, 1978;Olivieri et al, 1984;Santier et al, 1985;Wolff et al, 1988;Boreham and Mitchel, 1991;Rieger et al, 1993;Mahmood et al, 1996;Salone et al, 1996;Panda et al, 1997;Asad et al, 1997Asad et al, , 1998Wolff, 1998;Nikolova et al,showing gene expression changes, DNA single-and double-strand breaks, biochemical analyses of enzymatic and/or non-enzymatic antioxidant defence system (Hillova and Drasil 1967;Bryant, 1975Bryant, , 1976Bryant, , 1979Rieger et al, 1993;Ikushima et al, 1996;Rigaud and Moustacchi, 1996;Panda et al, 1997;…”

Window Theory in Non-Ionizing Radiation-Induced Adaptive Responses

“…As discussed by RE Mitchel, "the adaptive response in mammalian cells and mammals operates within a certain window that can be defined by upper and lower dose thresholds, typically between about 1 and 100 mGy for a single low dose rate exposure" (Mitchel 2010). On the other hand, as indicated by investigators who worked on oxidative stress or ionizing radiation-induced adaptive responses (Bose Girigoswami and Ghosh 2005;Dimova et al 2008;Yan et al 2006), Jin's findings on RF pre-exposures support this theory that the induction of adaptive response requires a minimum level of damage to trigger this phenomenon. In this light, it seems that there are similar patterns for induction of adaptive response by ionizing and non-ionizing radiations.…”